Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Solid State Talk all about solid state amplification.

Winfield's 100W DC-10MHz 1000V/us amplifier
Winfield's 100W DC-10MHz 1000V/us amplifier
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 21st January 2018, 11:35 AM   #21
tiefbassuebertr is offline tiefbassuebertr  Germany
diyAudio Member
 
tiefbassuebertr's Avatar
 
Join Date: Jul 2005
Location: D-55629 Schwarzerden
Quote:
Originally Posted by winhill2 View Post
Rather than continue and extend a fragmented discussion on other threads, I'm starting a new one to discuss my amplifier design, the AMP-70. Fast slew rates are desirable for audiophile amplifiers, for better transient response. My 1000V/us amplifier, which can deliver 100W rms into 8 ohms, could be thought of as an awesome hi-fi amp, but it's really just a laboratory amplifier designed to deliver a full output swing up to 5MHz, even into capacitive loads. (I've included some reduced-size images in this post, the full versions are in the Dropbox folder linked below.)

An externally hosted image should be here but it is no longer accessible. Please upload images instead of linking to them to prevent this.


The design is based on the output amplifier in the Tektronix PG508 50MHz pulse generator. We examine this in detail as a Designs-by-the-Masters section in our upcoming book, The Art of Electronics, x-Chapters. I've included this 4-page section in the Dropbox link below. Here's the schematic.

An externally hosted image should be here but it is no longer accessible. Please upload images instead of linking to them to prevent this.


Basically there's an input stage creating a push-pull error current into a folded-cascode VAS stage, and emitter-follower outputs. The secret for fast slewing is to use a high 60mA VAS current with low Ccb capacitance transistors, for a fast slew rate S = i/C = 3000V/us for the PG508. The Tek pulse generator only had to deliver 0.2A to its load, whereas I have to deliver 5A, so I'm using larger, higher-capacitance transistors. Following the principle, F.O.M. = Pd / Ccb, to improve the slew rate, I selected low-capacitance types. They're fragile and I'm using 20, to limit their power dissipation.

An externally hosted image should be here but it is no longer accessible. Please upload images instead of linking to them to prevent this.


My amplifier design is somewhat more complicated, with various features to increase its capabilities, which we can discuss. Here's a dropbox link to my AMP-70A-2 schematic and related files for you to look over. Dropbox - AMP-70_DIY
Circuit topology looks similar to this amp:
stereoplay 1988 Monoblock from GŁnter Mania
for schematic go to post #4 under
Has anybody Burmester or AVM schematics?
  Reply With Quote
Old 22nd January 2018, 02:06 AM   #22
winhill2 is offline winhill2  United States
diyAudio Member
 
winhill2's Avatar
 
Join Date: Aug 2008
Location: Cambridge, MA USA
Wow, thanks for the lead. That's very interesting, the complementary pair of transconductance input error stages, each using a complementary pair of BJTs, and the folded-cascode VAS stage, is the same as in my amplifier. The devices and operating currents are of course quite different.

As I mentioned, I got the idea from the 50-ohm output amplifier in the Tektronics PG508 50MHz pulse generator. It uses the same input-stage circuit. This circuit has the advantage of being very fast, because it can run at high currents and doesn't require mirrors or high-gain common-emitter stages. It doesn't have very high open-loop gain, and the folded cascode stage, with pullup resistors instead of current sources, has some intrinsic distortion. So even though it has a blisteringly-fast slew rate, an audiophile would find things to criticize. But it makes an amazing DC-10MHz lab power amplifier. Several are in use now, generating quadrature electric fields for electro-rotation experiments, running at several hundred volts (with the help of a transformer) at 2.5MHz.

My earliest copy of the PG508 manual is dated Nov, 1975. My schematic copies are rev B, dated 1980. I have a 1986 catalog with a PG507 and PG508 datasheet page. Yessir, those Tektronix engineers were pretty advanced for their time!
  Reply With Quote
Old 16th February 2018, 01:34 PM   #23
as_audio is offline as_audio
diyAudio Member
 
Join Date: May 2008
Sorry the pictures in post 1 are not visible any more.
  Reply With Quote
Old 16th February 2018, 04:27 PM   #24
FdW is offline FdW  Netherlands
diyAudio Member
 
FdW's Avatar
 
Join Date: Feb 2009
Location: Both feet on the ground (near Gouda)
Winfield's 100W DC-10MHz 1000V/us amplifier
Quote:
Originally Posted by as_audio View Post
Sorry the pictures in post 1 are not visible any more.
You can always attach new ones e.g. The thread owner can always update the first message of the thread.
  Reply With Quote
Old 16th February 2018, 08:35 PM   #25
as_audio is offline as_audio
diyAudio Member
 
Join Date: May 2008
Ich nicht, Frans ..
  Reply With Quote
Old 17th February 2018, 09:40 AM   #26
FdW is offline FdW  Netherlands
diyAudio Member
 
FdW's Avatar
 
Join Date: Feb 2009
Location: Both feet on the ground (near Gouda)
Winfield's 100W DC-10MHz 1000V/us amplifier
Ooops... then ask one of the moderators, I'm sure he/she will help

I would like to see those pictures
  Reply With Quote
Old 17th February 2018, 10:12 AM   #27
thimios is offline thimios  Greece
diyAudio Member
 
Join Date: Aug 2009
Location: Agrinion
Quote:
Originally Posted by FdW View Post
Ooops... then ask one of the moderators, I'm sure he/she will help

I would like to see those pictures
Me too!
  Reply With Quote
Old 17th February 2018, 02:55 PM   #28
fmmech_24 is offline fmmech_24  Austria
diyAudio Member
 
Join Date: Aug 2009
Location: East-Tyrol
Winfield's 100W DC-10MHz 1000V/us amplifier
..mouse..right click..open in new tab, works fine.
  Reply With Quote
Old 17th February 2018, 03:36 PM   #29
as_audio is offline as_audio
diyAudio Member
 
Join Date: May 2008
You are our hero.
  Reply With Quote
Old 17th February 2018, 05:38 PM   #30
Mark Johnson is offline Mark Johnson  United States
diyAudio Member
 
Mark Johnson's Avatar
 
Join Date: May 2011
Location: Silicon Valley
Winfield's 100W DC-10MHz 1000V/us amplifier
Attached below in case dropbox changes their terms of service AGAIN.

_
Attached Images
File Type: jpeg AMP-70A_3D_small_preview.jpeg (131.6 KB, 526 views)
File Type: png Fig-2x.78_PG508_5ns-amp_preview.png (221.6 KB, 594 views)
File Type: jpeg AMP-70A_top_small_preview.jpeg (134.0 KB, 585 views)
  Reply With Quote

Reply


Winfield's 100W DC-10MHz 1000V/us amplifierHide 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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
TDA7498 100W+100W Class D Amplifier comasus Class D 1 18th November 2015 09:05 PM
Sure Electronics AA-AB33182 [4 x 100W] Class D Audio Amplifier Board +27V DC Power... fualcr Swap Meet 5 11th December 2014 08:32 PM
Best amplifier board (100W + 100W) (<50$) H3x0S Class D 5 18th October 2012 05:05 PM
12v dc to dc 100w psu razordave123 Power Supplies 13 7th February 2006 04:29 PM
AKSA 100W Kitset Amplifier and VAF DC-X's??? sgamma2002 Solid State 2 19th August 2002 08:35 AM


New To Site? Need Help?

All times are GMT. The time now is 08:34 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 14.29%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki