Op 26-2-2011 0:43, Bernhard Kuemel schreef:
On 02/25/2011 07:18 PM, FF wrote:
Here (http://www.mikrocontroller.net/topic/144407) is a discussion in
German about the same amplifier. Schematics and board layouts are
included in that thread.
The schematics are from a PA-8000, so the fuses may well be different.
Hmm, the drawing number (Zeichnungsnummer) is 'PA 5/8000 ...'. So maybe
the fuses are the same.
(side note: in his case R65 on the 4th page of the schematic was blown,
pls. note how Mc Crypt designed a 14V power supply from the 65V rail
voltage......)
Ok, I think I understand the circuit. I don't understand enough about
electronics, though, to understand your point.
Bernhard
On the fuse: I *think* it's safe to try the "next lower value" fuse for
the 5000, assuming the fuse in the drawing is for the 8000. However,
YMMV ;-)
On that 14V power supply: that design is rather crude, there's a lot of
dissipation in those power resistors. There are far more elegant ways to
design a 14V power supply for these LED's (e.g. separate transformer
windings, small SMPS etc).
According to the thread I mentioned, apparently there are quite a few
problems with this amplifier(s), and they are in no way suitable for
*real* PA work. BTW: in Europe they sell for 115 EURO = around 90 USD!
Pardon my English, I'm Dutch ;-)
FF