Mains 120v ac supply rectified to feed 150vdc + supply to the resistor volt
drop > speed up circuit is necessary to achieve the HC-1 or RJ-1A <2mS
switch times good fo 35wpm, with no relay noise.
120 - 150 vdc is necessary to supply the circuit. Using 12v to 26v supply
or the available L4B 27 vdc relay supply is a waste of time and too slow.
120vdc is the normal relay supply in the sb-220 (conv to FWB rectifier
recommended) so is readily available for this circuit. Radj is varied to
suit supply vdc level.
-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Adrian
Sent: Friday, 8 June 2012 6:46 AM
To: [hidden email] Subject: Re: [Elecraft] K3 & L4B
QSK is well worth implementing, I did this with my sb-220, which is a very
similar 3-500z based amp. See;