One channel louder than other - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs 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

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 31st July 2010, 04:41 AM   #1
loudel is offline loudel  Australia
diyAudio Member
Join Date: Jul 2010
Default One channel louder than other

My Music Angel running 4KT88 in p/p has one side (channel) louder than the other. A little more info- the system has been running on and off for several months then one channel died. Took it to my Chinese 2nd hand audio repairer who replaced 4 (2x2) 3w resistors with 5w. Sound is back but noticebly less on the repaired channel. Have change the speakers/cables and outputs to no avail. I'm not very savvy about the inner workings but not afraid to change caps if need be (after draining them).Huffing it the repairer is a real chore as the unit weighs some 25k and I have to cart the thing in a suitcase on a plane.
Any suggestions?
  Reply With Quote
Old 31st July 2010, 05:10 AM   #2
TheGimp is offline TheGimp  United States
diyAudio Member
TheGimp's Avatar
Join Date: Aug 2009
Location: Johnson City, TN
1st I'd try switching tubes between channels, If you don't find any differences then start taking measurements.

I would recommend ohm-ing out all resistors and comparing the good to the low channel.

If no differences are found, then I'd measure the Output transformers and look for shorts. The problem is that the DC Resistance may be off considerably between channels. You will have to use a signal generator to verify winding ratios.
  Reply With Quote
Old 31st July 2010, 05:19 AM   #3
tinitus is offline tinitus  Europe
diyAudio Moderator R.I.P.
Join Date: Nov 2005
maybe check your attenuator

bias ?

voltage ?
sometimes we know very little, and sometimes we know too much
  Reply With Quote
Old 31st July 2010, 05:51 AM   #4
loudel is offline loudel  Australia
diyAudio Member
Join Date: Jul 2010
Thanks, fellas, I had posted a similar query as I thought this 1st post did not get through. Will check and get back but it'll take me a bit of time.The guts of the Music Angel seem quite over-engineered compared to other (usually older) valve amps. Should the fault not be dtectable then I have a good mind to replace everything except the transformers and valves with simpler circuitry - there are several schematics floating around.
  Reply With Quote
Old 31st July 2010, 10:58 AM   #5
loudel is offline loudel  Australia
diyAudio Member
Join Date: Jul 2010
Just an adjunct: have rolled the KT88s but same channel playing up. Then rolled the 12au/ats and seem to notice a small improvement in sound from affected channel.Could be onto something here - I have a couple of spare 12au/at and will roll them later this weekend.Fun.
Cheers and thanks.
  Reply With Quote


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
NAD 7100 / 3100 - one channel louder than the other mashley_nad Solid State 10 7th September 2010 06:05 PM
Why music really is getting louder ash_dac Digital Source 5 5th June 2007 09:44 AM
One Channel of JLH 80w Mosfet Louder than other foxyb Solid State 2 12th October 2004 01:14 AM
One channel is louder than the other? ble0t Chip Amps 30 12th June 2004 04:04 AM
One channel louder... Rotel RA-971 rsdent Solid State 3 22nd April 2004 04:09 AM

New To Site? Need Help?

All times are GMT. The time now is 02:29 PM.

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

Content Relevant URLs by vBSEO 3.3.2