Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Revox MR8 PSU unstable
Revox MR8 PSU unstable
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 29th October 2017, 11:30 AM   #1
terremotor is offline terremotor  Spain
diyAudio Member
Join Date: Dec 2006
Default Revox MR8 PSU unstable

Hi guys. I have a problem with the power supply of a small console Revox MR8.
When it has a circuit load, the -15v voltage drops slowly and is maintained at -13v. insufficient for adjustments.
See the PSU with LM337 regulator:
Attached Images
File Type: jpg 0001.jpg (691.6 KB, 55 views)
  Reply With Quote
Old 3rd November 2017, 02:54 AM   #2
anatech is offline anatech  Canada
diyAudio Moderator
anatech's Avatar
Join Date: Jun 2004
Location: Georgetown, On
Revox MR8 PSU unstable
Hi terremotor,
Have you checked the supply for the -15V regulator? Use an oscilloscope to see if the regulator is dropping out. I find that the capacitors Revox used are failing right about now.

"Just because you can, doesn't mean you should" my Wife
  Reply With Quote
Old 8th December 2017, 05:39 PM   #3
terremotor is offline terremotor  Spain
diyAudio Member
Join Date: Dec 2006
I have replaced some components. There was a bad rectifier diode.
I have also found some transformers with secondary open in preamplifier
I'm surprised, I do not understand why open transformer T100...
Studer Revox mr8 pre.jpg
  Reply With Quote


Revox MR8 PSU unstableHide 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
Unstable buffer Elvee Solid State 76 1st September 2014 08:20 PM
unstable right channel windscreen Tubes / Valves 5 12th November 2013 07:12 PM
Revox B-201 Remote: Will it work with a B-126 Revox CD Player dtm1962 Digital Source 2 3rd August 2010 02:20 AM
fizzy and unstable DrStrangelove Tubes / Valves 29 12th December 2007 05:50 AM

New To Site? Need Help?

All times are GMT. The time now is 07:02 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio