[Amps] Commander II output circuit

[R.Measures]

•  It never ceases to amaze me how often amplifier experts seemingly do 
not read manufacturer's specification sheets.  To estimate 
grid-dissipation, multiply indicated grid-current by the RMS voltage at 
the cathode.  As I recall, the RMS potential at the cathode of a 3cx800A7 
is c. 50V.  Thus, 40mA of grid-I = c. 2 watts dissipation on the 5W-rated 
grid.  

cheerz, Eric

>Interesting,  Commander wants you to keep it under 40 ma and it has a 
>protection circuit that trips just over 40 ma.
>
>
>----- Original Message ----- 
>From: "R. Measures" <r at somis.org>
>To: "ERIC OLSON" <ericn7epd at msn.com>; " AMPS" <amps at contesting.com>
>Sent: Sunday, March 14, 2004 8:34 PM
>Subject: Re: [Amps] Commander II output circuit
>
>
>
>
>>Hello! I just purchased a used Commander II 2 meter amp and it runs high
>>grid current all the time.  About 30 ma at 10 watts drive and 40 ma at 20
>>watts drive.  I swapped the 3cx800 with a "good one" from a friend and it
>>does the same thing.  Checked for shorts and ground connections in the 
>>final
>>compartment but all OK.  Replaced the DC blocking doorknob cap and no
>>change.  The link coupling is very rigid and I doubt it would change much
>>from amp to amp or in transport.  Get about 450 watts out at 20 watts drive
>>and 250 watts out for 10 w drive so think the tube is OK.  Help!
>
>  30mA represents c. half of the rated grid dissipation.
>
>cheers,  Eric 
>