Cartridge capacitance load? I have some questions! - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 20th July 2005, 10:17 PM   #1
Kuja is offline Kuja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2005
Location: Belgrade, Yugoslavia
Default Cartridge capacitance load? I have some questions!

Hi,

I recently got a Shure V15 VxMR.

You can read about my initial dissapointment with it here:

...and here:

Lots of folks on various forums suggested that the capacitance might be the culprit.

Shure recommends capacitance load of 250pF.

My phono preamp's (Graham Slee, GramAmp 2 SE) capacitance is 150 pF.

My SME 3009 S2/imp is rewired with 40 cm of Van den Hul MCS - 150 M cable.
http://www.vandenhul.com/cable/mcs-150m.htm
capacitance is not stated

Cable from tone arm to preamp is Van den Hul D - 502 HYBRID
http://www.vandenhul.com/cable/d-502-h.htm
capacitance is 75pF per 1 meter. I have 1.2 meters cable lenght, so it should be 90pF

Together with preamp's 150pF it makes it 240pF, leaving a reserve of 10pF for tone arm internal wiring, which is unknown but I guess it is higher than that.

Is going a little bit above 250pF, a huge, make or break difference? Can it be the cause of my problem with the Shure?

I could cut in half my Van den Hul, thus lowering it's capacitance - lot cheaper than losing money on selling my V15

But I wouldn't like to ruin a perfectly good cable, just to discover that nothing had changed...

What would happen if I intentionaly go significantly lower than recommended 250 pF (cutting the Van den Hul to only 30 - 40 cm)?

Would I get some aditional boost in the treble?

Some folks said maybe, but some suggested different:
http://www.audioasylum.com/audio/vin...es/432239.html

What do you think?

Thanks,

Aleksandar
  Reply With Quote
Old 21st July 2005, 12:39 AM   #2
Kuja is offline Kuja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2005
Location: Belgrade, Yugoslavia
I forgot something.

I'm embarassed to admit, but inside my turntable I tied a simple loose knot on a VdH D-502 cable going from tone arm base to my phono preamp.

I did it to prevent my four year old son from yanking it out and breaking something, since it is directly soldered to the pins on the arm's base.

I didn't hear any difference with my previous Ortofon MC1 turbo, but this might be due to MCs not being so fussy about cable capacitance (so I heard ).

Can this be the source of my problem (I could try utying it, but it's 2:36 AM here and I would wake up everybody by playing some loud music )?

Any thoughts?
  Reply With Quote
Old 22nd July 2005, 02:28 PM   #3
diyAudio Member
 
Join Date: Sep 2004
Location: virginia
Look at this thread.
moving coil loading

For the Shure V15V I suggest a maximum total capacity of 120 pF.
This gives a resonant Q of about 0.7.
Regards,
Ray
  Reply With Quote
Old 22nd July 2005, 04:02 PM   #4
Kuja is offline Kuja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2005
Location: Belgrade, Yugoslavia
Quote:
Look at this thread.
http://www.diyaudio.com/forums/show...&threadid=59375

For the Shure V15V I suggest a maximum total capacity of 120 pF.
This gives a resonant Q of about 0.7.
Regards,
Ray
Ray,

Thanks fr the link!

But, since I'm kind of a newbie (but I'm willing to learn ), I only got a mild brain tumor from reading this thread .
I have no background knowledge in electronics and I'm only begining to grasp the concepts.

Please bear with me - I would really like to know what are the sonic consequences of higher vs. lower capacitance in relation to 250pF that is recommended by Shure?

Does higher capacitance cause rolled off treble, something I'm experiencing right now?
Will much lower capacitance bring the treble back?

I can't go as low as 120pF, since my phono preamp is 150pF.

What do I do?

Make the cable between the arm and the preamp as short as possible and live with the fact that the things are not perfect and that the Q (whatever it is) will never be 0.7 ?

Thanks again,

Aleksandar
  Reply With Quote
Old 22nd July 2005, 05:36 PM   #5
diyAudio Member
 
Join Date: Sep 2004
Location: virginia
Aleksandar,
The cut off frequency is determined by the Q and the resonant frequency of the cartridge inductance and total shunt capacitance. The higher the capacity, the higher the Q and the lower the resonant frequency. This can cause the high frequency roll off to start at a lower frequency.

