[Amps] Need for bias switch (CW/SSB)

[Jim Thomson]

Date: Mon, 11 Jan 2016 10:16:58 -0800
From: "Charlie" <charlie at drhabekost.com>
To: <amps at contesting.com>
Subject: [Amps] Need for bias switch (CW/SSB)
Folks-

I am putting a 8877 amp together. I was wondering why  some amps have a
"CW/SSB" switch.
Assuming the power supply can handle cw key down, other than higher
efficiency, what other reason could there be for this switch?

Thanks!

Charlie N6CFH

##  For  CW  use, there  is no need to use high amounts of idle current..on a gg triode amp. 
10-20 ma is ample for cw use.    which will require more  bias V... hence the switch.    Just use 
a string of  1N5408s  or  6A10s.... like  14-18 of em. 

## back in the old days the  cw  /ssb switch changed the B+.  This was for the  1 kw  /2 kw pep
rules, when amps rated in input power.    for low power 600w  output  cw  /ssb,  eff is btter when using 
a lower  B+.   Then the plate load Z stays  the same. 

Jim    VE7Rf