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MM or MC ?

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Graham Slee View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep 2017 at 10:22am
Most will know my feelings regarding moving coil. A few technically minded might just have noticed the difficulties it leads to - they only need to take a look at some of the earlier designs by reputable designers (there aren't many) to realise. Few of those designs work in today's "connected world" without hearing 'disturbances'. Electronic components exist to service the requirements of today (which manufacturer is going to run an expensive production line making components few will buy?), and the result of that is there are precious few suitable components available to do the job. I read elsewhere on this forum about a kit head-amp for MC with which the member was very happy. The FET used is no longer manufactured and neither are all the alternatives, so that's a dead-end. The British or Dutch made BC109C transistor which could have helped can now only be found in museums. Even so, these old circuits have something in common to the guitarist's fuzz box - they do not consider the slew-rate of the signal emanating from a MC cartridge. The math is simple and has existed numerous years so what's the excuse? It's no use me going and asking others for their help. Therefore I have to conjure up a circuit (or three) in an attempt to make the listener's lot a happy one, using components that are not designed for the job, because no component ever was (apart from a SUT of course).
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Aussie Mick View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Aussie Mick Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep 2017 at 12:07pm
Hi Graham,
    Yes, I've read through your (thoroughly technical and beautifully explained) ideas on the failings of MC. I'm very lucky in that where I live is mercifully quiet electronically, and in having a dedicated listening space in a studio that is not connected to the main house. I've enjoyed my 2M Black for few years now, but even on ten hours of experience, I know I'm going to enjoy the Apheta 2 even more.
The "problem" as I see it, Graham, is that you appear to have overcome the inherent weaknesses of which you speak when it comes to MC. Does that sound right? You identified problems, did your research and found solutions. Then you proceeded to find consistent and reliable ways to manufacture your product.
That sounds like good engineering practise to me! I'm loving the EXP/Reflex combination, Graham. Loving it.
Mick.
Rega RP8/Ortofon 2M Black/Rega Apheta 2 - Reflex M/Elevator EXP - C.E.C. TL5 CD Transport - MacBook Pro/Roon - Majestic DAC - Proprius - PMC Twenty5.22
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fatmangolf Quote  Post ReplyReply Direct Link To This Post Posted: 10 Sep 2017 at 4:11pm
Seconding Mick's praise for GSP MC stages the Elevator EXP has made the difference between the three MC's I tried very clear but made them all excel with the music I played. I started with a second hand DL-103 then made it 'naked' but carefully removing the plastic box, the EXP made the difference in clarity obvious. When I bought a Zyx R100-L the EXP was there to reveal the extra detail, and after a couple of years of heavy use I got a second hand Transfiguration Phoenix and the EXP showed why that cartridge is highly regarded.

Occasionally I have heard interference coming through but it is an external problem and not a factor in my listening. Again I think the EXP's design helps with this. Thank you very much Graham for the years of work that went into developing the Elevator EXP and your honest account of the problems in amplifying the signal from an MC cartridge.

