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capacitance loading logic

Printed From: Graham Slee Hifi System Components
Category: Music
Forum Name: Music!
Forum Description: Because it's #AllAboutTheMusic
URL: https://www.hifisystemcomponents.com/forum/forum_posts.asp?TID=5314
Printed Date: 06 Dec 2021 at 4:55am
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: capacitance loading logic
Posted By: Teesside Tom
Subject: capacitance loading logic
Date Posted: 13 Oct 2021 at 9:43am
Good Morning, last week I took delivery of an Accession M phono stage and Enigma ps on home demo. Under the heading Cap Load the Accession booklet states the cartridge sees the capacitance of the tonearm wiring and arm cable plus whatever is set on the phono stage via the dip switches, the capacitance value of the arm wiring and interconnect should be subtracted from the cartridge capacitance which will leave a value to be set on the dip switches for best matching.

Yesterday I received an email from my turntable / tonearm manufacturer stating that the combined capacitance value of the tonearm wiring and cable, which are both Litz silver cores is 320pF.
The cartridge is an Audio Note IQ3 mm, recommended load capacitance 150 - 200pF.

This would leave a negative value and so to my logic the dip switches should all be set to zero or out?
This is the nearest match I can hope for unless I change the cartridge or wiring, is my logic correct?

I took delivery of the turntable in late March, ordered last December, when ordering I already owned and was using the cartridge and I cannot help but feel the dealer has done me something of a disservice by not flagging up that by specifying the top option of the Litz wiring/ cabling I was creating a mis match from the point of capacitance matching. 
This is my first experience of a stand alone adjustable phono stage previous units have been integrated in the pre amp (which Iv'e had for at least 15 years) it 's a bit of a learning curve in more than one way.



Replies:
Posted By: Teesside Tom
Date Posted: 13 Oct 2021 at 11:34am
My apologies for posting in my haste under the topic of Music, it should have been under Graham Slee phono stages.Confused


Posted By: patientot
Date Posted: 13 Oct 2021 at 3:59pm
Zero is probably the best option you can hope for here under the circumstances. Unfortunately many tonearm manufacturers automatically assume the end user is going to use a moving coil cartridge (not really affected by capacitance) so they will use higher capacitance wiring in the tonearm and not tell you.

Bear in mind that as we age we lose our high frequency hearing ability so you may not notice that much difference in a 320pf load vs. a 200pf total load on this cartridge. It just depends on those factors, which are going to be different for the individual.

When you set the Accession switches to 0pf, how does it sound to you on records you are familiar with?


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Reflex M + PSU-1 used with AT VM95ML, Stanton 680mkII + Ogura, and Shure M35X cartridges.


Posted By: Graham Slee
Date Posted: 13 Oct 2021 at 4:00pm
Originally posted by Teesside Tom Teesside Tom wrote:

Yesterday I received an email from my turntable / tonearm manufacturer stating that the combined capacitance value of the tonearm wiring and cable, which are both Litz silver cores is 320pF.
The cartridge is an Audio Note IQ3 mm, recommended load capacitance 150 - 200pF.

Now, what kind of wazzock who understands how these things work, would do a trick like that? Answer: a wazzock who doesn't understand how it works. Hopefully it's not one of my dealers.

Here's what a Technics SL1200 II arm and cable measures (excuse the dust).

tonearm and cable capacitance left

tonearm and cable capacitance right

(PS. It's OK by me to post in the wrong place Wink)



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Not simple enough for Google-Bot to understand...


Posted By: lfc jon
Date Posted: 13 Oct 2021 at 6:53pm
I know some people don't like RS, But when I got back into Vinyl one of the first things they asked me was did my amp have a phono amp built in and whether it was MM or MC as I had a set budget. They said to me you would be surprised how many people come back and complain that their turntable didn't work with their amp and had not put money a side for a phono amp, so being that it sounds like you were spending a lot of money on your turntable I would have thought they would have asked some questions or given you some idea of what you were getting your self into.
But at lest your on the right forum to get good answers from vary good people


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Pro-j tt,Ortofon 2m Bronze cart,Audiolab 8300CD,GS Reflex M. Solo headphone amp both with PSU1,MF M2si amp, Monitor audio silver 100 speakers, Atlas speaker cables and GS interconnect cables


Posted By: ICL1P
Date Posted: 13 Oct 2021 at 9:20pm
I’m guessing the arm is an Audio Note Arm Three.  https://www.audionote.co.uk/arm-three - https://www.audionote.co.uk/arm-three

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Ifor
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Reflex M & ACCESSION M, CuSat50, Majestic DAC, a Proprius pair.


Posted By: Fatmangolf
Date Posted: 13 Oct 2021 at 11:36pm
A little disappointing with the cartridge and arm from same manufacturer but it may sound better than the specs suggest. And your Accession can help to counter any brightness as the US setting cuts over 2dB at 10 kHz compared to standard RIAA.

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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: Teesside Tom
Date Posted: 14 Oct 2021 at 12:16pm
Thank you all for your comments and suggestions, the tonearm is Audio Note and was bought new with a new TT 3 and PSU 3 power supply, as the IQ3 cartridge was maybe 6 months old it made no sense to me practically and financially to change everything at once, my old turntable had no ps so I was expecting a fair step up anyway. The Audio Note dealer actually talked up the mm cartridge and suggested I may well stay with it as I had mentioned I would probably be going to an mc cartridge at some point. 
Before receiving the Accession M I drew up a list of albums and tracks to play and one of the first was U2's Joshua Tree, I had set the capacitance to 100pF, and it was soon obvious the Accession was an appreciable step up from my on board phono stage, likewise Bonnie Raitt's album Nick of Time.

