[AMRadio] Any amplifier suggestions?


Todd Carpenter n9ysq at yahoo.com
Mon Oct 5 13:07:28 EDT 2009


I have a heath dx 60 and vfo to drive it with. Just have to find someone to help me fix the dx60. I am not sure which is better, but no tune would be a plus. I have 6 of the  1625 tubes as well. I also have a 1940 handbook with a single tube 4-400 amp in it. But i am looking for maximum am output.

-----Original Message-----
From: John Coleman <jc at pctechref.com>
Sent: Monday, October 05, 2009 10:26 AM
To: 'Discussion of AM Radio in the Amateur Service' <amradio at mailman.qth.net>
Subject: Re: [AMRadio] Any amplifier suggestions?

Todd, 
Typically the linear amp will be the fewer parts and expense but with less
output than a full plate modulated class C rig per a given tube.  One of the
simplest tetrode linear systems is to put a 50 ohm load resistor right on
the grid of a big jug like a 4-1000 or a pair of 4-400s and use a zener to
bias the cathode circuit or fil return. It will also require a screen
supply.  The idea in all of this is that if the grid is loaded with a 50 ohm
dummy load, then it will not require tuning.  The small amount of input
capacitance will be negligible on the lower freq bands.  And it should not
require neutralization.  

OTH, If you are going linear with a triode or triode connected tetrodes then
you will want to go to a grounded grid linear.  No screen supply, no
neutralization, but does require more drive and/or may require drive tuning


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