Accession for Moving Coil
Printed From: Graham Slee Hifi System Components
Category: Turntable Audio
Forum Name: Graham Slee Phono Stages
Forum Description: Questions, answers, and product information zone for Graham Slee Phono Stage Preamps
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=3003
Printed Date: 24 Apr 2024 at 10:11am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com
Topic: Accession for Moving Coil
Posted By: Graham Slee
Subject: Accession for Moving Coil
Date Posted: 18 Aug 2016 at 2:15pm
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Listening right now to the Accession MC. Yes, as rumoured elsewhere on this forum my aim was to extend the Accession's technology to work directly with moving coil cartridges. The important function of the Accession phono stage is to EQ the rising response of magnetic cartridges. This isn't something subtle, it is a 45 degree upward slope where the output of the cartridge doubles every octave (every doubling in frequency). Not many know about this, but now you do. What I didn't want to do is place a pre-pre before the Accession single slope integrator because that kind of defeats the object. Direct conversion gives rise to much more information being passed through without the ups and downs to frequency and phase conventional phono stages do right at the frequencies we are most sensitive to. OK, those ups and downs have to take place to apply the right EQ for the record, but right in the middle of such extreme amplification as needed by a phono cartridge, isn't the place to do it - but we all did. For years I struggled with the awkward interaction of cartridge and record equalisation done in one, which conventional wisdom says should be so. They even split the curve, did it passively, or a combination of active and passive techniques, and in doing so it may improve things, but still we have a serious interaction to smooth over. I made a number of early Reflex phono stages all with slightly different resistor values to shift the so called 318uS (500Hz to you and me) zero up and down by tiny increments. If anything it caused a 0.1dB difference in tolerance, and in fact with one or two it made it 0.1dB more accurate. The difference it made to the sound was unbelievable - most of it in a negative sense. It just goes to show how sensitive the adjustment of the 318uS zero is. There is no real way to get it accurate. Audio researcher Stanley P Lipsh*tz proposed a number of equations, but in real life the results are far from ideal (how dare I say that?!...) It's because the RIAA is entwined in the amplification circuit or circuits in one way or another that discrepancies creep in. They are unavoidable. Amplifier stages of all kinds are not perfect - they don't fit with ideal theory. And then there's another effect I have found over the years and whenever an integrator's response starts to kick up before falling off again - exactly what an RIAA stage does, the sound suffers. All amplifiers have an integrator response somewhere when you think of it. Mainly it's beyond the audible frequencies where the response droops off toward its closure frequency. For stability the slope where it passes through unity gain has to be close to 20dB/decade, but below unity gain a circuit can kick up again, and even though it remains safely below unity gain, the effects can be heard. So when you arrange to have a zero in a 20dB/decade slope within the audible range it is going to exhibit itself in a non too pleasing way. The Accession does away with the zero in the gain stage and shifts it downstream to where it is less likely to offend. In fact, because of the cartridge EQ it becomes a pole similar to what you get in tone controls (and that's what they originally used for EQ!) But that doesn't explain what effect having a pre-pre (a preceding stage) causes, and why I think for the Accession it doesn't bring much to the table. Every stage has its own open-loop frequency response which isn't tremendously wide, so negative feedback which reduces gain spreads it out a bit to get that wide frequency response needed for audio. For the lower frequencies you therefore get true 180 degree negative feedback, which is good, and at higher frequencies you get around 90 degree negative feedback, which isn't as good because it favours the rising edges and in doing so moves the ear's focus toward the highs, and the lows can appear a little too tight - even though the analyser proves a flat response. With the Accession integrator nearly all the negative feedback (above 50Hz) is 90 degrees, and based on the above it sounds like I'm talking myself out of a job. The difference is the incoming signal is rising at 20dB/decade so is plus 90 degrees, and if you now add the integrator's -90 degrees response, it totals 180 degrees. This explains the low frequency improvement the Accession brings - the bass has some meat to it - it sounds real. Therefore, in my opinion, it would be best to do direct conversion from the cartridge and not have any preceding stage. This is where I needed a volunteer who has the necessary equipment for comparison between the Elevator with Accession, and the Accession MC prototype. Who? No other than our resident prolific you tube channel creator Bob! Now, a digital representation of vinyl won't sound as good as playing vinyl direct, but Bob has the requisite items and a wide selection of moving coil cartridges to play with. After uploading my choice of album tracks to some web space we were able to download the FLACs for a good old comparison session. After several email exchanges discussing all our findings: Bob's, mine, John's and Leo's, we all concluded that the Accession MC alone had the edge. There are limitations however. The range of input impedances is not as great as it is using the Elevator EXP as MC step-up. The Accession MC can only go to 500 ohms maximum. I've included three options of 100 ohms (pretty standard); 300 ohms which many ask me for; and the maximum 500 ohms which will add some sparkle to such as the DL103 - not quite the 1k tg prefers but close enough I would think. So there we have it - the Accession MC. And now Bob will hopefully chip in with his own words? I'm thinking about getting five made and out to the loaner program so members can beta it. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Replies:
Posted By: Richardl60
Date Posted: 18 Aug 2016 at 7:06pm
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Very interesting Graham. I was surprised to read the end conclusion given what had gone before. Whilst I cannot say it would be a specific issue I do use 1000 ohm on my Dynavector. Whilst it wouldn't be an issue for me whether combined gain was higher or lower than the elevator/accession combo but presumably this would cater for low output Moving coils mine is 0.26 or 0.28mv from memory. Sounds like watch this space then! |
Posted By: Richardl60
Date Posted: 18 Aug 2016 at 7:10pm
| PS as was recently commented on the interconnect link between the elevator/accession will impact on the results and no doubt Graham, Bob etc will have been using your own leads so it is possible this variable could be removed from the equation with the MC stage for other users who may not use these (for better for worse as the saying goes). |
Posted By: DaveG
Date Posted: 18 Aug 2016 at 9:30pm
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hmmmm....interesting that the presumably cheaper 1 box solution could sound the best. Not cheaper for me personally unfortunately as I already have the 2 box in place. I'd certainly like to listen to one and 100ohms is right on the money for my preferred Ortofons anyway. Although I've experimented with different loadings in the 10 years I've owned an EXP, I always return to 100. ------------- Dave Michell Gorbe + HR PSU -> Cadenza Bronze -> SME V -> Elevator -> Accession -> Proprius -> B&W CM6 s2 | Cusat 50 & Spatia cables -> 
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Posted By: Suggs
Date Posted: 19 Aug 2016 at 6:39am
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...hmmmmm indeed. This does sound intriguing as it does seem, as stated by DaveG, to conclude in the opposite way to that which sounded best previously i.e. Reflex M + Elevator is undoubtedly better sounding then the one box Reflex C. My concerns too are over the level of gain compared to the two box set up. In my system I always feel I could do with a tad more overall gain on the phono side of things as the noise level does reach a quite audible level, although easily obscured by music playing. I certainly wouldn't want less gain The other point raised previously concerning cartridge loading is also a concern...I have found the Dynavector to sound best to my lugs with the loading on the Elevator set to either 840 or 1000 ohms. Thankfully, as one of Graham's loaner organisers, I'll be in a position to try these comparisons out for myself, hopefully in the not too distant future  Anyone else in Europe who would like to compare for themselves, let me know by PM and I'll start a queue------------- Derek |
Posted By: Richardl60
Date Posted: 19 Aug 2016 at 7:07am
| Interesting what you say about loading and gain, which Dynavector do you have? |
Posted By: Graham Slee
Date Posted: 19 Aug 2016 at 9:18am
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I will never alienate friends and existing customers by producing something better cheaper. An Accession MC, which is in "beta" at present, would sell for similar as the Elevator + Accession MM. Interestingly some low output Dynavectors work into 30 ohms, so it will be good to have feedback on how the limited impedance range fits with these sound wise. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: ICL1P
Date Posted: 19 Aug 2016 at 9:29am
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Hoping it finds favour so that the GSP Twin Accession may come to fruition. I'll start saving for a 2 x MM version. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: morris_minor
Date Posted: 19 Aug 2016 at 3:20pm
  When Graham asked if I'd like to hear his AccessionMC prototype, I ummed and erred for about 5 microseconds before saying "yes please" . . . I let Graham know some of the music I had and we settled on a few tracks to do the comparisons, plus I sent a few of my own choices. Before the AccMC turned up I ripped the tracks with the AccMM+EXP with most of my selection of MCs - which, for the record were: Zyx R100H, Yamaha MC-1x, Hana EL, Ortofon Rondo Blue, Ortofon Vivo Red. The rips were replicated with the AccMC in place. My Lexicon I-O 22 ADC was connected to the variable output on the Accessions by CuSat50 cables, and to my computer by a Lautus USB. The AccMM and Elevator were connected by a short CuSat50. BTW the turntable was my Kenwood KD7010 direct drive. I made sure I matched recording levels, and the files were saved as FLACs for Graham to download. So much for the procedure - what were my conclusions? Well - the AccMM+EXP is a hard act to follow. (I'll just refer to MM and MC from now on . . ) Both MM and MC showed the different cartridges in the same way - one didn't make a cartridge any worse or better. You get out what you put in, in that respect. It's the presentation that's different - and I was pleased to see that Graham, John & Leo agreed with me that the MC is even more natural and unforced than the MM. A quick A-B comparison could have you favour the MM, because it seemed to me slightly more "hi-fi" than the MC. But the musical communication with the MC was a delight to listen to. Soundstaging, detail, dynamics, depth - they were all first class but in a manner that never drew attention to the way the sound was being reproduced. Rather, all the aspects combined to draw you deeper into the music and banish any thoughts you had about just "listening to the sound". If you have an AccMM+EXP should you go for the AccMC? It raises the bar even higher, so I'd definitely say "audition one" - and pre-warn your bank manger (do we have these nowadays?). Me - I'm going to hang out for the Acc "Duo", able to take both MM and MC inputs. The Reflex can then take the place of the Era Gold V in the living room, and that plus the EXP can be retired (more likely stored for a future system elsewhere in the house . . .  ).I hope this helps . . . . ------------- Bob Majestic DAC/pre-amp Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50 2 x Proprius + Spatia/Spatia Links |
Graham Slee wrote:Posted By: Richardl60
Date Posted: 19 Aug 2016 at 6:21pm
| Thanks Bob very helpful. May end up on my shopping list . . . . . |
Posted By: Suggs
Date Posted: 20 Aug 2016 at 6:15am
It's the DV-XX2Mk2. The recommended load impedance is 30 ohms, but to my ears (and everyone who's heard the comparison here) the sound was relatively flat and closed in until the Elevator was adjusted up to the loading levels mentioned. I have no idea why that should be but it is definitely my conclusion  ------------- Derek |
Posted By: Richardl60
Date Posted: 20 Aug 2016 at 9:37am
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Snap! An excellent cartridge. It is some time since I have read the spec but thought it was a minimum of rather than a stated value? I gradually increased the loading to the current value over a longish period and keep telling myself i should have a play with the loading again but have been too busy enjoying the music of late. It is possible of course that the 500ohm loading in the Accession MC may outweigh the change in loading? Will see but glad we have a common interest/sense of enjoyment. |
Posted By: Suggs
Date Posted: 20 Aug 2016 at 11:58am
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Yes, tg (of this parish) is also a user of the same cartridge...obviously good taste abounds here on the forum (as it would ). If he picks up this post his findings would be well worth reading also. ------------- Derek |
Posted By: tg [RIP]
Date Posted: 21 Aug 2016 at 6:27pm
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My preferred load for the DV was 456 Ohms (1K parallel to 840) - I found that preferable to 500 Ohms and consequently did not try any higher. That was with the Revelation. I have not used it again since receiving the Accession so cannot say if it might change that preference. ------------- Tony G |
Posted By: RichW
Date Posted: 22 Aug 2016 at 10:03am
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Bob - thanks for your impressions of the AccMC, it sounds like a superb piece of kit. Tough decision to make now for existing Accession owners wanting to add MC capabilities to it. Go for the new box at around £1500 (?) or add an Elevator to the Accession MM at less than half that. Having recently heard the Elevator/Accession combo I was set on going that route. ------------- Majestic/Enigma, Accession MM & MC. |
Posted By: Suggs
Date Posted: 22 Aug 2016 at 11:15am
It's an even tougher decision for those who are already Elevator and Accession owners  Do they stick with what they have or go the one box route? It remains to be seen (heard?) whether there are any sonic advantages and, if so, will they be worth the extra financial outlay...let's wait and see ------------- Derek |
Posted By: morris_minor
Date Posted: 22 Aug 2016 at 11:56am
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As an upgrade from a Fanfare or Reflex C, the AccMC would be a no-brainer. For AccMM+EXP users I'd say an audition is a necessity. Everyone will have their own ideas about how much the extra outlay is worth it. Plus the general scarcity of GSP gear on the secondhand market should mean that if you want to move kit on to finance a new purchase you should get a good price for it . . . ------------- Bob Majestic DAC/pre-amp Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50 2 x Proprius + Spatia/Spatia Links |
Posted By: Richardl60
Date Posted: 22 Aug 2016 at 2:56pm
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Yea Bob the forum or eBay should be able to move (loved but) unwanted gear on Whilst my colours are nailed to the moving coil mast the other variable for some could be that if buying the acc mc then back to MM could be more tricky. At present I can unplug the elevator. |
Posted By: morris_minor
Date Posted: 22 Aug 2016 at 3:42pm
------------- Bob Majestic DAC/pre-amp Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50 2 x Proprius + Spatia/Spatia Links |
Posted By: BAK
Date Posted: 22 Aug 2016 at 4:52pm
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Seems we need to keep Graham busy! ------------- Bruce AT-14SA, Pickering XV-15, Hana EL, Technics SL-1600MK2, Lautus, Majestic DAC, Technics SH-8055 spectrum analyzer, Eminence Beta8A custom cabs; Proprius & Reflex M or C, Enjoy Life your way! |
Posted By: Richardl60
Date Posted: 27 Aug 2016 at 11:50am
| Not sure quite what Graham's line of thought is on the Acessions duo/MC but if this had an inbuilt upgrade ability it would be helpful. Whilst I don't have any perceived need for duo or MM only option a box with the ability to would be good for some? |
Posted By: Graham Slee
Date Posted: 28 Aug 2016 at 9:04am
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@ Richard et al, from a manufacturing point of view it is sensible to make the MM and MC inputs as plug-in cards, or at the very worse (but good for connectivity) modular cards with solder-in flying leads. The former would make it "user configurable", being able to swap one type of card for another. We're only talking about a small section of circuitry, but it is an important part because it does all the required gain to lift the signal out of the noise as well as the cartridge EQ. Another thing it will require IMO is section level matching for those wanting to do direct comparisons between cartridge types - thus requiring a potentiometer per input (after each gain stage). In my opinion these would feed a summing junction, and have a mute switch each, such that the unused input noise would be removed. By combining these mutes into a single switch it would be cross-mutable such that with a two arm turntable AB comparisons could be made. The savvy reader will now be able to jump to the conclusion that with a centre-off "cross-mute" the thing becomes a turntable mixer, albeit an expensive one. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 28 Aug 2016 at 10:30am
| Sounds perfect Graham. |
Posted By: Suggs
Date Posted: 29 Aug 2016 at 7:02am
All of Graham's products sound perfect ------------- Derek |
Posted By: ICL1P
Date Posted: 26 Nov 2016 at 10:44am
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Graham, how is this project progressing? ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Graham Slee
Date Posted: 27 Nov 2016 at 6:46am
