6V6 line preamp - Page 52 - diyAudio
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 19th February 2012, 05:56 PM   #511
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Is it possible that having wired this way is affecting thevregulator? With sense wires connected to B+ and G, i get a B+ of 370. With them jumpered at the reg, 340 B+.
  Reply With Quote
Old 19th February 2012, 06:06 PM   #512
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
I was reversing the speakers polarity at power amp terminals whenever I had an inverting stage in the chain.
  Reply With Quote
Old 19th February 2012, 06:11 PM   #513
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Quote:
Originally Posted by buzzforb View Post
Is it possible that having wired this way is affecting thevregulator? With sense wires connected to B+ and G, i get a B+ of 370. With them jumpered at the reg, 340 B+.
There is indeed some difference on impedance points it shows. Set scope on AC input and hang the probe from B+ and put its crock on gnd. Go 5mV/div and scan time/div from left to right. If you will see a straight line thin enough and no waveform or thick fuzz then B+ rail is adequate.
  Reply With Quote
Old 19th February 2012, 06:39 PM   #514
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Switched polarity of outputs leaving phase reversal. Trimmed voltage with everything hooked up to 340. Switching outputs stopped oscillation. Filaments are 6.07 and 5.99. Offset of about 20mV. Here we go.
  Reply With Quote
Old 19th February 2012, 06:43 PM   #515
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
It wasn't oscillation then. It was wrong output connection. Heat on sinks ok? Any picture?
  Reply With Quote
Old 19th February 2012, 08:22 PM   #516
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
Hooked it up. Numbers are perfect. Offset les than 12mV. Muted sound.
Here are some numbers. Cant think straight so taking a break.
RL=127V both
Rscreen=.36 and .42
Rs =14.6 both
  Reply With Quote
Old 19th February 2012, 08:29 PM   #517
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
What do you mean muted sound? Low level?
  Reply With Quote
Old 19th February 2012, 08:59 PM   #518
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
yes. I will check solder joints, but all looks good with multimeter.
  Reply With Quote
Old 19th February 2012, 10:04 PM   #519
Salas is offline Salas  Greece
diyAudio Chief Moderator
 
Salas's Avatar
 
Join Date: Oct 2002
Location: Athens-Greece
Should give about 15dB gain. Feed it a sinewave and check output on scope.
  Reply With Quote
Old 19th February 2012, 10:46 PM   #520
diyAudio Member
 
buzzforb's Avatar
 
Join Date: Oct 2010
Location: Burlington, NC
I can hear music from my preamp with no speakers. This is awesome.....or terrible
  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
Help me design my DAC/Line Preamp. kuroguy Tubes / Valves 7 2nd April 2009 08:31 PM
preamp line ctt richwalters Tubes / Valves 1 7th March 2008 04:34 PM
Preamp for Line In and Mic blur Instruments and Amps 1 4th January 2007 04:02 PM
Line stage preamp, based on SY's "Heretical Unity gain line stage" Danko Tubes / Valves 23 18th July 2005 04:07 AM
Line preamp for 2A3 amp Petman Tubes / Valves 0 24th May 2002 03:11 PM


New To Site? Need Help?

All times are GMT. The time now is 02:04 PM.


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