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

Noise problem in 572-10 PP amplifier
Noise problem in 572-10 PP amplifier
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 22nd March 2010, 12:36 AM   #21
Michael Koster is offline Michael Koster  United States
diyAudio Member
 
Michael Koster's Avatar
 
Join Date: Jan 2008
Location: Sunnyvale, CA
The heater thing was a long shot... damper diodes are rated for the cathode being +900V wrt the heater so the heater could also be grounded in this case.

I still don't know if I would put them on the same string as gain stage tubes. I guess maybe if they had a low impedance ground.

Good to hear the noise has gone. It must have been the wiring?

Cheers,

Michael
  Reply With Quote
Old 22nd March 2010, 03:28 AM   #22
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Noise problem in 572-10 PP amplifier
Quote:
Originally Posted by Michael Koster View Post
The heater thing was a long shot... damper diodes are rated for the cathode being +900V wrt the heater so the heater could also be grounded in this case.

I still don't know if I would put them on the same string as gain stage tubes. I guess maybe if they had a low impedance ground.

Good to hear the noise has gone. It must have been the wiring?

Cheers,

Michael
Good to know, and FWIW I generally don't put rectifier heaters on the same string as small signal tubes, but it has been done in the past - most commonly in tubed tuners and pre-amplifiers. (Scott and Fisher both did this)
__________________
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 22nd March 2010, 10:50 PM   #23
santa is offline santa  United States
diyAudio Member
 
Join Date: Mar 2003
Location: California
My photo host has been down for a while so I am only
now able to post a shot of the underside

Click the image to open in full size.


The lower left hand corner of the amp is an electrically noisy place.
Cleaning this up and moving the feedback line and rotating the pot so the terminals were as far away as possible from where the wires from the power transformer go through thetop plate was the cure.

Noise is about 5 mV PP pretty much a combination of 60 Hz, something else and I can see the spike still is lurking although at much lover levels.

I am using AC on the 572-10's filaments.
Still a lot to do here.
I want to remove the two black resistors that are hanging in space and use one of those gold aluminum ones. I'll form a L bracket to hang it on and sink a bit of heat as well.

There are numerous other little problems that will be adressed as I go.

Next thing to work on is square wave response.
It looks pretty good right now with a bit of peaking on the leading egge but no ringing, just a gradual tilt which is not too sharp.

Thanks again for the help, suggestions and inspiriation to persevere and tackle the issue.

Cheers!
  Reply With Quote

Reply


Noise problem in 572-10 PP amplifierHide 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
PP oscillation problem DHT112A Tubes / Valves 7 5th December 2009 11:02 PM
6L6 PP problem slideman82 Tubes / Valves 2 2nd November 2009 09:45 AM
SL-10 Noise hifi-hospital Pass Labs 8 16th February 2009 09:23 PM
SV 572-3 tubes to go krzys Swap Meet 3 9th September 2004 02:46 PM
6L6GC PP Problem PassFan Tubes / Valves 4 29th September 2003 02:30 AM


New To Site? Need Help?

All times are GMT. The time now is 08:21 PM.


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
Wiki