Quite a few projects took a back seat this summer whilst building work took place, and summer became autumn, and very soon it will be winter (in approx. 3 days...) Frustratingly the build process didn't fall into the neat little boxes I would have preferred, and the finishing off jobs became awkward. The listening test "environment" changed from having stud wall dry-lining to dot and dab on masonry, and I can hear the differences. Even the chair I bought isn't doing me any favours. Hopefully in the next few days all the niggling tools and materials will be tidied away to make way for progress to happen. The differences between the MM and MC input stages are considerable, and I still don't understand how anybody can make a "one circuit does all" - technically it doesn't make sense (although to a simple mind it may do). The MC input has taken some getting right. It being an inverting integrator having an inverse frequency response to that of a cartridge - plus input impedance (which the Dynavector patent doesn't have), it should be unique (let's hope the patent engineers agree...). And because it's unique it requires solutions nobody has done before. It isn't what the technical bystander's mind-set might think, and so there have been new challenges to overcome. Technically we can hark back to the OP37 op-amp data sheet which acknowledged the possibility of cartridge magnetisation because of input bias current: the silicon valley engineers incorporated bias current cancellation circuitry to minimise the issue - but even so some bias current must happen, so cancellation is the wrong word - it is vastly reduced but not non-existent. That is what DC coupling brings: bias current flows in the cartridge full-time. AC coupling, so frowned upon by the misguided, at least removes DC current from the cartridge. The integrator uses an FET input op-amp because the large signal gain of the integrator requires a high impedance feedback circuit, and so the bias current at the input is minute. Therefore the essential input coupling capacitor which must be large in value to pass undistorted low frequencies, has to be electrolytic. A GP electrolytic has more initial leakage than the input bias current and so will never switch on. Those suitably qualified will know how I worked around that. What I have to do now is replicate the existing circuits in a overall system which also includes an output stage which can swing voltages in excess of what most op-amps can do. Why? Well, because quite a lot of my customers insist on valve amplification (and have never heard the Proprius, and won't, because it doesn't have valves...), and valve amps need such a high input voltage (having these days been designed for CD player hot outputs). To obtain that signal voltage swing cleanly, so it never clips, requires more headroom than a +/-18 volt rail will allow. This might well be the stumbling block. The power substructure required to bootstrap an op-amp output stage to deliver the voltage swing might dictate DC coupling, which is a nightmare in itself. Added to that is the intermediate voltage regulation necessary to reduce the power supply voltages for the input stages - voltage regulation always relies on zener diodes one way or another, and I don't want any because I can hear what they do to the sound. Unfortunately zener diodes exist in op-amps and voltage regulators, and it's my belief that as far as op-amps are concerned, that it is the degree of zener isolation which makes one op-amp sound different to another, and not the crazy talk you hear on some forums. Discrete transistor circuits can be made zener free, but will never perform at preamp level as good as the op-amps I use. Therefore there will be quite a bit of contemplation on the matter to obtain the right solution. As always, the sound dictates all. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: ICL1P
Date Posted: 27 Nov 2016 at 9:39am
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Thanks for the update. It sounds as though there's a bit more to do than previous posts suggested. ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Graham Slee
Date Posted: 27 Nov 2016 at 11:39am
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There will always be a bit more to do ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Paperweight
Date Posted: 19 Mar 2017 at 1:39am
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Valves are nice but I think some people are too fanatical about them. Next thing you know, someone will ask for a valve phono pre. |
Posted By: Graham Slee
Date Posted: 06 Jul 2017 at 8:53pm
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At this point the conversation drifted onto the proposed Accession Duo and it was felt a new post should be started to save confusion. See: https://www.hifisystemcomponents.com/forum/accession-duo_topic4263.html#52862" rel="nofollow - https://www.hifisystemcomponents.com/forum/accession-duo_topic4263.html#52862 This topic continues on the Accession MC ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: morris_minor
Date Posted: 07 Jul 2017 at 10:11am
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Good idea to split off the duo conversation . . . How imminent is the AccMC? I'm sure lots are dying to know . . . ------------- Bob Majestic DAC/pre-amp Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50 2 x Proprius + Spatia/Spatia Links |
Posted By: ICL1P
Date Posted: 07 Jul 2017 at 10:19am
3rd July '17 [QUOTE=Graham Slee]Talking about the Accession, it is now available in a moving coil version as well as the existing MM original. I will let you know when its web page goes live in a week or so.[QUOTE] ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Aussie Mick
Date Posted: 28 Aug 2017 at 1:05pm
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Hi Graham, Is the Accession MC now available? Have I missed something? Mick. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: Graham Slee
Date Posted: 29 Aug 2017 at 6:16am
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I hit the 'emergency stop button'. I was just about to write the description and about the sound with headphones on, as I do, and... Honestly, I didn't recognise what I was hearing. I heard Kazoos instead of Sax. I heard loud crackles instead of quiet record noise. My mind could not reconcile any of this: John had told me about all the favourable feedback he'd had from early adopters. The stage I was running was the same R&D unit which had behaved so well for so long, several months in fact. It stopped me dead in my tracks. Could it be that I'd worn out the Denon DL103 I'd been using as regular auditioning cartridge? I ordered a new one on the spot! Expecting next day delivery advertised by its seller, it didn't arrive. Neither did it arrive the next day or the day after. Then another thought occurred to me. Maybe the arm bearings were at fault? The turntable was replaced by another from stock. There was a bit of improvement using the existing Denon DL103. I didn't want to swap out for a different cartridge because it takes so long to get used to a different sound, and I started worrying about the age of the alternatives I had too. With no sign of the Denon DL103 and a email from the supplier apologising explaining that one had been ordered direct from the manufacturer, I decided in a rash moment to buy a Hana EL - which I did get next day. The other day the Denon DL103 turned up. Installed and in play it sounded much different but now it has to run-in, and so does the Hana EL. As with all my designs they are only realeased when they continuously make me happy, and I'm demanding in the extreme. Add the fact that I'm not convinced that moving coil gives a true rendition of any of my music and is only for special audiophile music - simple stuff like Fremer played in his recent test - and it takes a long time to convince me of anything. £1200 is a lot of money from a customer's standpoint. Multiples of that amount having to be refunded is a rather large risk I'm not willing to take. I would rather scrap the thing and do without. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Graham Slee
Date Posted: 29 Aug 2017 at 9:37am
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Put it this way: it has to play Brain Salad Surgery by Emerson Lake and Palmer without causing convulsions! ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Aussie Mick
Date Posted: 29 Aug 2017 at 9:43am
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Thanks, Graham, On the one hand, sad face. On the other, we all know how good the Elevator is. You're still winning. All the best, Michael. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: ICL1P
Date Posted: 30 Aug 2017 at 7:55pm
Does this mean it's not going to materialise or that it's back in the design phase? ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Graham Slee
Date Posted: 30 Aug 2017 at 8:33pm
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Abandoned ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Graham Slee
Date Posted: 30 Aug 2017 at 8:35pm
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I am currently enjoying getting my hearing back using a 2M Black and 11 year old Gram Amp 2 (the original Communicator). What a relief! ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Drewan77
Date Posted: 30 Aug 2017 at 9:37pm
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This latest confuses me (which isn't difficult!) - if the Accession MC is abandoned I guess this means that it sounds inferior to the MM version + an Elevator? Or is it that Graham does not believe that any MC cartridge/phono could sound superior to a high end MM/MI? ------------- Older than I once was, younger than I'll be ............................. Andrew |
Posted By: Graham Slee
Date Posted: 31 Aug 2017 at 1:52am
