Go Back   Home > Forums > Amplifiers > Tubes / Valves

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
Reply
 
Thread Tools Search this Thread
Old 18th May 2010, 11:59 PM   #1
diyAudio Member
 
Join Date: Sep 2009
Default Noisy input on Michaelson & Austin TVA-1

Hello,

Anyone ran into this before? On the input board schematic there are .022 and 5 pF capacitors, which seem to be the likely suspects for causing a small buzzing noise being fed to the output stage. Any ideas on what other caps it might be? I know I could just replace all the caps, diodes and pots, but has anyone worked on this amp before? A service manual would be greatly useful.
Has anyone seen one available? TIA...

pix4work
  Reply With Quote
Old 19th May 2010, 12:10 AM   #2
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Here's a schematic:

Schematic - Michaelson & Austin TVA-1 Tube Amplifier @ AmpsLab.com

The caps you mention would be unlikely suspects. What sort of buzz is it? 100/120 Hz sawtooth? Both channels?
__________________
"It is difficult to get a man to understand something, when his salary depends upon his not understanding it." Upton Sinclair
  Reply With Quote
Old 19th May 2010, 01:09 AM   #3
diyAudio Member
 
Join Date: Sep 2009
Default http://www.diyaudio.com/forums/tubes-valves/167103-noisy-input-michaelson-austin-tva-

It's higher than 120 Hz., maybe up around 400 Hz. and it's in both channels.
  Reply With Quote
Old 24th September 2011, 09:24 AM   #4
diyAudio Member
 
Join Date: Jul 2010
Hi,
Please check the grounding which is highly possibly the cause of the hum.
  Reply With Quote
Old 24th September 2011, 12:11 PM   #5
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
Yes, if its on both channels then either grounding or something in the PSU.

Blindly changing caps etc. is a good way to introduce new faults. If your doctor tried to cure you by just working though all the common medicines at his disposal you might be concerned; diagnosis ought to precede treatment!
  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
Michaelson & Austin TVA-1 info JDeV Tubes / Valves 65 20th September 2013 02:34 AM
Michaelson and Austin Oddysee lpd Tubes / Valves 17 10th August 2010 01:19 PM
Wanted - Michaelson & Austin TVA-10 Miab Swap Meet 1 11th February 2009 03:31 AM
Noisy Input Pot : Lexicon Reflex yekuku Digital Source 2 13th December 2006 10:22 PM
michaelson & austin tva 10 TJ Tubes / Valves 6 24th April 2003 01:56 PM


New To Site? Need Help?

All times are GMT. The time now is 12:45 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