Output stage opinions - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

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 18th February 2008, 06:42 AM   #1
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
Question Output stage opinions

Hi

Recently I have successfully used an output circuit similar to Mr. Cordell's Hex-Fet EC output stage. I have made some modifications, on paper, to my circuit that I think may work better. The VAS is biasing the +/-11V DC and provides up to +/-22V signal swing (up to 33V) max, adequate for clipping.
My thoughts are to use higher frequency, small signal transistors to increase the bandwidth of the error correction amplifiers. Also, I added a cascode for the first pre-driver and last driver transistors so as to have a constant Vce, and to be able to use small signal, low noise, fast devices for these and still be well within their SOA. The output fets have a Vgs threshold of about 3.5V. The two Vgs multiplier transistors (SOT-23) could be mounted so as to be in contact with the drain lead of the output transistors to sense die temperature. Something like this example
I am thinking it should work well, but I thought I might try to get a second (or more) opinion. Is there any reason this wouldn't work?

The transistors I plan to use are:
KSC2223
MMBTH81
FJV1845
KSC1845
KSA992
FJV992
BC850
BC860

and these 'space savers' from On-Semi, labeled 1/2 and 2/2.:
EMX1DXV6T1-D
EMT1DXV6T1-D

Thanks
Attached Images
File Type: jpg output stage.jpg (77.4 KB, 359 views)
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 18th February 2008, 08:21 AM   #2
CBS240 is offline CBS240  United States
diyAudio Member
 
CBS240's Avatar
 
Join Date: Aug 2005
Location: K-town
Or is this circuit better?

The difference is where the base bias for the Vbe multiplier comes from....
Attached Images
File Type: jpg output stage.jpg (87.4 KB, 291 views)
__________________
All the trouble I've ever been in started out as fun......
  Reply With Quote
Old 18th February 2008, 05:40 PM   #3
diyAudio Member
 
myhrrhleine's Avatar
 
Join Date: Jan 2006
Location: Avalon Island
Mr Cordell is on this forum.
You could PM him directly.

Also, he recenty posted, the faster the xistors, the better.
See his ongoing discussion on EC.

Bob Cordell Interview: Error Correction
__________________
Just because you can't hear it doesn't mean no one can.
  Reply With Quote
Old 18th February 2008, 08:53 PM   #4
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Myhrrhleine,

Is that really you in the avatar, looking remarkably Basinger on the sofa?

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 18th February 2008, 09:14 PM   #5
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Man... i have almost fell down from my chair watching this avatar



My God!

Beautifull!

The problem is that if you go to check..ahahahah..will find a seven foot high male with a big moustache asking you if you wanna a kiss.

ahahahahaha!

I do not want!

regards,

Carlos
Attached Images
File Type: jpg 100_0249.jpg (39.6 KB, 138 views)
__________________
This Sunday assemble a toy amplifier....a good fun to your weekend; https://www.youtube.com/watch?v=yk0qvkwsAOY
  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
New gain stage .. Opinions??? nitrate Tubes / Valves 4 26th January 2009 01:02 PM
3C24 in a SE output stage - output transformer impedance recommendation !!! aldovan Tubes / Valves 15 6th September 2008 10:18 AM
Output stage biasing, with the driver stage andrew_whitham Tubes / Valves 0 19th May 2007 11:14 AM
Adding secondary of output transformer into cathodes of output stage ? Eico ST-70 freddymac406 Tubes / Valves 3 21st April 2007 06:15 PM
Curcio Sarah Phono stage: opinions? ad010685 Tubes / Valves 4 8th August 2006 12:30 PM


New To Site? Need Help?

All times are GMT. The time now is 04:03 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