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MC cartridge outputs are in the range 0.1 to 0.7mV and electrically can reach 2 MHz. Because of their constant velocity character the output rises at 20dB per decade, and distortion products reaching 2MHz (no music signal up there) would be 66dB higher which equates to 600mV for an average 0.3mV 1kHz rated output. There will be distortion products because the vibration system encounters friction as well, and also electro magnetic interference which is not effectively screened by the archaic tone arm electrical characteristics. At the opposite end of the spectrum the output at 10Hz is a mere 0.03mV, or 30 micro-volts. The type of electronics required for both low noise to allow 0.03mV a reasonable signal to noise ratio, and input natural slew rate of 11V/uS to cover the ultrasonic artefacts is extremely limited. There is enhanced slew rate which is better termed forced slew rate which occurs in their output stages, not naturally in their inputs. The input slew rate is nothing like the quoted slew rate. Slew rate equals 0.3 x Ft in a differential amplifier (or an op-amp) and for a 10MHz gain-bandwidth product amp it is 3V/uS. Insufficient for an 11V/uS input possibility. This can be improved only by emitter degeneration in a BJT amp, or through the use of input FETs. In both cases there is a noise penalty. There are however two FET input op-amps that exist which should be capable of doing it, but they both feature enhanced (forced) output slew rate. There are also three other BJT op-amps which feature enhanced slew rate which could be used. The OP37 is a decompensated version of the OP27 and is only unconditionally stable if compensated to be an OP27 and so has a slew rate of just 2.8V/uS. Unsuitable. The NE5534 with unity gain compensation is 7V/uS. Almost suitable you would think, but (difficult to find) applications data puts its real input slew rate at just 0.5V/uS. A particular video op-amp is much faster at 230V/uS and uses a different type of enhancement which is cumbersome to stabilize unless most of the enhancement is given up by overcompensation. It will manage the required input slew rate. However its input current is far too high for the size of feedback resistor required, so it is a non-starter in many ways. This leaves the two FET devices: OPA827 and AD4627. Note they end in 27. It's because they are FET input variants of the OP27. All five op-amps are three stage devices to obtain the open loop gain they possess. The third stage has to use enhancement techniques to reach the gain bandwidth product such a high open loop gain dictates whilst maintaining their -20dB per decade slope. In the case of the OPA827 and AD4627 they share the same enhancement as the OP27. Their slew rate is an FET input multiple of 2.8V/uS. But if you take the 8MHz gain bandwidth product of the OP27 and apply the slew rate formula you will note it should read 2.4V/uS. This is indicative of output slew rate manipulation or enhancement. If the two FET input op-amps did not have this enhancement we would be left with a good natural input slew rate suitable for MC, but it is necessary in a three stage device, and so the result will be distortion. In fact, simulation shows ultrahigh frequency instability if used as suggested by their respective manufacturers. Through noise gain manipulation these op-amps were made to stabilise by tricking them by increasing their gain without changing the signal gain. However, any increase in gain reduces the bandwidth, and in reality this reduces the true slew rate. In all cases there is slew induced distortion set off by the many high frequency artefacts including the mixing-in of noise and the ever present radio frequencies introduced since the early days of low output moving coil. This is evident on listening as 'new' or alien sounds are produced especially but not limited to the upper mid band. We could always reduce the input slew rate presented to the range of possible amps. It could be limited in frequency by adding input capacitance to the stage. But where do you set it? The cartridges I'm using range from 12uH to 56uH inductance, and from 8 to 43 Ohms equivalent series resistance. Some such as the SPU's will have lower inductance and I'm sure there will be one or two MCs with higher inductance. The range is something like 5:1, whereas with MMs it is less than 2:1. This smells of cheating. We may as well have tone-controls, but that is a taboo, and so is frequency limiting. I know it is used in some MC phono stages, and remember a discussion by one well-known designer suggesting the use of a 10nF load capacitor. If it were only that simple. Capacitors come with inductance which competes with cartridge inductance to produce frequency spikes, which if they happen in the wrong place ruin the sound. It would be unfair for one or two MC cartridges to carry the can for this. So what is the solution for MC users? They could switch to MM where these problems don't exist, or don't exist to such extremes. The alternative could be to use a device which can make use of a particular video op-amp, overcompensated as it has to be, but with much lower gain which makes it viable. So what device is that? The Elevator EXP moving coil step-up amplifier! PS. Please do not write in with your suggestion of op-amp. I have been there, bought the tee-shirt, and it shrank. And after 40 years of doing this I'll not be very happy about others trying to tell me how to do my job. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 31 Aug 2017 at 7:18am
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Thank you for the detailed technical summary graham. In summarising I read this as the MC concept is a fundamentally flawed design (or at least has sufficiently big holes in it to render it inferior to the listener than mm) which may be overcome with the MC accession if there was suitable electronic devices to accommodate it which there isn't? There appeared general agreement from the mule device last year that it sounded better than the accession m & Elevator? Were those initial conclusions erroneous or has something else changed? |
Posted By: Graham Slee
Date Posted: 31 Aug 2017 at 10:06am
I don't think it could have been used for long enough or with sufficiently diverse material to have resulted in a true opinion. Having lived with the device and in its many forms for close to three years, and playing such an eclectic mixture, ocassionally reverting to MM gave a "breath of fresh air" which had always been telling me of my folly. I think by now I must have proven beyond all doubt that MC is a concept which never considered how it would be used. Such concepts don't exist in the real world, only in make believe... ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 31 Aug 2017 at 11:32am
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So the best way of upgrading from my Dynavector MC would likely be to buy a far cheaper mm/MI, sell the Elevator and raise some cash in the bargain too, sounds appealing. Does beg the question what is 'the best' no expense spared MM/MI out there? Arms are of course interact with the cartridge and some may be better suited to certain cartridges than others and my current arm is probably best suited to MM already. |
Posted By: RichW
Date Posted: 31 Aug 2017 at 12:59pm
Sticking my neck out I'd say Len Gregory's MusicMaster MI is a top contender. ------------- Majestic/Enigma, Accession MM & MC. |
Posted By: Graham Slee
Date Posted: 31 Aug 2017 at 3:40pm
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The points to understand are: 1. A cartridge is a signal source in series with an inductor (its coil). Therefore any signal appearing in series with it is treated as being a signal from the cartridge via this inductor - even after it because you can stick the signal source either side for a series connection. For the sake of simplicity we will include only the signals appearing in series before the arm interconnect, assuming the arm interconnect to be properly shielded such that no signal appears on it, and thus the signal area is the wiring in the arm up to the cartridge and the cartridge itself. 2. Electromagnetic waves appear as signals in this area. 3. Tone arm shielding is only effective to 30MHz based on a 9 inch arm. Therefore any frequency beyond 30MHz can be a full size electromagnetic wave in series with the inductor. And frequencies below this will only be partially attenuated and not blocked. 4. An inductor and capacitor in parallel form a tuned circuit identical to a ferrite rod aerial in a basic transistor AM radio. 5. The cartridge is an inductor and the arm interconnect is a capacitor. 6. The output of a constant velocity device rises with frequency. The cartridge plots you see are 'normalised'. The output of the cartridge is increasing at a rate of 20dB per decade and will continue doing so until the circuit becomes capacitive where the output will fall. 7. At the point where the inductance and capacitance are in equilibrium that is the tuned frequency. 8. Calculating for the inductances and tone arm interconnect capacitances used in moving coil we find the tuned frequency is in the region of 2MHz which is in the short wave radio band. 9. Slew rate is given by 2pi x peak voltage x frequency, and hence the signal slew rate presented to the amplifier input is beyond the capabilities of most audio preamp level inputs. Unless the input signal is heavily filtered the amplifier stage will seriously distort at its slew rate limit. This is generally beyond the audible spectrum, and as such all electrolytic capacitors (in the power supply too), as well as other capacitors other than perhaps high voltage polypropylene and polystyrene capacitors will be operating outside their range. 10. Without the stability afforded by these components the amplifier stage will be unstable and the output will be severaly distorted at high frequencies. The distortion and other harmonics mix the same way as radio mixers work to produce a new frequency, or set of frequencies which never existed until this point. These will be mostly high order and the result is masking of low to mid frequencies by high frequency 'hash' resulting in an artificially bright sound. 11. The input slew rate should therefore be limited but the choice of filter frequency will not suit all moving coil cartridges, which vary in characteristic by a ratio of getting on for 5:1. 12. As in 8 above, the MM cartridge produces a tuned frequency of around 16kHz when loaded into approximately 200 pf which is the arm cable and phono stage input capacitances lumped together. 16kHz is nowhere near radio transmission frequencies and so the input slew rate presented to the preamp is easily handled and little distortion is produced at the amplifier output. 13. Because of the tiny signal at low frequencies the MC cartridge produces it can easily be masked by circuit noise, calling for a low noise amplifier, but low noise is achieved through low speed. Which means the slew rate is severely limited exasperating the distortion problem. 14. MI and high output moving coil have far lower inductances than MM which tunes them to somewhere in the long wave band, so they too can cause the slew rate to exceed the preamp input slew rate, and distortion results. But not to the extreme caused by MC. You would have thought that the designers of moving coil would have considered how they are interfaced with the audio system, but it appears they did not. And to be fair early devices were introduced in the valve era, and as valves are too noisy for direct electronic amplification of such low signal levels, a transformer was always used to step up the signal. The supposed benefit was their agility in being able to track. Today the MM can track and easily pass most test disc obstacle courses. Which begs the question why MC? And because I've basically been saying the above for many a year it has not earned me many friends in the hi-fi trade. My business could have made a lot more money pandering to the MC whim, but for me it is about the music and how it can be made to sound real, before monetary considerations. And lastly some bright spark will ask why don't other mediums distort in a suchlike manner? That is because other sources have finite slew rates. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Drewan77
