VSPS Help/Suggestions - 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 31st October 2005, 07:31 AM   #1
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Default VSPS Help/Suggestions

Hi,

I built a VSPS phono stage, and it sounds kind of terrible. I am wondering if anyone can help me figure out what the problem is. The problem with the sound is that the treble is rolled off, and everyting sounds a bit recessed. The lower-mids are a syrupy (which is okay) , the bass is full, but the treble is really just not there.

My build is as follows:

There is a pair of LM317 circuits (schottkey rectifiers, 2200uF smoothing caps, 2 10uF caps after the output, etc.) that provide +/- 15V. From that there are dual mono pairs of 12V regulators (LM340/LM7912) that use the suggested 220uF caps (FMs) on the in and out pins. The curcuit itself uses dual mono opa627 opamps. The feedback resistors are all Riken Ohm, the feedback caps are silver mica, the rest of the resistors are metal film, the output caps are Solens, and there are .1uF film and foil caps on the voltage pins of the opamps.

So, what I am trying to figure out is whether it is the circuit, the PS, or a problem with my turntable (which has been in storage for about 6 months) Any suggestions on what to try? The two things that seem like early candidates are the silver mica caps and the PS bypass caps, but I am not sure.

I attached a blurry photo that should give some idea of the setup.
Attached Images
File Type: jpg vsps.jpg (36.2 KB, 275 views)
  Reply With Quote
Old 31st October 2005, 08:46 AM   #2
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
well, I guess I not only spoke too soon, but I waited too long to edit. Everything seems to be okay now, and it was just an issue of everything burning in.

So as to not have created a wasted thread, has anyone tried putting a buf634 within the feedback loop of the vsps to boost current a bit?
  Reply With Quote
Old 31st October 2005, 12:30 PM   #3
diyAudio Moderator Emeritus
 
Bas Horneman's Avatar
 
Join Date: Apr 2002
Location: The Netherlands
Blog Entries: 18
Good to hear all is well!
  Reply With Quote
Old 31st October 2005, 01:23 PM   #4
rjm is offline rjm  Japan
Richard Murdey
diyAudio Member
 
rjm's Avatar
 
Join Date: May 2004
Location: Kyoto
Blog Entries: 103
Hi,

I'd nonetheless double-check that the resistors and capacitors in the feedback loop are the correct value and correctly connected.

Your build appears neat and tidy and well thought out. I wouldn't have separated the regulator and VSPS circuits on separate boards, and I 'm not so sure using Solens for power supply decoupling is the best solution, but these are likely minor points.

/R
  Reply With Quote
Old 31st October 2005, 05:58 PM   #5
diyAudio Member
 
dsavitsk's Avatar
 
Join Date: Jan 2005
Location: Hartford
Quote:
Originally posted by Bas Horneman
Good to hear all is well!
Thanks. For whatever reason, I had decided to not believe in burn-in in this case and just assumed it would work immediatly. I think it is by far the most dramatic example I have heard, however. Part of it is likely that the cartridge (a clearaudio) on the table needed to get going after a long time with no use.

Quote:
Originally posted by rjm
I'd nonetheless double-check that the resistors and capacitors in the feedback loop are the correct value and correctly connected.
Everything seems to be working quite well now. I am pleasantly surprised by how good this thing sounds.

Quote:
Originally posted by rjm
Your build appears neat and tidy and well thought out. I wouldn't have separated the regulator and VSPS circuits on separate boards, and I 'm not so sure using Solens for power supply decoupling is the best solution, but these are likely minor points.
The seperation is why I added the extra PS bypass caps.

As for Solens, they are the output caps. (The power decoupling caps are dayton film and foil.) I agree that more boutique-y caps sound a bit better, but at their price point, I think these things can't be beat. While they get a lot of bad press around here because they are so cheap, my sense is that all of their sins are ones of omission. They may not ofer the absolute last level of resolution, but they are pretty darn close for the money.

Also, I would actually think that with just an opamp in the circuit here, that one should be able to get away without the caps at all. I'll take some measurements later and see if this is the case.

-d
  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
Pics of my VSPS davidfmartin Analogue Source 0 29th March 2009 03:05 AM
VSPS and Phonoclone boards heady Swap Meet 7 30th October 2007 08:18 AM
Thanks, RJM! Just built a VSPS nobody special Analogue Source 2 1st August 2005 08:48 PM


New To Site? Need Help?

All times are GMT. The time now is 04:04 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