Posted by Howard [ 203.51.242.87 ] on March 30, 2005 at 07:07:10:
Dear SET forum,
I have been seriously considering three valve amp designs over the past two weeks.
The Darling,
http://www.diyparadise.com/Darling.html
This is a very well liked, simple straightforward circuit, cheap parts (Great sound) but low power.
A KT88 SE as suggested recently and described here
http://pmillett.addr.com/elinear.htm
and an Australian design known as The Tweaker. (No web page available) The design like the two above is relatively simple. It is a two stage using a 6SL7 to drive one of the following;
KT88, a KT66, EL34 or a 6L6. The user simply tweaks the bias to suit the chosen output. (Each channel uses just 11 resistors and 3 caps)
The designer Earle Weston (Melbourne) (eBay alias ehtcom) also winds his own transformers and is able to supply all parts as required. The power output will vary between 9.5-14W in pentode mode. (Approx half this in triode mode)
With so much local support, design and parts supply I have decided to build a dual mono version of the Tweaker.
I would like to display the circuit diagram but I should ask the owner first. I will be getting the power supply parts made up over the next few weeks.
I will probably be pestering this forum with lots of questions when I start putting it all together. I hope you are all patient.
Thanks for all your great advice so far
Howard
http://www.eastmarinedrive.com
One of Earle's KT66 designs