Date Posted: 31 Aug 2017 at 7:19pm
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Thank you for that last summary Graham & putting it in laymans terms for us. I now understand what concerns you and why you will not continue along this path given the vast permutations of possible cartridges and tonearms. ------------- Older than I once was, younger than I'll be ............................. Andrew |
Posted By: Fatmangolf
Date Posted: 31 Aug 2017 at 8:13pm
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Next time I can I'll swap back to my 1042 which had a new stylus recently and see how it sounds. I'm not averse to a breath of fresh air but must say I do like the sound of my MC cartridges through your EXP and Accession. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: Graham Slee
Date Posted: 01 Sep 2017 at 2:52am
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The Elevator EXP was not without its problems. Initially I had wanted to use discrete circuitry but it gave rise to all the problems illustrated plus actual rectification of interference, which discrete still does but now to a larger extent because the number of sources of interference has grown over the years. I have seen junction FETs used instead of bipolar transistors and have been quite amazed that noise doesn't obliterate the signal, and a respectable S/N ratio has been possible. However, when taking measurements of a commercial unit the upper sine wave frequencies progressively became triangular before reaching 20kHz. This is indicative of a large amount of slew rate distortion which a 1kHz THD test conveniently ignored. Op-amps were surveyed for the lowest noise and highest slew rate. I ignored the usual low-noise op-amp choices because these exhibited considerably small slew rates. Slew rate is the measure of the ability of an amplifier to react. An amplifier's output with a low slew rate when hit by a fast signal (read: high frequency with a sharp rising edge when I say fast) will not rise in sympathy. Only part of the signal will have risen - a form of attenuation. Therefore some part of the music is effectively blocked, and the result sounds distorted. THD being steady-state ignores it. Therefore fast op-amps were chosen. A handful fitted the bill and were prototyped for audition. Out of those the best sound in my opinion was from the OP37 and a particular video op-amp. Both were painful in the extreme to stabilise - to prevent them oscillating - and required a lot of 'lateral thinking'. Having studied mathematical modelling helped. The OP37 version was sold as the Elevator, and the video op-amp version as the Elevator EXP. The EXP version was the customers preference and the OP37 version was dropped. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: RichW
Date Posted: 01 Sep 2017 at 9:03am
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Thanks for sharing your experience & taking the time to explain the engineering involved in designing a competent MC phono stage. ------------- Majestic/Enigma, Accession MM & MC. |
Posted By: morris_minor
Date Posted: 01 Sep 2017 at 6:30pm
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I've just caught up with this thread - and am sad to see the AccMC abandoned. But I respect Graham for sticking to his principles and not releasing what he considers an inferior product not up to the universal standards of the rest of the range. ------------- Bob Majestic DAC/pre-amp Accession MC/Enigma, Accession MM, Reflex M, Elevator EXP, Era Gold V Solo ULDE, Novo, Lautus USB and digital, Libran balanced, CuSat50 2 x Proprius + Spatia/Spatia Links |
Posted By: tg [RIP]
Date Posted: 02 Sep 2017 at 5:14am
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Wot he (Bob) said. Mind you, it is somewhat reassuring to know that I already have the best possible. ------------- Tony G |
Posted By: ICL1P
Date Posted: 02 Sep 2017 at 9:01am
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Presumably the abandonment of the Accession MC kills off the development of a twin stage box. I had been hoping for a twin MM, switchable between two TTs to feed my Majestic. I suppose I'll have to continue with a switch box and if I want better and prettier than I have (rek-o-cut) I'll probably have to take Bob's advice and buy something from Dodocus. Of course I would prefer a Slee switch. Anyone else out there needing to feed multiple analogue sources into a Majestic? ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: Graham Slee
Date Posted: 03 Sep 2017 at 5:27am
Thought I'd upload the curves: RIAA response follows prescribed curve within 0.3dB right out to 100kHz then after falls off such that there are no EMC disturbances. Graph extends right out to one trillion hertz which is down 400dB or 1x10-20.  This is further proven by the input stage which is an integrator which equalises the cartridge response for the majority of the audio band. Stability is excellent with 100 degrees phase margin and more than 40dB gain margin.  The bit which does the actual mid frequency record response: 500Hz to 2122Hz (RIAA). Again stability is excellent with 95 degrees phase margin and over 40dB gain margin. So, why do MC manufacturers make cartridges sound so piercing? Maybe my electronics are too good? And if so... ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Graham Slee
Date Posted: 04 Sep 2017 at 9:39am
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Seeing I've abandoned it I thought I'd have another 'play' Last post I said "Maybe my electronics are too good?", and I promptly found out they weren't because I spotted the possibility of some oscillation due to the inductance of a capacitor used to stabilise the reference voltage of the input stage op-amp.  The thing about simulation is it will tell you what you want to know, and if you don't model things accurately it won't give you accurate results. The only way around this was to add series resistance, but too much and you have zener noise modulating the signal which sounds bad too. Having done that my attention turned to noise gain stability again. The stage was stable as the earlier curves show - see curve two. However, the degree of negative feedback to the input - this being an inverting stage - wasn't much up at the 2MHz tuned frequency exhibited by MCs. OK, there is no audio signal up there, but there is something, and by reducing noise gain such that there is more negative feedback which means the virtual earth is more 'zero' up at 2MHz resulted in a positive audible improvement, especially with the Hana cartridge. By the way, I'm back on the ADA4627 op-amp seeing it must be the last op-amp on the planet capable of doing this work. Although there is no schematic illustration of it on the data sheet I am sure from its characteristics it is an FET input OP27, and by adjusting the noise gain for a GBW of 8MHz, which is what the OP27 does, improved it further. At its rated 19MHz the phase margin is quite slim at around 58 degrees (this design), but manipulating noise gain for 8MHz gives 80 degrees. OK, it's not the 90-plus degrees I like to go for, but as I said above, it looks as if the virtual earth or ground needs to be "more zero" at 2MHz, and pushing it out to 8MHz ensures that. 80 degrees is stable, and the op-amp manufacturers insist 45 degrees is stable but I beg to differ, but 80 degrees will I suppose do. Gain margin is about 30dB which is better than the 20dB you'd get without noise gain. So then I had a workings out session on slew rate. 8MHz using a non-degenerated bipolar input works out at 2.4 volts per micro-second (SR = 0.3 x Ft), which would be right for an OP27, but for the fact the manufacturer claims 2.8V/uS. So it looks like the ADA4627 works best manipulated like an OP27. The equation should really state SR = 0.3mFt where m is the degeneration, so there must be some slight degeneration in an OP27 (degeneration is mainly good by the way). An FET input also has some degeneration which is factored into m, and m can be obtained by manipulating the equation, but I will not bother you with that. It is approx. 13 or 14 for an FET input, so if we got 2.4V/uS, we multiply that by say 14 and we get 33V/uS, and that is the input slew rate we now have. If you remember a few posts ago I said an MC cartridge would need around 11V/uS, then 33V/uS is going to be good. The only thing about noise gain is it adds noise (hiss) so the result isn't going to be silent. It isn't going to be in your face either, but there will be some. Putting it on the analyser I found S/N measured 63.5dB, which if you add the gain gives about 125.5dB equivalent input noise (EIN), which isn't bad, but isn't the best you'd get. The best is around 130dB so we're around 4.5dB worse. If you consider 3dB is double the power, then 4.5dB is going to be noticeable, but I can live with that. Have you ever heard a live band? Maybe not these days (because it's all digital) but not so long ago you could hear the hiss when they set up and got the PA ready. Well, the hiss isn't going to be that loud, unless you use a 0.1mV output cartridge. It now sounds a lot better. MC has been tamed a different way, and without an input filter because input filters kill the cartridge's inherent slew rate. So has it been un-abandoned? We'll see. I'm not rushing into anything. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 04 Sep 2017 at 1:43pm
