[Amps] Amplifier Vs Plate Modulated

Roger (K8RI) k8ri at rogerhalstead.com
Thu Nov 26 01:27:20 EST 2015


I've posted the following on two group. They are not cross posted. 
Please do not cross post answers.  If you must post to both groups, 
please cut and past rather than cross posting.  Thanks!

OK, I understand, there's less iron in an amp Vs plate modulation, but 
how about a low level carrier driving a legal limit, plate modulated 
stage Vs a low level AM signal into a linear amp?.  Which is 
preferable?  Not many commercial ham amps can stand up, to long winded, 
AM transmissions and from my experience most AMers tend to be long 
winded, me included.  I talk like I write<:-) However Plate modulated, 
or linear amp, the power out limit is the same. With the new power 
limitations, AM appears to be the only loser,

So, what is the advantages and disadvantages for each.  Yes, I 
understand that many of today's rigs will run a nice clean  AM signal of 
relatively low amplitude (25 to 75 watts, bearing in mind that the 
dissipation in class A is driving the amp right to its limit.

I haven't run AM since the old plate modulated days. OTOH, I do run the 
5000MP in class A to drive a Tetrode to the legal limit.  The 5000MP amp 
only gets warm when run this way.  It gets hot if I reduce the drive.  
Class A runs the maximum dissipation with no signal input to the final.

Thoughts?

73

Roger (K8RI)

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