More junk from China - 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 21st February 2011, 12:00 PM   #1
diyAudio Member
 
Join Date: Nov 2002
Default More junk from China

Why the 6SN7 attached to the power supply?
Attached Images
File Type: jpg 6sn7 diagram.jpg (41.6 KB, 1553 views)
  Reply With Quote
Old 21st February 2011, 12:23 PM   #2
diyAudio Member
 
Join Date: Oct 2002
Location: SINGAPORE
Quote:
Originally Posted by 6BG6GA View Post
Why the 6SN7 attached to the power supply?
why even bother with something u see as junk?
  Reply With Quote
Old 21st February 2011, 01:06 PM   #3
limono is offline limono  United States
diyAudio Member
 
Join Date: Mar 2007
Complex of a citizen of once industrial country
  Reply With Quote
Old 21st February 2011, 01:40 PM   #4
diyAudio Member
 
Ty_Bower's Avatar
 
Join Date: Mar 2007
Location: Newark, DE
Quote:
Originally Posted by 6BG6GA View Post
Why the 6SN7 attached to the power supply?
Maybe some kind of current regulator... though wouldn't a pentode be the usual choice?
  Reply With Quote
Old 21st February 2011, 01:54 PM   #5
diyAudio Member
 
kavermei's Avatar
 
Join Date: Jan 2005
Location: Lokeren, Belgium
Send a message via MSN to kavermei
Also, 300V half-wave rectified cannot possibly feed a 330V zener regulator
__________________
Never send a human to do a machine's job. --Agent Smith
  Reply With Quote
Old 21st February 2011, 02:21 PM   #6
diyAudio Member
 
Palustris's Avatar
 
Join Date: Aug 2006
Location: Cape Cod
It's a mini regulator. Bogen used the same thing for their screen regulators on some amps. The SRRP suffers from poor power supply ripple rejection so it could be a useful application of the regulator.
  Reply With Quote
Old 21st February 2011, 02:29 PM   #7
Bigun is offline Bigun  Canada
diyAudio Member
 
Bigun's Avatar
 
Join Date: Jan 2009
Blog Entries: 2
Looks like a kind of active bootstrap current source - it takes a signal from the cathode of the lower tube and since the cathode resistor is not bypassed it samples the signal.
__________________
"The test of the machine is the satisfaction it gives you. There isn't any other test. If the machine produces tranquility it's right. If it disturbs you it's wrong until either the machine or your mind is changed." Robert M Pirsig.
  Reply With Quote
Old 21st February 2011, 05:29 PM   #8
DF96 is offline DF96  England
diyAudio Member
 
Join Date: May 2007
My guess is a bootstrap voltage source, in order to reduce distortion? It won't improve PSRR, but probably make it worse by directly injecting HT noise into the input cathode.

300V RMS AC half-wave rectified gives 420V, so plenty to drive a 330V zener chain.
  Reply With Quote
Old 21st February 2011, 11:30 PM   #9
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Odd! It does seem the lower 6SN7 is driving the upper one. But it's the opposite phase of a typical voltage bootstrap. It lowers the plate voltage on the middle 6SN7 plate when the signal is rising toward +. Since the effect would be small: 1/Mu, thru the plate, I can only guess this is some scheme for affecting distortion. Notice the same size cathode resistors on the lower two 6SN7's. Simulation needed. Could maybe replace the topmost 6SN7 with a Mosfet for convenience.
__________________
I want a Huvr-Board!!
  Reply With Quote
Old 22nd February 2011, 07:23 AM   #10
rs7cai is offline rs7cai  China
diyAudio Member
 
Join Date: Feb 2010
Quote:
Originally Posted by 6BG6GA View Post
Why the 6SN7 attached to the power supply?

You really do not understand this circuit......
  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
I found more junk! Magnetmaz Tubes / Valves 9 28th December 2007 08:49 AM
New Chip Junk classd4sure Class D 85 20th September 2006 08:24 PM
Just got new junk from my friend Giaime Solid State 29 22nd March 2005 12:29 PM
got some interesting junk yosh Parts 2 27th June 2004 09:01 AM


New To Site? Need Help?

All times are GMT. The time now is 02:16 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