experimental 6L6G / 6BG6G amp design brainstorm - Page 4 - 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 20th March 2009, 12:59 PM   #31
diyAudio Member
 
whitelabrat's Avatar
 
Join Date: Dec 2006
Location: Maryland
I've been using 6BG6GA's in a Simple SE for a while now. You won't be disappointed. I've tried a pair of old 6BG6G's and they sounded great, but couldn't take the ~27w dissipation (guessing from tubelabs chart). The GA's may be able to take a good beating depending on the manufacture.

One thing about these 6BG6 tubes is they can take a good high voltage. Anyone have thoughts about using the 640vct power transformer with a bridge rectifier? Electrolytics probably aren't an option any more in a power supply, but they can be gotten reasonably
  Reply With Quote
Old 20th March 2009, 06:31 PM   #32
chromal is offline chromal  United States
diyAudio Member
 
Join Date: Feb 2005
Location: Evergreen, CO
Default 6L6G/6L6GB/6BG6G/6BG6GA SE OTs

So one of the questions on my mind is the ideal primary impedance for a 6BG6G SE OT. I've read different things, primarily,
6L6GB: A SE Zout = 4600
807: A SE Zout = 6000 for 'autobias resistor,' 5000 for -20v grid bias. autobias? Is that like cathode bias?

I've primarily been looking at Edcor OTs at the suggests of others here and because of their price/performance:

CXSE25-4-5K
CXSE25-4-6.5K

But am not sure which would be the best choice for tube/loudspeaker rolling (I have two pairs of 4ohm and three pairs of 8ohm loudspeakers, would ideally be able to explore both). Should I ask about two secondary output impedences, perhaps, or hook up 8ohm speakers to the 4ohm outputs and hope it's 'close enough' ?
  Reply With Quote
Old 20th March 2009, 06:49 PM   #33
diyAudio Moderator Emeritus
 
jean-paul's Avatar
 
Join Date: Sep 2002
Location: Germany
Chromal, could you send me a pm ?
__________________
It's only audio. Official member of the Norske Brillegeit Gang.
  Reply With Quote
Old 20th March 2009, 08:32 PM   #34
chromal is offline chromal  United States
diyAudio Member
 
Join Date: Feb 2005
Location: Evergreen, CO
Well, nevermind. I just ordered some Edcor XSE SE OTs. Ouch, 2-3wk turnaround. WEll, I'm glad they seem busy with orders in this economy. If they're not the best choice, ohwell, at least they were cheap at $20 per. (XSE15-4-5K) Although some 'net reviewers suggest they exceed their official specified bandwidth, I sort of balk at the official lofi-ish spec of 70-18kHz. Anyway, I can always drop in CXSE25-4-5K OTs later, if I want.

I also picked up an unlisted Edcor Power Transformer they had with 370-0-370@200mA, 6.3@4A, 5@2A) which I think will make a decent power supply tranny for my Simple SE / 6BG6G project. Still haven't figured out how I would power a stereo version of my 6BG6G class-A PP amp project, nor whether I want an integrated stereo amp or two monoblocks.... I'll continue to muddle forward with my 1-channel class-A PP prototype using my existing power and output trannys.
  Reply With Quote
Old 20th March 2009, 11:45 PM   #35
chromal is offline chromal  United States
diyAudio Member
 
Join Date: Feb 2005
Location: Evergreen, CO
Here, I've attached a .PNG image of the schematic and a simulation of a possible B+ supply for the 6BG6* class-A(triode) PP 1ch amp. a 4k resistive load is intended to represent two ~42mA (triode-strapped) anode loads on the PP transformer.

the white line is the voltage presented to the OT's primary center tap.

T1 is my 320-0-320@105mA power tranny (320@117 input. my input's more like 120-121, so 333-0-333 in the simulation)

L1 is a hammond 169S 4H 225ma 500v choke.

C1, C2, C3 are 500v caps. (note that C1 and C2 are shown as 'ringing' into the near 550v territory, but what design alterations I could make aren't clear to me...

R2 is intended to represent the OT/tube load at quiescent.

My goal here is to provide a ripple filter and current source for a 325v plate voltage, 42mA Ia per tube, as per the application data for a triode-strapped 6BG6G class-A P/P from tung-sol, which rates each tube at a Zout of 8000 under this configuration.

Is C3 enough of a reservoir at 47uF? I have a bag full of these 47uF@500wvdc electrolytics....
Attached Images
File Type: png 6bg6g-class_app.png (91.6 KB, 181 views)
  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
Experimental loudspeaker design -need criticsm BMD Multi-Way 12 15th October 2011 08:55 AM
Experimental Design - Comments, Flames Welcome Michael Rothacher Pass Labs 72 26th April 2011 10:34 AM
6L6G Amp recommendations 77seriesIII Tubes / Valves 13 21st November 2007 03:42 PM
Anyone build/use 6BG6G? kegger Tubes / Valves 12 28th February 2007 08:12 AM
Best driver for an experimental design BMD Full Range 12 12th May 2006 11:30 PM


New To Site? Need Help?

All times are GMT. The time now is 10:18 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