[Amps] Expert Amps 2K-FA: Any Opinions ?
Paul Christensen
w9ac at arrl.net
Wed Apr 25 06:57:49 PDT 2012
> I would also be concerned about cooling (and noise) with that much
dissipation in such a small box.
I have the 1K version of the SPE amp. Nice, compact and reliable design.
If the League's QST product review is to believed, IMD performance is
excellent for a solid-state design.
No contesting here but when using CW in say....a 2-3 minute exchange, the PA
deck becomes quite hot and the fans are running "full tilt," resulting in
what sounds like a jet engine. That, together with output power that
changes with PA deck temperature seems to be problematic with most
commercial solid-state amps. SPE does use a very well designed protection
system. In effect, a high-speed bus is created to kill bias to the PA
transistors when one of about a half-dozen faults occur.
I like the amp for its instant-on, compact design, but I would never use it
as a replacement for a good VT amp. I saw the 2K amp recently at the
Orlando hamfest and for folks wanting a solid-state amp, I think it's worth
considering. But if noise in the shack is bothersome issue, ask other
owners about noise level with varying duty-cycle at full output power.
I believe the 2K version has a vacuum relay option that adds several hundred
dollars to the purchase price. In my 1K, its T/R frame relays were way too
loud. I ended up modifying the amp's logic for use with an Ameritron QSK-5.
The interface between the two units is optically isolated and a schematic is
shown on my QRZ.com page. Much happier with this arrangement as it's fast,
silent, and no truncation of keyed elements.
Paul, W9AC
More information about the Amps
mailing list