| Will watch with interest. |
Posted By: Aussie Mick
Date Posted: 04 Sep 2017 at 1:51pm
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Too late! I've ordered an Elevator EXP and I'm positive I'm going to be a very happy camper. Mick. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: Graham Slee
Date Posted: 04 Sep 2017 at 2:20pm
Of course you are!  ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Aussie Mick
Date Posted: 04 Sep 2017 at 3:00pm
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It's far too late for this, Graham! Midnight here and still in the throws of winter, despite being four days into spring! Thank goodness for the medicinal warming of Laphroig Quarter Cask. Mick. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: Graham Slee
Date Posted: 29 Oct 2017 at 3:01pm
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Nearly two months on and the early adopters of the AccMC seem quite happy with them, and John C received glowing praise from one customer... ...but it was not my kind of music reproduction. Since then I posted Understanding Record Repro, and uncovered the sheer level of interference on the cartridge wiring and took photos of the scope displays as evidence. The level of interference was same for MM and MC, busting the myth that MC is largely immune to that sort of thing because of its low inductance. My conclusion was the character of the sound was being influenced by the interference, which is relatively 10 times what it is using MM. And with MM I don't get the same characteristic. I played around with many kinds of filters to no avail, and I eventually had to conclude that the level of interference was somehow mixing with harmonic distortion at really high frequencies, and by a process known as heterodyning, was making different audible sounds to what my ears expected. I decided to try and 'kill' the highs by making a pre-preamp or head amp stage to preceed the MM version of the Accession. Making the head amp such that its high frequency performance isn't manipulated like op-amps do. I found that the modern ADA4627 and the ageing NE5534 shared slew rate enhancement, which basically made matters worse, so it needed something which would do high frequencies 'naturally'. Having made (or cloned) just about every idea ever imagined by all kinds of audio electronics professionals, I knew that going there again would be fruitless. So I simply took one low noise transistor - a medium power device often used as pre-driver in power amplifiers - and made a simple single transistor pre-preamp out of it. The result? Incredibly better! How does it measure? Almost just as good! The prototype of this has been running now for just over a week, and so far the sound - the sound I can live with that is - has not took a turn for the worse. It might now be the time to un-abandon it. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: ICL1P
Date Posted: 29 Oct 2017 at 5:33pm
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Good news! ------------- Ifor ===== Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair. |
Posted By: BackinBlack
Date Posted: 29 Oct 2017 at 7:05pm
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Good news indeed, soon we might all be able to hear how an MC really sounds. ------------- Just listen, if it sounds good to you, enjoy it. |
Posted By: shashirao
Date Posted: 01 Nov 2017 at 1:19am
| So do I wait for the Accession MC...or indulge in an MM cartridge...been eyeing the ClearAudio Charisma v2 |
Posted By: Graham Slee
Date Posted: 01 Nov 2017 at 7:18am
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Although I am a vinyl fanatic I am also a realist. Vinyl and other substrates used for the purpose of cutting a mechanical representation of a musical signal cause problems. Not that it's the substrate's fault, but the very thought that it will reproduce music perefectly is absurd. My early career was in mechanical engineering and I was also a motorbike racing fan, often marshalling at Cadwell Park. It taught me of the shortcomings of things having spring-like nature, and vinyl is no different. When spring-like things have to negotiate too many things at once they throw a "tizzy", and that's true of many things whether it's valve bounce on an over-revving engine, a bump on an off-camber bend on a race track, or a number of peaking signals at some point in a recording on vinyl. Moving coil is made so 'pure' that when it encounters a "tizzy" situation, it exposes it big-time, and that isn't music eminating from it - it's gross distortion. An MM might smooth it over - it's not as accurate but it may offend the ear less. "Horses for courses" ( https://en.wiktionary.org/wiki/horses_for_courses" rel="nofollow - https://en.wiktionary.org/wiki/horses_for_courses ) ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Fatmangolf
Date Posted: 12 Nov 2017 at 9:15pm
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Graham I've just put a 1042 MM cartridge back on my main turntable and see what you meant about MM sounding right. I am missing a little detail compared to the MC but it would have been ten times the list price of the Goldring. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: Richardl60
Date Posted: 13 Nov 2017 at 6:28am
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Interesting concept over sounding right. When I auditioned phono stages I opted for the EGV and recall the key feature was it sounded right. Similarly with the cartridge, my Dynavector with the same result. Whilst i am sure it is a Different model to yours my recollction of the transfiguration I auditioned didn’t soun£ right whilst being open and airy. I have had the same impressions with speaker cables some years ago. The key feature not sounding quite right in my experience I’d a slightly odd upper mid/detached and out of Focus lower treble. Not sure whether this reflects your own and Graham’s observations re the type of sound but the acid test would be when yo7 switch back? |
Posted By: Fatmangolf
Date Posted: 13 Nov 2017 at 1:13pm
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It is personal taste, I like the Phoenix's sound especially with the 100 ohm loading and recently the extra 4n7 Graham suggested. The cart was second hand and I wanted to see how an affordable MM like the 1042 compared. Better than I expected but the Phoenix will be back on before too long! ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: RichW
Date Posted: 13 Nov 2017 at 3:18pm
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I must admit, my current racehorse, an Ortofon Cadenza Blue MC, with my 3 week old Elevator EXP into Accession is producing some very fine sounds. The best I've heard. ------------- Majestic/Enigma, Accession MM & MC. |
Posted By: Aussie Mick
Date Posted: 14 Nov 2017 at 6:01am
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I’m torn on this! My 2M Black/Reflex M sounded terrific, especially on rock and pop. However, my Apheta 2/EXP/Reflex M is easily superior in terms of detail, openness, dynamics and colour when I listen to classical and jazz records. However, I can also hear the upper midrange/lower treble glare and ‘not right’ thing people talk about. Balance of virtues, for the music I listen to most, I’ll take it. Mick. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: shashirao
Date Posted: 18 Nov 2017 at 4:51am
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Finally got the first of my MM cartridge - the Ortofon 2M Black. Was eager to explore MM since all carts I own are MC. It was also the first time for me to try the Accession on its own - without the Elevator Stepup. This cartridge has had only around 20 hours of play. The first thing that I observed is the clarity of vocals...the vocals sound more real, as they should be. Some of my CBS recordings play shrill on MC carts to the point of actually sounding raspy. All that is gone with MM cart. The Accession was the common component. The next thing to observe is the stunning quietness in the background...the Accession and the cartridge pair perfect to remove many of the vinyl media disturbances...hiss, crackle, etc. The focus is totally on the music. And then came the realization that the detail is missing. More than missing they also sound overlapped. I can no longer listen to the detail of a specific single instrument. The 2M Black bass is just right and soundstage quite detailed. However there is that sense that none of the instrument stand out. The tracks sound effortless and easy on the ears. I can keep listening to this setup casually. However when compared to the mono MC cartridges, this setup sounds lacking. Of course it is still early days, I need to give the cartridge more time to settle down...maybe another 40-50 hours. The Accession is purring perfect....pair it with any cartridge...its baseline quality is guaranteed...no more noisy playback...clarity of sound, accurate reproduction. I am hoping to receive my Clearaudio Charisma v2 in another 3-4 weeks...till then...I will wait for the Ortofon to settle in.
