Mine is also a very early unit as it has FD09 printed on the second floor of
the power supply. According to Dennis, the guru of Henry amps, Faye Danza made
all the power supplies and she numbered each with her initials and the number.
mine has the 470 ohm resistor in series with the 500 ohm adjustment pot. I am
going to increase the value of R16 to 1000 to 1500 ohms to see if I can
increase the amount of current going thru the meter. With the 470 ohm resistor
I am seeing only 190ma when it should read 500ma using the setup procedure that
appears on page 16 of the manual. Other than that, the amp works great with
the 3CX1200D7 and the auto tune input circuit. It's really great having an
instant-on amp! I am seeing 2000W out with 120 watts of drive. This produces
200ma of grid current, which I am told will not hurt the tube at all.
73 Bob W6TR
----- Original Message -----
Sent: Saturday, June 24, 2006 8:30 AM
Subject: Re: [Amps] Henry 4K Shunt Resistor
My manual says R16 should be 470 ohms at 1 watt. I looked in the amp and it
is the resistor in my amp. Mine is one of the first made according to the guy I
got it from. Maybe there was a change in later models? Good luck.
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