[ARC5] Circuit Help Needed

[Kenneth G. Gordon]

On 11 Feb 2017 at 1:41, Rich Post wrote:

> Check out the Neustadt patent for that circuit.  Here's the schematic link. It's almost identical.
> 
> <https://patentimages.storage.googleapis.com/pages/US2443541-1.png >

Wel, not quite: Mark's circuit uses the 6SL7 connected in cascode with grid of one triode 
being connected to the plate of the other. The circuit I found in the Radiotron Designers 
Handbook follows Marks very closely. The only real difference is that the RDH uses a 6AS7 
pass tube.

> 
> From 700 to 250 is a major drop.

Yes. NOT good in my opinion. The input voltage for 250 V regulated output should probably 
be not more than 350 V at most.

>  The parallel 6Y6 pass tubes have to eat the remainder at that 
> output current.

Yes. However, if I am reading his schematic correctly, his pass tubes are 6V6s, not 6Y6s.

>   That's a lot like the linear supplies such as Astron where the pass transistors heat 
> up the difference.  A good regulated power supply limits the load on the pass elements by 
> arranging for the loaded dynamic voltage input to be closer to the output voltage.at maximum 
> current.  My big Kepco variable regulated supply actually uses a Variac in tandem with the variable 
> electronic control to keep the pass tubes happy by limiting that voltage difference.  Here's some 
> info on the Kepco.
> <http://boatanchorpix.x10host.com/Kepco605.htm>

Very interesting, Rich. Neat supply and even better job you did on it. :-)

Ken

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