[Amps] interesting statement in Dishtronix

[Leigh Turner]

Not Freescale parts Jerry, but the capable ST Micro SD2943 RF MOSFETs that
typically yield circa 400 Watts per device. I'm using four devices in
parallel push-pull per nominal 1200 Watt module; two 1200 Watt modules with
their outputs combined, so total of 8 FETS to conservatively produce the
nominal 2400 Watts. The maximum achievable Po is limited by the switch-mode
supply's Ampere capability!

Each module has the 4 device flanges on a 13mm x 220 x 300mm copper slab
heat spreader that bolts to a large aluminum finned heatsink that's cooled
with a whisper quiet low velocity 300mm long tangential cross-flow blower. I
think many commercial QRO S.S. amps skimp on the important thermal design
aspects, as well as the control and protection circuitry.

Yes indeed, I like my trusty old Kenwood TL922 amp with its pair of 3-500Z
instant-on thoriated tungsten filament tubes for that very same reason!

Cheers,

Leigh
VK5KLT

-----Original Message-----
From: Jerome Kaidor [mailto:jerry at tr4.tr2.com] 
Sent: Tuesday, 20 November 2012 9:32 AM
To: Leigh Turner
Cc: amps at contesting.com
Subject: Re: [Amps] interesting statement in Dishtronix

Leigh Turner wrote:
> 
> Turning on a tube amp and waiting for the heaters to warm up seems like an
> inordinate amount of time when you hear that rare DX station calling CQ; 
> the solid-state amp being instantly ready for service!

*** That's one of the main advantages of an old-fashioned 811A linear like
the 30L-1.  Flip the switch, and you have full power about a second later.

Running an 'L1 on RTTY seems abusive though.   That's why I obtained my
Alpha 78.

A full-legal-limit SS amp would definitely be cool.  Are you using the
Freescale parts?

                         - Jerry, KF6VB