[AMRadio] AM Amps

Gary Blau gblau at w3am.com
Wed Jan 12 00:02:31 EST 2005

Not sure I understand that answer.

If the amp can easily handle 1500W PEP, and if your audio is symmetrical
(a big if), then the dreaded 375W number is a safe place to start.  (I
can hear gaskets popping out there now...)  
If you have a PEP wattmeter, then adjust while looking at that for a max
of 1500W on highest voice peaks.  Make sure your negative modulation is

More importantly, tune up the linear with full drive.  Use a driver that
can deliver 100W or whatever the amp needs for 1500W PEP out, and tune
there.  (You might use your SS ricebox with a CW keyer sending dits to
keep the duty cycle low while tuning.)  Then leave it alone.  Connect
the Ranger and adjust the screen for that unmentionable number just to
start.  The amp tubes will be dissipating a lot of power, so be sure the
tubes can handle the dissipation at dead carrier (the worst case), as
described by Gary Schafer several posts ago.

Rock and roll.


Geoff wrote:
> Byron Lichtenwalner wrote:
> > If you had an amp rated at 1500 pep rated for Continuous Commercial
> > Service and were going to drive it with a Ranger, (with W3AM's
> > modification as an example) where would you set the carrier level with
> > no modulation?
> > Byron, W3WKR
> Where the 'scope showed that I had 90% negative modulation peaks.
> "Operating your AM rig without an Oscilloscope
> is like driving your car at night, without headlights"
> (Don Chester -K4KYV)
> 73 = Best Regards,
> -Geoff/W5OMR

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