I had the same problem with my V15V. Shure recommended 250 pF terminating capacity so I bought a phono cable with an advertised 250 pF of capacity. The sound was terrible. My preamp had 100 pF capacitors shunting the preamp inputs to ground to prevent RFI as well as an elaborate switch network with lots of shielded wire. I estimated the preamp input capacity at about 200 pF. If you include the tonearm wiring the total capacity was probably about 500 pF. I fixed the problem by buying another preamp with an advertised input capacity of 20 pF and used very short lengths of low capacity phono cable for the connections.

Use as short a length of low capacity phono cable as possible.
Regards,
Ray
  Reply With Quote
Old 22nd July 2005, 05:50 PM   #6
Kuja is offline Kuja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2005
Location: Belgrade, Yugoslavia
Thanks!
  Reply With Quote
Old 22nd July 2005, 10:29 PM   #7
dnsey is offline dnsey  United Kingdom
diyAudio Member
 
Join Date: Mar 2004
Location: Shropshire, England
Before spending much money and time, try the effect of adding some capacitance.
It's counter-intuitive, but cartridges often behave strangely in this respect!
  Reply With Quote
Old 24th July 2005, 12:09 AM   #8
Kuja is offline Kuja  Yugoslavia
diyAudio Member
 
Join Date: Jun 2005
Location: Belgrade, Yugoslavia
I tried this:

Since my CyrusIII amp has a phono preamp on its own, I plugged the V15 in.

Cyrus' phono input is rated at 50pF, opposed to Gram Amp's 150pF.

With 100pF shaved off, I expected a huge difference.

Well, nothing spectacular happened. There was some difference, but I guess that it was only due to different preamps.

Real acoustic memory lasts only 15 seconds or so and I was fiddling for too long with the cables, ground lead, etc. to be able to do something approaching A/B comparison. But if some huge positive difference was present, I would notice it for sure !

Hmmm... should I go further, drasticaly shortening the IC, or I should try adding some capacitance instead?

How do I add capacitance?
  Reply With Quote
Old 24th July 2005, 02:18 AM   #9
diyAudio Member
 
audiobomber's Avatar
 
Join Date: Jul 2004
Location: Sudbury, Ontario Canada
Quote:
Originally posted by Kuja
Hmmm... should I go further, drasticaly shortening the IC, or I should try adding some capacitance instead?

How do I add capacitance?
You can add capacitance by soldering a small (picofarads) cap across the headshell leads or across the RCA's (+ to -) or into the phono stage. Or change the tonearm lead or phono stage to one with higher capacitance.

You are now very close to the manufacturer's spec. Some people may prefer some other value of capacitance, but how wrong could the Shure spec be? IMHO you're barking up the wrong tree. IOW, I don't think capacitance is your problem. Maybe you just don't like the sound of the V15, not everyone does. The Ortofon Turbo is a pretty lively cartridge. Some would say excessively bright. The Shure is on the other end of things sonically. Adding capacitance will make the sound duller, not more lively.

The most common cause for the symptoms you describe (lack of HF life?) is VTA, but you've already tried that, right? Nevertheless, I recommend you try leveling the cartridge and then move the pivot up *very* slightly up from level. I don't know what else it could be, but I think you're wasting your time with capacitance.

Good luck. Let us know what you come up with.
__________________
Dan
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Amp sim output load capacitance, how much? cbdb Solid State 9 4th June 2009 04:42 PM
Capacitance Meter Questions mtl777 Parts 5 26th December 2007 02:05 PM
cartridge load check woodturner-fran Analogue Source 14 31st March 2006 11:06 AM
Back Load Horn Questions serenechaos Full Range 2 12th March 2005 10:32 AM
Load capacitance specs for 16.9344 Mhz crystal? Ruach Parts 0 4th June 2003 02:30 AM


New To Site? Need Help?

All times are GMT. The time now is 11:47 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2