[hpsdr] munin design

[Mike Collins]

On 5/6/2013 7:27 PM, FRANCIS CARCIA wrote:
> Hi All,
> I have a question. Why does the Munin final feed DC into the 
> transformer CT. and also use a DC feed choke. I've never seen this 
> done before and wonder why. Frank WA1GFZ
>
Hi Frank,

The DC feed choke ( L8 ) is decoupled so is just a better filter on the 
DC to help on balance and IMD.

The interesting part to me is all the flexibility in the amp for 
fiddling....  The feedback transformer is somewhat unique too, in that 
the DC feed thru it and the output primary too.

Lots of places to experiment...  I want to try replacing L8 (and output 
caps) with an auto-transformer choke feeding the drains. Maybe removing 
the center tap ground on the output and/or feedback transformers; or 
decouple to ground with cap to maintain RF symmetry.  All of the 
transformers are conventional, so it will be easy to add/remove center 
taps, or tie/decouple to ground/power.

Lots of fun !!

73,  Mike Collins   KF4BQ

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