Trying to listen objectively is not easy especially when playing "favourite" albums and also I find that when listening to the Accession on certain tracks as I did last night you have to decide if the "more" you are hearing is the Accession exposing an issue on the recording or if you like is it the gap I have in the matching of the capacitance. System warmed up, all capacitance switches up / zero, I put on The Simon and Garfunkel Collection, an original in top nick, most tracks sound ok but knowing what I know now I'm thinking could it be better. On B O T Water there is a point where Art G is starting to reach to get the higher notes and the violins come in and there is a high crescendo finish which sounds somewhat strained - (S&G liked to multi track layer - yes)  recording or capacitance mis match? 

I think my route could well be Accession C with Enigma and an mc cartridge checking first that the mc can be optimally matched with the Accession C. Changing wiring / cables is too horrible to contemplate.


Posted By: Graham Slee
Date Posted: 14 Oct 2021 at 12:28pm
Here's the electrical plot of peaking due to cap load on the 1042. Ignore the massive qty of dBs, it's only relative, but it illustrates the peak is +2dB at 420pF, +1dB at 320pF, and flat at 200pF. The frequency at the peaks is around 8kHz and will be cymbals and vocal esses (mostly female) - in other words, bright.

The electrical plot cannot illustrate the mechanical tuning (think tuning fork), which helps extend the frequency response to 20kHz - here it's -3dB at 16kHz 200pF loaded.

1042 simulated peaking

(please excuse the curved vertical)


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Not simple enough for Google-Bot to understand...


Posted By: BackinBlack
Date Posted: 14 Oct 2021 at 3:17pm
I find it rather disappointing that the dealer, knowing an IQ3 cartridge was to be used, recommended the Arm combination whose cable has in the published specification a total capacitance of 320pF, whilst the same manufacturers specification for their IQ3 cartridge clearly states that the combined capacitance of the arm, interconnect and amplifier should be no more than 200pF.
Albeit somewhat late to this thread, having been led down the "(more expensive) silver is better" path, I have found in my own system with MM, silver arm wiring/interconnect to give a rather bright and harsh sound. I much prefer a good copper litz for Arm wiring, with CuSat interconnect.

Ian


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Just listen, if it sounds good to you, enjoy it.


Posted By: Teesside Tom
Date Posted: 14 Oct 2021 at 5:01pm
Can I clear something up, it was my choice to go with the Litz silver wiring even though I had read in component reviews for example how the reviewer had changed cables, copper to silver for example and thought it preferable but also noted some might prefer the copper and suggested trying both at home if possible. The problem is with tonearm wiring and arm interconnect cable of course it's not that straight forward. My downfall if you like was being aware of different opinions on copper and silver but knew nothing of capacitance and matching
The dealer is not one for lab test results and such, more a listen and go with your hearing person and it is possible he was not aware of the high capacitance of the wiring, but although I think he should have been I had to go to Audio Note for those figures. 
At least 12 years ago I bought a Clearer Audio mains cable, I think they are 6 nines copper, silver coated, pleased with it, I now have two of their mains distribution blocks and 4 of their mains cables so I had no thoughts of there bing an issue specifying the Litz wiring although this is silver only.

It's a funny old world, my previous turntable was a Nottingham Analogue Spacedeck which I had for many years and I was looking at going to another N A turntable, the Dias with Martin Bastin power supply. I telephoned  a long time Nottingham Analogue dealer on the morning I went to the Audio Note dealer and said I was interested in the Dias, to my astonishment he said well we don't do much of that make now, and I pointed out there was a 2/3 month wait as their order books were full. His reply was they were nearly all overseas orders and tried to interest me in other makes and one in particular they had. 
I think this and the months I had spent looking had taken it's effect and I had virtually decided to place
an order when I entered the A N dealers demo room. It'l all get sorted, if your system is sometimes not up to snuff I can recommend Ardbeg single malt, Australian Shiraz or Merlot red from the Barossa region or a white Sauvignon (N Z) from the Marlborough Estate - don't mix the grape with the grain!


Posted By: patientot
Date Posted: 14 Oct 2021 at 5:19pm
Originally posted by Teesside Tom Teesside Tom wrote:

On B O T Water there is a point where Art G is starting to reach to get the higher notes and the violins come in and there is a high crescendo finish which sounds somewhat strained - (S&G liked to multi track layer - yes)  recording or capacitance mis match? 



Part of that is likely due to the recording itself. I'm not the biggest S&G fan but if you listen to their recordings, even later CD versions, you can hear vocal sibilance captured by the microphones, instruments occasionally overloading the mic, etc. This is quite common on a large number of 60s rock and pop recordings if you listen very, very closely.

Additional capacitance can exaggerate that somewhat. The only way to know for sure if it bothers you would be to make a digital recording of different settings via the Accession outputs and A/B them. That or you could measure the cartridge frequency response using an accurate test record and software. As Graham said, the actual frequency response will be a little different than the electrically modeled response.

Re: the Accession MC, if you look at the specs and info on this site, it will say what cartridge output range is recommended and what loading options are available. Compare that with some cartridge specs.

If you want to get some rough ideas of how things sound with the Acc. MC and different MC carts, you can look at Bob Wood's videos:

https://www.youtube.com/c/BobWoodMusicAndVinyl/videos - https://www.youtube.com/c/BobWoodMusicAndVinyl/videos


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Reflex M + PSU-1 used with AT VM95ML, Stanton 680mkII + Ogura, and Shure M35X cartridges.


Posted By: Teesside Tom
Date Posted: 25 Oct 2021 at 8:02pm
Thanks patientot for the very useful comment on mc cartridges not really being affected by capacitance, sorry for the late reply.


Posted By: Fatmangolf
Date Posted: 25 Oct 2021 at 9:34pm
The load capacitance must be much larger because the MC self-inductance is lower.



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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.



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