Noisy volume controls in old receivers - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 11th October 2002, 03:43 AM   #1
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default Noisy volume controls in old receivers

here I am plagued with noisy controls in the Pioneer SX838 which I purchased prechildren (now they are getting married! -- I carried this unit from Harvey Electronics to my office on 53rd Street on a hot summer day). I am wondering whom else out there hasn't given thought to the following solution to the noisy and failing volume controls in these great, power receivers -- something I have mentioned before. Use the existing control to drive the input to a serial ADC and use the ADC to drive a digital pot from ADI (www.analog.com). SMT, the real estate would be about 0.3 sq inch. Any comments?
  Reply With Quote
Old 11th October 2002, 03:56 AM   #2
cowanrg is offline cowanrg  United States
diyAudio Member
 
cowanrg's Avatar
 
Join Date: Apr 2002
Location: Lafayette, CO
Send a message via AIM to cowanrg
just clean the pot and it will be back to normal. very simple to fix. its just dirt and grime in the knob itself.
  Reply With Quote
Old 11th October 2002, 01:00 PM   #3
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
Default unfortunately

the pots in the pioneer are almost impossible to get to to clean -- I've done it.

I think that the "dirtiness" in some small measure is due to forced-air cooling and heating -- which blows around a lot of dust, even with an electrostatic cleaner on the furnace. Thus the problem recurs.
  Reply With Quote
Old 11th October 2002, 01:11 PM   #4
diyAudio Moderator Emeritus
 
roddyama's Avatar
 
Join Date: Jan 2002
Location: Michigan
Hi Jack,

The “dirtiness” is usually due to oxidation. I will periodically go on a pot turning binge (once every few month) to “wipe” the oxidation away. This is not to say the force air heating and cooling has nothing to do with it, it is certainly a contributor. Most of my equipment is more then 20 years old and is still working fine with this routine.

Rodd Yamas***a
  Reply With Quote
Old 11th October 2002, 03:28 PM   #5
diyAudio Member
 
MRehorst's Avatar
 
Join Date: May 2002
Noisy pots are often caused by DC getting to the pot via a leaky coupling capacitor. Check for electrolytic coupling caps and replace them with new ones. Film caps should be OK.

MR
  Reply With Quote
Old 12th October 2002, 02:45 PM   #6
G is offline G  United States
diyAudio Member
 
G's Avatar
 
Join Date: Apr 2002
Location: Belleville, IL.
Wouldn't it be easier to just replace the pots with some high quality plastic film pots? Why add more devices to the signal path?
__________________
Gavin
  Reply With Quote
Old 12th October 2002, 03:33 PM   #7
diyAudio Member
 
Neutron Bob's Avatar
 
Join Date: Jul 2002
Location: San Clemente, CA
Send a message via Yahoo to Neutron Bob
Default Noisy Wipers!

The best solution I have seen is called Stabilant 22A, if I remember correctly. You have a litttle oxidation on the wiper surface. I think it was sold under the name "Tweek" years ago.

I just looked the juice up for you: http://www.stabilant.com/bccomp.htm

I think this clears up the air regarding Sumiko's sale of the product years ago. It is used today (22A) in VW/Audi electrical systems. I can assure you, unless you are dealing with very low signal or RF applications, it's the best thing since the invention of pre-sliced bread!

Use the genuine article. You'd be amazed at how well it works in potentiometers. If you are into camera repair, especially "heavy brass" vintage cameras (with analog computers for exposure control), the technicians swear by it.

Bobby
  Reply With Quote
Old 12th October 2002, 08:24 PM   #8
diyAudio Member
 
MRehorst's Avatar
 
Join Date: May 2002
Quote:
Originally posted by G
Wouldn't it be easier to just replace the pots with some high quality plastic film pots? Why add more devices to the signal path?
You misunderstood. I suggested replacing a defective capacitor that is already there (assuming it is there). IF the problem is DC on the pot due to a leaky coupling cap, replacing the pot will not solve the problem.

MR
  Reply With Quote
Old 13th October 2002, 03:50 AM   #9
diyAudio Moderator Emeritus
 
roddyama's Avatar
 
Join Date: Jan 2002
Location: Michigan
Hi Bobby, Jack,

Here’s what we had in the early 80’s. The stuff is called Cramolin. It was marketed by monster cable and then went to Craig Industries. It appears to be a German company as can be seen by its home page; yeah, the stuff is still around. I think in spray form.
http://www.cramolin.de/

Rumor has it that Craig was sited by the USEPA for the propellant they were using in the spray cans and blamed it on the anti-oxidant ingredients. This allowed them to change the formula and market it under the same name (reported to be less effective and probably cheaper).

I did use the stuff on my connectors, but it difficult to get at the Alps type sealed pots. It will go through my connectors again once I figure I have the system where I want it, and I know it will stay that way for a while.

Here’s a photo of the stuff.

Rodd Yamas***a
Attached Images
File Type: jpg cramolin_01.jpg (66.0 KB, 119 views)
  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
Has Anyone Tried The P&S Volume Controls? dantwomey Chip Amps 5 22nd January 2010 08:57 PM
Blending Guitar Volume Controls Hyounce Parts 0 9th April 2006 06:45 PM
New version volume controls polsol Parts 2 21st September 2004 01:16 PM
Separate Left & Right Volume Controls PTL60 Solid State 6 24th March 2002 11:28 AM


New To Site? Need Help?

All times are GMT. The time now is 09:58 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