Circlotron amps - 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 23rd April 2004, 10:06 PM   #1
diyAudio Member
 
Join Date: Apr 2004
Location: Milky Way
Default Circlotron amps

I find this circuit topology interesting, but howcome it's not used more?
  Reply With Quote
Old 23rd April 2004, 11:06 PM   #2
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Mainly because of cost IMO.

Cheers,
__________________
Frank
  Reply With Quote
Old 24th April 2004, 12:04 AM   #3
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Complex power supplies. Very high drive requirements. Nonetheless, it's a circuit that I think deserves more attention.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 24th April 2004, 12:58 AM   #4
diyAudio Member
 
Join Date: Sep 2003
Location: Texas
I'm building two 80W circlotron monoblocks. At some point I'll report on them.

I don't think they are more complicated than SRPP output stages (futtermans). In fact, I think that they can be simpler, depending on the specific design. For one thing, they only need one bias supply, not two. And they don't suffer from the unbalanced drive issue.

Depending on the design, they can need more drive signal because the degenerative feedback is active on both sets of cathodes.

Their native Zo is a little higher than a properly designed Futterman, but in cases where NFB is applied (and this is probably most cases), this gap is reduced to being almost negligible.
  Reply With Quote
Old 24th April 2004, 03:19 AM   #5
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Heh, a perfect example of the same text meaning two things to two different people! I interpreted the question in light of transformer coupling, e.g., the classic EV Circlotron.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 24th April 2004, 01:36 PM   #6
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
I don't think they are more complicated than SRPP output stages (futtermans).
I suppose you mean SEPP, not SRPP?

Quote:
I interpreted the question in light of transformer coupling, e.g., the classic EV Circlotron.
So do I but it's still the same thing IMO...

Cheers,
__________________
Frank
  Reply With Quote
Old 24th April 2004, 06:10 PM   #7
diyAudio Member
 
smoking-amp's Avatar
 
Join Date: Dec 2001
Location: Hickory, NC
Default Practical Circlotron

Practical problems of the Circlotron include the high drive signal requirement due to the 50% cathode drive, lack of suitable off the shelf transformers with low primary impedance, and the need for dual floating plate power supplies with low common mode capacitance to ground and to each other (in addition to a third plate supply for the front end section).

Most of the practical difficulties of a Circlotron can be overcome with the following circuit variations (Elliptron):

Elliptron Schematic

Using 40% taps gets the cathode drive down to 28%, reducing drive requirement from very difficult to just challenging. The plate impedance per tube is (1 + 0.4)/2 squared, times the end to end impedance rating of the transformer.
The Hammond 1650T is a reasonable choice for the Elliptron configuration. (By the way, I generally derate Hammond P-P transformers by 50% power wise to get the mag. flux density level down into the linear 7500 gauss max. region for HIFI. The given Hammond ratings appear to be near max saturation level for guitar amp. use.) I use two, cheap, "dual bobbin" industrial step up xfmrs. for the low capacitance floating supplies, with separate filter inductors mounted on insulating standoffs. For the conventional single supply version I use a small, dual 240V winding, industrial step up xfmr for the center tapped cathode inductor.

Don
__________________
I want a Huvr-Board!!
  Reply With Quote
Old 25th April 2004, 01:31 PM   #8
diyAudio Member
 
A3rd.Zero's Avatar
 
Join Date: Nov 2003
Location: Los Angeles
http://www.audiodesignguide.com/index_nobanner.html

is a great sight by Andrea Ciuffoli, where he talks about Circlotron amps in a good bit of detail. Specifically in the OTL section.

Milo

edit: I found it hard to find my way back through the website so here is the actual page
http://www.audiodesignguide.com/otl/
__________________
How did I live without Nina Simone for so long?
  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
6S19 Circlotron (OTL) Fuling Tubes / Valves 62 13th November 2008 11:16 AM
Simple circlotron amp bigwill Tubes / Valves 4 18th March 2007 01:57 PM
Circlotron djk Pass Labs 13 20th August 2006 03:19 AM
6C33 Circlotron pat49hk Tubes / Valves 50 26th January 2006 09:06 AM
Supersymmetry Circlotron Circlomanen Pass Labs 6 18th April 2005 06:34 AM


New To Site? Need Help?

All times are GMT. The time now is 11:16 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