why does 12u7 need certain amount of gain to stop hum 120??? - 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 15th October 2008, 10:54 PM   #1
prorms is offline prorms  United States
diyAudio Member
Join Date: Nov 2006
Send a message via ICQ to prorms
Default why does 12u7 need certain amount of gain to stop hum 120???

why does 12ua7 need certain amount of gain to stop hum 120 hz ??
about 5% and up thd i do not hear the hum cycle .
  Reply With Quote
Old 16th October 2008, 04:33 AM   #2
diyAudio Member
Richard Ellis's Avatar
Join Date: Sep 2006
Location: Mar del Plata, a BIG seasonal getaway city, can see the Ocean from our residence.
Do you mean a 12AU7 right??
What circuit does it reside in?...I would guess the front end of an Amp or Pre-amp.
A 120 Hz audible hum is usually a power supply problem....Do you have a schematic we can all peruse??
______________________________________________Rick ..........
  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
Question about amount of feedback to apply Pyre Tubes / Valves 4 8th September 2007 01:29 PM
need a SPL box for a limited amount of space de57roy Car Audio 3 24th August 2007 05:38 PM
acceptable amount of ripple for AlephX PS nobody special Pass Labs 4 27th February 2003 08:56 PM
calculating amount of current hacknet Solid State 17 2nd December 2002 06:13 AM

New To Site? Need Help?

All times are GMT. The time now is 02:08 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