Jon

Open mind and ears, whilst owning GSP Genera, Accession, Elevator EXP, Solo ULDE, Proprius amps, Cusat50 cables, Lautus digital cable, Spatia cables and links, and a Majestic DAC.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Alasdair Quote  Post ReplyReply Direct Link To This Post Posted: 08 Jun 2018 at 10:52pm
Oh dear ... I've just made a journey in the other direction!
Many years ago I got a Denon DL103, worked out how to make it sing and thought this was all I would ever need. I then fitted it with a metal body, got Expert Stylus to fit it with a Paratrace stylus and sapphire cantilever, worked out how to make that sing and thought it was even better and even more definitely all I would ever need. I had it in a Mayware Formula V arm set to maximum mass, running through a 'BlackHead 2' step up transformer into a Genera phono preamp. 
Then came the time when the Denon needed another retip and before sending it away I had a rummage in my old cartridge box. First to come out was an old Rega RB100 fixed stylus moving magnet, which had astonishing stereo imaging, clearly beating even the Denon, and was a treat on some orchestral pieces but ultimately was limited by its non-flat frequency response. Then out came an old Goldring G900SE which I had retipped with a 0.5 though naked conical stylus by Expert Stylus as an experiment many moons ago. Help ... this was seriously good but then its ancient stylus suspension collapsed. Mantra Audio came to the rescue with a Tonar hyperelliptical stylus which tracks perfectly at 1.2g. It's very sensitive to input capacitance (I found 150pF in the Genera plus about 70pF tonearm leads was right) but once I had it working right the stereo image, the projection of vocals, the bass, the toe-tapping were all excellent and, well, the Denon DL103 is in the 'old cartridges' box and the step up transformer is now sitting on the shelf. 
Points to Graham, methinks ...
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Graham Slee View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 12 Aug 2018 at 12:51pm
I feel this topic has been left somewhat open ended given my findings with the Accession MC phono stage and PSU1 Enigma power supply.

It should be common sense to understand that small signals are harder to work with than large signals.

When you have a situation, like with MC, where -60dB at 100Hz is 73.1dB less than its rated 1kHz output (helped by record EQ), so with a 0.2mV output cartridge you are expecting a 0.000044mV signal to survive (after all reviewers believe they can hear such low level stuff).

It isn't much better with an average output MM: here for a 3.5mV output MM it is 0.00077mV, nearly 20 times easier.

In an ideal world the only noise you would have is that of resistors and amplifier (chip or discrete) input-noise x gain, but such thinking omits all the unthought-of of "crap" which affects everything in many different ways.

With a bandwidth of 100Hz and amplifier input noise of 5nV/root Hz we have 50nV of noise which is 0.00005mV. At -60dB the MM is more than 10 times above this - the MC just below, so the reviewer must be telling fibs.

OK, you can get op-amps with a little less noise, but resistors contribute their own too, so the tiniest MC signal is always going to be compromised - the MM less compromised.

All we can do is "work" on the MC stage in other ways to help it on its way.

One way we can do this is to iron out noise or distortion in the power supply ground. Signal is referenced to ground, and if ground can "move" then signal "moves" because of it, and it shouldn't, but this is part of the unthought-of "crap".

The PSU1 Enigma helps sort out some of this. It does not improve on the already correct grounding method within the PSU1, but it recognises that the usual thinking about reservoir capacitors is wrong!

A capacitor's capacitance changes plotted against frequency. We should try and make that flat, but the physics makes it impossible. In AC theory the supply and ground are one and the same. But if the capacitance changes with frequency it cannot be one and the same.

All we can do is make it flatter by recognising which capacitors can do this. And that is what I did.

It helps dig smaller MC signals out of the noise which intermodulates it. It might not work with the -60dB signals the reviewers imagine, but with what I call normal music, it "damages" it less.

It brings both ideas closer together in how they sound, or as I perceive they sound, which some of you have also heard.

It isn't the case of me changing my mind over all the technical things I have written. It is not a case of me now saying MC is better than MM. It is basically me saying that I can now enjoy music using MC as much as I can using MM.

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Ash View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ash Quote  Post ReplyReply Direct Link To This Post Posted: 13 Aug 2018 at 10:45pm
So if the key moment for you with MC was the realization that it was the reservoir capacitors in the PSU1 that needed attention, why not try the Enigma PSU1 with the Accession MM? Is there improvement to be had with moving magnet too?
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Graham Slee View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Graham Slee Quote  Post ReplyReply Direct Link To This Post Posted: 14 Aug 2018 at 3:18am
Originally posted by Ash Ash wrote:

So if the key moment for you with MC was the realization that it was the reservoir capacitors in the PSU1 that needed attention, why not try the Enigma PSU1 with the Accession MM? Is there improvement to be had with moving magnet too?


I understand what you're getting at but it doesn't seem to be so. Perhaps somebody with trained ears could hear some improvement? Mine are musically untrained.
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