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Posted By: Graham Slee
Date Posted: 18 Nov 2017 at 7:25am
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Move a tiny magnet in a massive coil or move a small coil in a large magnet; they both have problems. A big coil has high inductance which gives a subtle boost to the highs because the wiring from cartridge to amplifier input always has capacitance which tunes it that way. A small coil on a stylus cantilever is mass on the end of a spring; it resonates in the highs (thank you to "OrtoFan" for the lead...). So are the details really real? ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Fatmangolf
Date Posted: 18 Nov 2017 at 8:22am
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That's the way to get the high treble along with the L/CR input loading you explored earlier. I suspect there are plenty of audible artifacts from the transducers of either type. Hearing your ceramic cartridge a few years back was a real ear opener for me Graham. My return to the MM pond will be coming to an end soon and my expensive when new MC will be going back onto the tonearm. I will probably be refitting my Phoenix via the excellent Elevator EXP with 4n7 loading this weekend. I am mindful of the lifespan of the cantilever suspension which is inside the MC and not replacable as part of an MM cart's stylus unit. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: shashirao
Date Posted: 18 Nov 2017 at 4:10pm
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Is there a thing called aural placebo? :) :) With so many variables in the audio setup from the cartridge to pre-amp to eventually speakers. A shift in any variable may change the sound. To compound the issue even vinyl labels sound different...a CBS recording has its own style compared to EMI or Columbia. And then there is the absence makes the heart grow fonder scenario. It takes me an hour or more to set up a cartridge. Even if I memorize certain sounds, passages, by the time I have the other cartridge installed, my comparative skills have eroded. The previous always sounded better Till date I have rarely played my music over the amplifier/speaker route. Still focused on archiving - and thus I have multiple versions of my core collection....the Revelation-Presentation, the Accession-Miyajima Zero, the Revelation-Kansui, Accession-Cadenza, Accession-Presentation...and now Accession-2M Black versions. Playback for comparison has resulted in a certain setup being ideal for a specific album. I have not found the magic standard one-fits-all formula yet. Maybe I am really not seeking that answer since I am happy doodling various "solutions". The only thing that has remained a constant have been the turntable (xTension), pre-amps (Revelation C now Accession) and cables (Lautus). Maybe it is time to move on to amplification (Proprius) and speakers...
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Posted By: Aussie Mick
Date Posted: 19 Nov 2017 at 8:10am
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Definitely give the Black more play time! When I got mine I thought it had settled around 50 hours in. Then I got better balanced more detail and less noise. Mick. ------------- Rega RP8 - Apheta 2 - Accession MC Enigma PS -Solo ULDE (Focal Utopia) - PS Audio M700 - Fical Kanta No2 |
Posted By: shashirao
Date Posted: 19 Nov 2017 at 8:25pm
| Thanks Mick...I think I do need to wait for the 2M Black to settle in. Yesterday I was doubting my cart alignment because the sound was dense and noisy. The vocals are perfect...the music seems to be getting lost in detail...almost overlapping. Will re-check the alignment and test it for another 20 hours....hoping it will offer MM nirvana. |
Posted By: Drewan77
Date Posted: 19 Nov 2017 at 8:40pm
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That has certainly never been my experience when I used the 2M Black with an Accession Shashi (maybe the TT arm is slightly tail-down which would thicken the sound?). If anything I found the Ortofon to have quite a bright, detailed sound. ------------- Older than I once was, younger than I'll be ............................. Andrew |
Posted By: Fatmangolf
Date Posted: 19 Nov 2017 at 10:34pm
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I would sSecond that suggestion - tail down or a slightly high VTF would have a similar effect on the stylus rake angle. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: shashirao
Date Posted: 20 Nov 2017 at 2:56am
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Thanks Andrew and Jon - I spent a few more hours working on improving the cartridge alignment till my eyes are all squinty. The effort was certainly worth it - the cartridge is aligned as best as I can see. The sound has certainly improved - the clarity is enhanced. I can also hear the supporting instruments to a certain extent. The vocals and lead instruments still command center stage...their clarity is awesome to the point of being in a live performance. I am going to test run the cartridge for another 20 odd hours and will continue to revisit all those artifacts I thought I heard better in my MC setup. My focus will be on those support instruments - usually the bass guitar, violins and small percussion instruments. And for whatever reasons, in my past 10+ hours of listening to 2M Black...I have not heard it going out of control...as in a jarring or shrill note....so that is certainly a new level of nice for me. Cheers Shashi
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Posted By: pcourtney
Date Posted: 22 Nov 2017 at 12:51am
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Shashi - I have been using 2M Black with Accession for over 14 months, with various arms on my Pink Triangle PT1, you just need to give it more time my friend, when I got to about 100 hours of Accession and 2M Black - it was really magical in every sense of the word I have friends with £10,000 or more spent on their vinyl replay systems - and are very envious of my little Accession amp - fortunately for me I have not felt the need to go MC in over 35 years, but I was spoilt back in the mid seventies when my dad bought his Beogram 4000 - that was the benchmark for me, he still has it, and it sounds incredible, nearly as good as my Beogram 8002 with MMC1 cart
------------- GS Accession MM Pre, Red Wine Audio Signature 30.2 Amp and AKG K-1000 headphones |
Posted By: Fatmangolf
Date Posted: 22 Nov 2017 at 8:22pm
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One recent borrower of the loan unit said "Now I see what you were talking about. My OM30 and TD 160 sound like a new system. I am hearing good things I didn't know were on my records." He has ordered his own Accession now so I should get my Genera and the loan Accession back soon! ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: pcourtney
Date Posted: 22 Nov 2017 at 8:35pm
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I do hope you get it back soon Jon, and with the OM30 at the sharp end you have a great MM when I first bought my PT1 back in 1981 it came with an Ortofon 30E, and sounded incredible, I have a few SME 30E's now as back ups, what a combination with the SME III arm, no wonder I preferred it to the L*nn Sondek stuff of the time  ------------- GS Accession MM Pre, Red Wine Audio Signature 30.2 Amp and AKG K-1000 headphones |
Posted By: Fatmangolf
Date Posted: 22 Nov 2017 at 9:58pm
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Couldn't agree more and that's a very good photo Peter. It's a close colleague's Thorens deck and came second hand with a SME Series II Improved which sounded very good with the OM5 I aligned for him. Which would leave me jealous of the OM30 stylus he since fitted  if I didn't know how much he was enjoying it! It was stripping, cleaning, and refitting that SII Improved that persuaded me to start looking for a sensibly priced second hand series IV or V... that's another story with a happy ending told elsewhere - see my extensive GyroDec/Gorbe metamorphesis blog. Busy at work and squeezing other stuff in so I still haven't taken the Goldring 1042 MM off my Series IV tonearm and have played some more LP's tonight. As I wrote previously it doesn't do everything the Phoenix (over £2k new, mine was 2nd hand) MC does but I am enjoying listening to it just the same. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: shashirao
Date Posted: 22 Nov 2017 at 10:24pm
