wrote in message
...
On Mon, 16 May 2005 13:59:21 -0400, "Robert Morein"
wrote:



Then bass control is is great importance to you. You need a big amp on
the
bottom.

Indeed........


I don't recall - is the Andromeda a Class A design?

I believe it's Class A/B

Yes. The only caveat would be fan noise, which is slight, but meaningful
in
some installations. The P3000, P4000, 9300, and 9500/9505 series are
fanless, with external heatsinks.

Understood, so the technology remains consistent, however the pro amps
have fan cooling rather than heatsinks

No. The availability problems concern older MOSFETs, the Hitachi parts
that
were originally used. MOSFETs are currently in wide electronics use,
particularly for power switching. Modern parts are plentiful and cheap.
MOSFET amps are rugged. Supposedly, they can be shorted without damage.
However, spontaneous failures of the old Hitachi MOSFETs have been known
to
occur.

Would it be possible to "upgrade" my Andromeda with the current MOSFET
technology, or would everything get thrown out of whack, so-to-speak,
based on the original design parameters?


The newer MOSFETs have slightly different parameters, including Rdc, which
causes me to question whether any of them can be used as drop-in
replacements. It wouldn't burn up, but it probably wouldn't sound right
either. I assume Sander is looking at the spec sheets, so he may be able to
knowledgeably contradict me.

The other problem is that each set of P's have to be matched with each
other, as with each set of N's, or the load distributes poorly between them.
The old Hitachis were graded into three categories by Hafler; I don't know
whether manufacturing process has rendered this unnecessary with the new
ones.

But as the Andromeda is a "traditional" MOSFET design, you can get improved
bass control with a Transnova, or bipolar amp.