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

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Feedback on Thorsten's legacy "universal dht" amp
Feedback on Thorsten's legacy "universal dht" amp
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
Thread Tools Search this Thread
Old 28th July 2006, 05:34 AM   #1
jarthel is offline jarthel  Australia
diyAudio Member
Join Date: Jan 2002
Location: somewhere in Australia
Default feedback on Thorsten's legacy "universal dht" amp

I've search here and in AA and can't seen to find much discussion on this amp.

thanks for the replies.

ps. maybe I was using the wrong search criteria so I wasn't getting good search results.
  Reply With Quote
Old 28th July 2006, 11:09 AM   #2
JimW is offline JimW  United States
diyAudio Member
Join Date: Oct 2004
Default legacy

I am guessing you have read Thorsten's article at Thunderstone audio. I have a pair of these, at least a variation. I used the el84 driver. I departed from the Legacy as descibed by TL in a couple of places. I used a cathode resistor (1760 mills 12w) and bypass cap (22u polypro) on each leg of the 300b filament circuit, which is how I think the original Verdier design was implemented, although I added a pair of WE (ultra path) caps (6u GE motor run caps) from each side of the filament to b+ tap of OT. You might note that this implementaion results in different bias on each side of the output tube due to the dc filament supply. I am not sure if it will affect tube longevity, western electric allowed for use of dc on the filaments per their data sheets. I have the filaments polarized oppsite each other on the amps, and rotate the tubes amp to amp periodically. In addition, my psu is nothing special, a clc (small tuning cap, choke, and large cap for main b+, with additional rc for the driver stage. The driver stage needs a pretty smooth dc to avoid hum, so the extra rc stage. This was actually based on advise from TL, since I wasn't going to do the regulated supply thing. The hum level at the speaker terminal is low, about .6-.8mv. I will say these amps sound very good - easy to listen for hours without fatigue!
  Reply With Quote
Old 28th July 2006, 02:01 PM   #3
kstagger is offline kstagger  United States
diyAudio Member
kstagger's Avatar
Join Date: Dec 2003
Location: Grand Rapids
I made the amp using an SV83 driver and changed the bias on the 300B a bit too. I also used Electron One output transformers.

For the power supply, I used an outboard 200mA/500V HP Regulator. The filament supply was onboard and I used a pair of 5VAC Hammond transformers with a hum-pot. I ended up with a small bit of hum - sound was really nice - lots of snap - with plenty of detail and good treble extension. 8ws of power just wasn't enough when listening to AC/DC though!
  Reply With Quote


Feedback on Thorsten's legacy "universal dht" ampHide 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
"universal" P-P driver board Tubelab_com Tubes / Valves 43 6th February 2009 03:55 AM
Developing a "universal" tube power supply PCB Geek Tubes / Valves 42 15th August 2007 07:10 AM
Wanted: Hammond 125E or other "universal" output transformer Spasticteapot Swap Meet 2 13th July 2007 10:29 PM

New To Site? Need Help?

All times are GMT. The time now is 09:02 AM.

Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 16.67%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio