[Amps] Swan Mark 1

[Steve Katz]

> What is involved in replacing the 3-400 tubes in the
> Swan Mark 1 with 3-500ZG?
> 
> Anyone had experience with this amp?
	  
	::I converted a Mark 1 to 3-500Z's, and same goes for an old Swan 6m
amplifier called a Mark-IV.  Did the same thing for both, e.g., relocated
the tube sockets down below the chassis using aluminum standoffs, and added
~+5V cathode bias using a 50W (or maybe it was 100W?) stud zener mounted in
a new hole in the chassis.  Not a difficult conversion.  But I wouldn't
recommend using the 3-500Z's at "zero bias" as the 3-400Z's were used --
seems to me there were many published articles on this back ~1970 or so when
the 3-400's were being phased out in favor of the 3-500's.

	-WB2WIK/6

> 73,
> Bill Smith KO4NR
> 
> =====
> Bill Smith KO4NR
> 
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