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 8th April 2009, 04:45 AM   #1
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
Default Any recommendations for tube for vari-mu compressor?

Looking for a cheap tube to try for the front tube in a vari-mu compressor for a guitar amp, not a studio. I've already done a bunch of research:

Vintage tube compressors use the $$$ 6386 tube. I think a triode strapped 6BA6 is what is generally considered the best sub for that; it's even sold on the Manley Labs site. Yet on Fred Nachbaur's site he slammed the 6BA6 as often microphonic, and said the 6BJ6 is better. He used the 6JB6 in the Li'l 4x4 amp, and a 6K7 in the Dogzilla amp. There is also PRR's DIY vari-mu compressor which uses the 12AU7, but this design supposedly runs out of steam and can't deal with higher compression rates.

In any case, I'm looking for either a specific recommendation on a tube for this app, or at least a recommendation for a (very) remote cutoff pentode to try.
__________________
Aerodynamics are for people who can't build engines. Enzo Ferrari
  Reply With Quote
Old 8th April 2009, 05:08 AM   #2
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
6BA6 and 6K7 are "very" remote tubes, both 6BJ6 and 6J7 are less remote pentodes.
__________________
If I disappear suddenly, that means I finally created a time machine and pushed wrong button that brought me to Stalin's Russia. In any experiment any result is the result. Even if it is negative.
  Reply With Quote
Old 8th April 2009, 02:28 PM   #3
diyAudio Member
 
SpreadSpectrum's Avatar
 
Join Date: Nov 2007
Wasn't JJ going to make a 6386? I don't see it for sale anywhere, though. I have sales literature for it.
  Reply With Quote
Old 8th April 2009, 03:50 PM   #4
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Check this thread:
http://www.diyaudio.com/forums/showt...315#post951315

Don
__________________
I want a Huvr-Board!!
  Reply With Quote
Old 8th April 2009, 08:14 PM   #5
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
Quote:
Originally posted by smoking-amp
Check this thread:
http://www.diyaudio.com/forums/showt...315#post951315
Ah! I assume you mean using the 6BN6 as a "roll your own cutoff"? Sounds a bit challenging, but possibly VERY rewarding. The references to "accelerator", "limiter", and "quadrature" are somewhat intimidating. To dumb it down a bit, is there something wrong with a starting point of strapping g2 to the plate, and biasing g3 positive with a zener between it and the plate?

EDIT: thinking about it some more, couldn't you bias g3 to the point where it becomes a vari-mu expander?
__________________
Aerodynamics are for people who can't build engines. Enzo Ferrari
  Reply With Quote
Old 8th April 2009, 08:23 PM   #6
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
"Ah! I assume you mean using the 6BN6 as a "roll your own cutoff"?"

6BN6 looks complicated. But if you can figure it out....

I was thinking more along the dual control grid tubes. (You just put a control voltage proportional to signal envelope on g3 for compressor use. Or could just try direct biased up signal on g3 [and still g1] for some really potent distortion effects.)

Or, the many other remote cutoff tubes. George (Tubelab) mentioned the 6SK7 for instance, but there seem to be a bunch of others. 6SS7 for example. You need to rummage thru the GE Essential Characteristics book for them all.

Don
__________________
I want a Huvr-Board!!
  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
Tube Compressor Ahmad_tbp Tubes / Valves 42 1st March 2010 03:49 PM
Input tube recommendations... SpreadSpectrum Tubes / Valves 9 15th January 2009 07:41 PM
Schematic for tube compressor/sustain ? whatsnext Instruments and Amps 6 23rd August 2005 04:52 PM
Tube compressor problem! coony Tubes / Valves 7 1st February 2005 08:08 AM
Tube Cooling Recommendations gingertube Tubes / Valves 20 21st December 2004 07:52 AM


New To Site? Need Help?

All times are GMT. The time now is 12:55 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