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So...the 2M Black is working perfect - playing better by the minute. The MM sound is loud(er than MC) and 2M Black is quite detailed. I am still in the gray zone (as in mind not made up yet) on those extras I have come to enjoy with my MC carts. Within the MC range - I own the Ortofon OM series, Cadenza Black Mono, Miyajima Zero, Miyajima, Kansui, Palo Santos Presentation and one of the Audio Technica cartridges. Suffice to say I have experienced the spectrum of improvement within the MC world. The Miyajima Kansui follows a different path (ring design) to overcome some of the issues Peter Ledermann mentions in his video. So now with the new thread with Ledermann's videos, I am intrigued. As per his recommendation and chosen path, the Moving Iron (fixed coil design) or Strain Gauge is the way to go to avoid the inherent flaws in MC design that lead to interference, noise and energy interfering with audible sound. And I am awaiting delivery of my ClearAudio Charisma. Which should put to rest any doubts or hopes of the best vinyl sound...especially from the MM world. My question is this....is there an end to a journey? Is it possible that Ledermann is proposing his own path because he believes in it...he hears that difference. But that would mean investing in a completely different design - the Fixed Coil design. Is the effort worth it? Will I magically hear that extra layer of chorals that were hiding in the recording room closet? I have a feeling that I have reached a point where the return on investment may not justify the investment/cost. Sure I may end up hearing a totally different style. Which I did when I switched from Ortofon OM 40 to Palo Santos Presentation to Miyajuma Kansui/Zero to now OM Black. There is hardly any cartridge that I would say plays really horrible. Like my single malts, each has its own attributes that I can perhaps put some words to....like notes of oak, leather, spice, lavendar with a hint of additional black sound, expanded soundstage and clarity in mid-range sounds. In my opinion what has really made the difference is the pre-amp. The cartridge offers me different flavors. But the pre-amp maturing has helped stabilize the sound and provide a baseline where there is clarity, depth and amazing details. My journey has been from the P******t Tube pre-amp...which I upgraded to use different tubes (Jolida). Then I switched over to the Revelation MC and finally to the Accession. This is where I have received and achieved the biggest bang for my buck. If I revisit my Ortofon OM series, I am sure with the Accession, I would have a much better experience and would not value an upgrade to say the OM Black as much. I mean as long as it plays the music I like in the manner it is supposed to be. Beyond that...unless the chorals bursts out of that closet and scream 'surprise!!'. Hence I am reluctant to even take a peek at the fixed coil world of cartridges. They may have certain bells and whistles that I am not hearing. But right now...I am hearing a perfect playback of the music I love and am hard-pressed to imagine there is any sound left out. Peter Ledermann's video is great and nice...but to me it falls short of offering any specifics on the how-to's - when it comes to azimuth, VTA, tracking or other topics. He recommends to listen, eye ball and go with the feel. I prefer tutorials on actual use of tools - like on using the Mint LP tractor or the digital scale. I do understand he cannot cover specifics for specific turntables...but I am looking for specifics. The overall video on cartridge design....I loved the video for the theoretical. But the cynical side of me also finds that as the Fixed Coil is better than Moving Coil promo.....and by the way...we make Fixed coil sales pitch. And they start at $7.5K and go very well with VPI turntables. So for now...I think I understand the design differences between MC, MM and MI thanks to all the detailed discussion on this forum. I also know that my 2M Black and Charisma will have enough in store to keep myself busy for another year. So my path of improvement will be amplification (Proprius with good speakers)...and if the Accession MC becomes a reality, I queue up to try it with my MC cartridges. And yes...its my day off (Thanksgiving holiday) and thus my ramble :) Cheers and happy holidays Shashi
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Posted By: Graham Slee
Date Posted: 23 Nov 2017 at 1:29am
I will try my best ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: ServerBaboon
Date Posted: 23 Nov 2017 at 9:11am
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I found the 2M black very sensitive to setup, especially VTA in my system. The more time tuning this the better. ------------- Steve ------------- Various bits of GSP Kit ..well two so far, unless you count the cables that is. |
Posted By: shashirao
Date Posted: 24 Nov 2017 at 6:32pm
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And I won't be completely surprised! :) :) But seriously...with the Palo Santos Presentation, I have been able to extract sounds that I had never heard before. The Accession is able to present the sounds with audible clarity. The good of the Presentation-Accession combination have been the ability to listen to a cough, ambient sound that slipped past the music recording process. The bad is...the Presentation really brings forth the image of a needle tracking thru a groove...one can hear the journey of the needle gliding thru the groove...even bringing forth the pre-echo of music in the next groove...as if permeating across the groove walls. With the Accession...these noise are limited to the empty sound bands before/after song tracks. Once the music begins...it is like all quiet in the recording room, the maestro taps his conducting stick and everyone's pouring out passionate music.
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Posted By: Richardl60
Date Posted: 26 Nov 2017 at 10:58am
| TNT audio on line comes up with some interesting comments re the value of a really good phono stage. Whilst the one in question is a silver wired value design (horror!) it is MM only BUT the review makes the point on a top phono stage cheap MM vs expensive cart and mediocre phono stage. The EGV gets a positive mention too! |
Posted By: Fatmangolf
Date Posted: 26 Nov 2017 at 11:46am
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Yes that "warts 'n' all" problem comes with better gear, Aside from only having perfect records I've found I can tolerate quite a lot of sounds like the groove noise, bumps, and pre-echo you've mentioned Shashirao. Some will disappear as the cartridge breaks in or your listening adapts to the extra musical detail and surface artifacts. I'm back on MC with my second hand Phoenix feeding the Elevator EXP with extra loading. I am sure the Ortofon 2M Black is a better cartridge than my Goldring 1042, maybe I will try one of the new top end MM's before long as I see Richard's point about the cart/preamp. FWIW I used to say the same thing about guitars and amps. ------------- Jon Open mind and ears whilst owning GSP Genera, Accession M, Accession MC, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC. |
Posted By: Richardl60
Date Posted: 03 Dec 2017 at 8:57pm
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I have been in touch will Jeff SPall at Audiomods - he forwarded an attachment with the schematics of his arm. To the uneducated the arm tube appears 'earthed', I wonder if this does comply with Graham's logic after all (albeit with some holes!). Graham do you have an email I can forward this to? Thanks |
Posted By: BackinBlack
Date Posted: 03 Dec 2017 at 9:10pm
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Richard, Graham's email address is at the bottom of this page, or you could attach the document to a PM to Graham. Ian ------------- Just listen, if it sounds good to you, enjoy it. |
Posted By: Graham Slee
Date Posted: 04 Dec 2017 at 11:48am
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Thank you Richard, attachment received. However, although they're all earthed they are not screened/shielded along their length. The arm tube would be connected to the cartridge "-" pins at the input end and then to the cable screen/shield at the mounting base end. And then, as demonstrated, the interference is reduced. ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 04 Dec 2017 at 2:09pm
| Thanks Graham. Ignoring to the holes in the tube for the time being if the cartridge was connected at the headshell rather than through the tags the arm is actually enabled to achieve the task set out some weeks ago? |
Posted By: Richardl60
Date Posted: 04 Dec 2017 at 2:14pm
| Or I could see if Jeff would construct with. Screened internal wiring and earth the screen at the outlet end of the arm? Which is likely to provide the best option (given the holes in the arm tube)? |
Posted By: Drewan77
Date Posted: 04 Dec 2017 at 6:39pm
From reading Grahams' posts on the subject, a moving magnet cartridge in an Audiomods arm seems less likely to be affected by HF & thankfully that is all I use... not that I claim any prior knowledge or technical reasoning for doing so! ------------- Older than I once was, younger than I'll be ............................. Andrew |
Posted By: Richardl60
Date Posted: 04 Dec 2017 at 6:49pm
| MC here! |
Posted By: Graham Slee
Date Posted: 05 Dec 2017 at 8:43am
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As manufacturers distance themselves further and further away from physics it becomes impossible to make any technological progress in analogue audio electronics. Perhaps one day the stubbornness will subside, and reality will dawn on those who currently would rather offer eye candy than beneficial solutions? ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 05 Dec 2017 at 10:12am
| Not sure whether this is aimed at Jeff, me or MC manufacturers? |
Posted By: Graham Slee
Date Posted: 05 Dec 2017 at 4:41pm
Turntable and arm manufacturers... sorry to say.  ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |
Posted By: Richardl60
Date Posted: 12 Dec 2017 at 11:28am
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Graham i5 looks like I will be ordering an Audiomods from Jeff but will be asking him If he can use screened arm cable in the tube (don’t ask don’t get) Woud I be right in thinking any screening needs earthing at the arm base earth - I am opting for a separate rather than continuous loom. Kind regards Richard |
Posted By: Graham Slee
Date Posted: 12 Dec 2017 at 3:45pm
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The screen should carry the '-' signals: cartridge to arm output; arm output to phono stage. As the arm is (still) not part of the screen, it should be 'earthed' as normal (the little black wire). ------------- That none should be able to buy or sell without a smartphone and the knowledge in how to use apps |