Futterman style 6AS7 OTL with other tubes - 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 17th July 2009, 04:52 PM   #31
diyAudio Member
 
whitelabrat's Avatar
 
Join Date: Dec 2006
Location: Maryland
It's a Solen PPB. ASC makes very large ones too. I've got a couple 600uF's sitting in a box somewhere. I could probably get away with driving speakers with those although their dropoff would be at 33Hz at 8 ohms.
  Reply With Quote
Old 17th July 2009, 05:04 PM   #32
diyAudio Member
 
Join Date: Jan 2003
Location: Sweden
Quote:
For example I was thinking of the 6CG7 where they would be only good for a couple milliwatts of output, but let's say I had 10 tubes in parallel for one channel. That's 20 triodes in action which would bring down the output resistance, and add up to a couple of watts to the output. I didn't say it was practical, just possible.
Yes, it is possible and can be made practical if you take care of distributing the current between all tubes, this can be done by matching all tubes and by using cathode resistors for each individual tube to avoid "current hogging" i.e. where one tube takes to high current, thereby failing and thereby making other tubes take to high current and so on...

Even when individual cathode resistors are used the current for parallel connected tubes should be reduced, figures for de-rating where given for regulator tubes in data sheets, (6AS7, 6C33C) typically the current for each tube was only half when 4 or more where used in parallel.

It is my understanding that the reliability problems of most commercial OTL amplifiers are due to a combination of running tubes way above ratings or no or too low de-rating of tubes when parallel connected.
  Reply With Quote
Old 17th July 2009, 06:36 PM   #33
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Quote:
It's a Solen PPB. ASC makes very large ones too
Solens are a little on the pricey side. 330uF film 99 USD. That will be one expensive headphone amp.

Couldn't find much for ASC caps (found their home page). How much do they run for?
  Reply With Quote
Old 17th July 2009, 06:41 PM   #34
diyAudio Member
 
leadbelly's Avatar
 
Join Date: Dec 2002
Location: Calgary, Alberta
Quote:
Originally posted by Brit01
That will be one expensive headphone amp.
Find one that is at a good price point, highest C / $, and parallel a bunch of them.
__________________
Aerodynamics are for people who can't build engines. Enzo Ferrari
  Reply With Quote
Old 17th July 2009, 07:10 PM   #35
diyAudio Member
 
whitelabrat's Avatar
 
Join Date: Dec 2006
Location: Maryland
Someone is selling them at $7.50 a pop on ebay. Buy two, get one free. Crazy good deal. It's the ASC GLY513. Just seach ebay for "ASC 600"
  Reply With Quote
Old 17th July 2009, 11:30 PM   #36
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
Originally posted by Brit01


Solens are a little on the pricey side. 330uF film 99 USD. That will be one expensive headphone amp.

Couldn't find much for ASC caps (found their home page). How much do they run for?
What exactly is it you want to buid?

Do you want this amp to drive speakers or headphones?

TIA,
__________________
Frank
  Reply With Quote
Old 18th July 2009, 12:08 AM   #37
Brit01 is offline Brit01  United Kingdom
diyAudio Member
 
Join Date: Jul 2008
Quote:
What exactly is it you want to buid?
We did get sidetracked a little.

Initial thread was for speakers but then I asked about the 100uF film output cap as I have built a headphone amp with electrolytics.

Sorry to confuse you.
  Reply With Quote
Old 22nd July 2009, 12:36 PM   #38
diyAudio Member
 
Join Date: Dec 2004
Location: NE USA
Quote:
[i] PICS of the monsters are on the forum ... [/B]

Coresta

Can you tell me where on the forum pictures of your monsters can be found? I would love to see them? Any schematic available? Thx in advance
  Reply With Quote
Old 22nd July 2009, 04:16 PM   #39
coresta is offline coresta  France
diyAudio Member
 
coresta's Avatar
 
Join Date: Mar 2005
Location: Paris
somewhere in the "pictures gallery " file , or here , from Wagtbtoobz, my other french id : http://retro-forum.com/viewtopic.php?t=13883 in french ... many pictures and schematic published Cheers
Pierre
  Reply With Quote
Old 22nd July 2009, 05:04 PM   #40
tyu is offline tyu  United States
diyAudio Member
 
Join Date: Jul 2009
Default eze OTL too diy an its a Circ lotron,

All parts an tubes an xfourms for two monos less than $500,
this has been up on the OTL site the King of OTL put it up not me
  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
Futterman H-3 desperateaudio Tubes / Valves 35 23rd April 2009 04:37 AM
Technics variation of Futterman SEPP. Circlotron Tubes / Valves 38 12th December 2008 03:54 PM
Octal tubes for 7695-style matrix amp? bst Tubes / Valves 3 15th November 2006 08:52 AM
Futterman OTL ferrite bead specification jwan Tubes / Valves 4 15th March 2004 07:17 PM
Improving the Futterman Sch3mat1c Tubes / Valves 6 18th August 2003 10:35 PM


New To Site? Need Help?

All times are GMT. The time now is 09:31 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