[AMRadio] Amplifier to use with my DX-60
John E. Coleman (ARS WA5BXO)
wa5bxo2005 at pctechref.com
Thu Mar 16 22:09:50 EST 2006
I still say, forget the linear, and use less money to build a plate
modulator for the DX60. It will work better, sound better, cost less, and
heat the shack up less. As I recall the DX 60 has a 6146 in the final for
class C CW and puts out about 40-50 watts of carrier if it were plate
modulated it would do at least 200 watts PEP and sound great. There is a
number of different ways to do the modulator. A lot of guys just find and
old PA and a transformer to match to the final. Some build the modulator
output stages only, input XFMR tubes and modulation XFMR. Then they drive
it with a small microphone amp. That's more stuff to set around on the desk
but it works. There are a lot of self contained 25 and 50 watt modulator
circuits around and probably a lot of complete one piece store bought
modulators as well. As I recall, EICO had a pretty nice one that was to go
with the EICO model 720 but it was used on many different rigs as well as
being used as a driver for big modulators. A buddy of mine had an ECIO 720
and built a nice home brewed modulator for it using 1625s in AB1. It sounded
real good. I built one similar to it with less power output for my Knight
Kit T60. The T60 had the same control carrier AM that the DX60 does. What
a difference it made when it was plate modulated. Very little modification
is necessary in the DX60 to accommodate the external modulator.
John,
WA5BXO
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