>
>Hi Rich,
>
>What's an "outout" control?
>
>The 1000MP has an output level control indeed. But I never trust just
>turning down the output level to prevent overdrive of 8874's, they pop way
>too easily...which is why I leave the resistive pad installed in the 374A's.
>It provides sufficient attenuation to make overdrive impossible, but still
>allows the amp to run ~1500W PEP output, which is all it's supposed to do.
>
>On many rigs the RF out control is too close to other controls and could be
>easily bumped into the "gee, I wonder what vaporized the grids in my $400
>8874's?" position.
>
Autopsy shows that the 8874 grid is not damaged by overdrive. The damage
is to the cathode's emissive coating - which flakes and shorts the grid.
/photo of flaked cathode in "Parasitics Revisited", Sept/Oct 1990
*QST*./
cheers, Steve
>
>> -----Original Message-----
>> From: 2 [SMTP:2@vc.net]
>> Sent: Monday, December 03, 2001 10:08 AM
>> To: Steve Katz; 'jbrown@luminet.net'; AMPS
>> Subject: RE: [AMPS] Alpha 374A
>>
>> >
>> >We use that combo among others at my contest station, K2XR (1000MP/374A)
>> and
>> >there's nothing to do to set it up except attach the coax from the rig to
>> >the amplifier...
>> >
>> >The 374A has untuned input and a large resistive swamping network at the
>> >input, I'd leave that in place for the 1000MP, to prevent overdrive.
>>
>> Does the 1000MP lack an RF outout control?
>>
>> - R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
>> end
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|