[AMPS] ultra linear circuit for audio

[nospam4me@juno.com]

Hi Colin, 
re your audio amp ultra linear comparison.
The common "ultra linear" audio circuits I have here, use a 
"second transformer tap" for the screen grid. That was the 
common (MacIntosh Tube Amp type) Ultra Linear circuit  
hook. Some of my Heathkit are similar in design.

The daf rf circuit is a different animal.  

:From: "Colin Lamb" <k7fm@teleport.com>
:A "regulated" screen voltage does not make a perfect linear amplifier.
:Examine the "Ultra-Linear" (also known as the Williamson) amplifier
design.
:A few of these audio  amplifiers were sold by Heath and others.  The
circuit
:necessarily uses a screen dropping resistor and could not use a screen
:regulator of any design.

:Yet very few were sold commercially.  Most people do not understand how
they
:work.  Yet, they work very well.  You will not see a screen voltage
:regulator circuit in any Ultra-Linear design.

All about cost, the hybrid tapped output transformers are expensive to 
produce. Audio transformer for Ultra Linear Operation are still sold.
Look 
for it to add a few db to the project cost. Ultra Linear Operation
(audio) is 
described in books sold through Glass Audio Magazine. A sister 
publication to Audio Amateur Mag.

:But, there are some who will stick their head in the sand and forever be
:convinced that things will not work because they saw or heard a bad
example.
:Colin  K7FM

It's more of a question of how well it works.  My neighbors Chevrolet 
Vega automobile still runs just fine. Lime green too... 

skipp

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