FISHER - 500b Caps Leave Them In ??? FISHER - 500b Caps Leave Them In ??? - diyAudio
Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

FISHER - 500b Caps Leave Them In ???
FISHER - 500b Caps Leave Them In ???
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
Thread Tools Search this Thread
Old 26th September 2009, 03:52 PM   #1
ricerkt_61 is offline ricerkt_61
diyAudio Member
Join Date: Sep 2009
Default FISHER - 500b Caps Leave Them In ???

So I got this Fisher 500b off ebay last year. It had one channel not talking.
I was hoping for an easy tube swap fix. But that's not the way it worked out.
I wound up replacing the multi-part condensor attached to the treble pot..

I did rebuild the B+ power supply sections now my finals aren't frying.

Last night I replaced 2 stock caps in the tone control amp section. C14 and C15 with 2 sprague Orange Drops. .022uf/600v...
Powerd it back up and immediately noticed the audio sounds crappy. I was amazed. I was going to put the old ones back in but I clipped those right up to the point where they couldn't be used again. It was late, I was tired and a little pissy. This morning I get up and turn it on and was surprised again. A drastic difference. Now hearing things I wasn't before, for the better. Last night it was like the mids kinda rolled off into a little grainy sound. now I'm thinking I was hearing things.

Anyway, the main question here. I have more of these to replace in the amplifier section but wonder if I should. What is the problem with leaving the old stock ones in there?
  Reply With Quote
Old 27th September 2009, 11:02 PM   #2
dynacopas is offline dynacopas  United States
diyAudio Member
Join Date: Sep 2009
The prob with old stock ones is they have drifted out of spec in most cases and may leak in some cases as well. As for the changes in sound thats the caps burning in. I wouldn't pass judgement until the new caps burn in which is minimum 10 hours playing time. There will be many that disagree with cap burn in but I am a firm believer. A full recap would benefit you immensely and get the amp ready for the next 25 years. The only other danger is if a cap pops and put a bunch of wax and oil all over the inside of the chassis which is a big mess to clean. If your unit has matched pairs of bias resistors I would replace them that is almost mandatory. Look for the asterisk next to a pair of resistors and those are the matched pairs. Just my opinion. Hope that helps.
  Reply With Quote


FISHER - 500b Caps Leave Them In ???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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
OK To Leave X600.5 On Continuously? DarqueKnight Pass Labs 22 1st December 2007 09:36 PM
Fisher 500B Schematic Question wrenchone Tubes / Valves 5 23rd August 2006 11:57 PM
Fisher 500B OPT/Feedback Questions wrenchone Tubes / Valves 22 16th December 2005 10:06 PM
Need help with caps for my 1960 fisher JH Tubes / Valves 7 4th January 2003 10:48 PM

New To Site? Need Help?

All times are GMT. The time now is 12:51 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio