"Gareth Magennis" wrote in message
news

"Meat Plow" wrote in message
...
On Tue, 25 Nov 2008 18:54:01 -0000, "Gareth Magennis"
wrote:

IIRC, the C-Audio RA series commonly used BUZ Mosfets, both T03 and
T0247,
which are still easily available.

http://uk.farnell.com/jsp/search/bro...estid=48642 0



Gareth.




Good to know when the old J50's and K135's decide to check out.


Well, I didn't say the BUZ were replacements for those, but C-audio did
use a selection of different devices throughout the years they were in
production.

Some of the amps were rather prone to RF oscillations, burning out their
Zobel networks - attributed to various things like heatsink/ground
bonding or layout design, depending on who you talked to and what opinion
they had, or how much bull**** they liked to talk.

I replaced quite a few BUZ's, and they were expensive back then, about the
same as Farnell charge now. Can't remember changing many, if any,
reservoir capacitors though.




Gareth.



Oh, and the worst problem they suffered from was (allegedly) smoke fluid (in
club installs) being deposited on the PCB behind the fan intake. This would
eventually corrode lots of fine tracks running along the board, the most
common victim being part of the Protect/Speaker Relay circuit, so the amp
would stay in Protect forever.

Annoyingly, the corrosive substance would creep under the Speaker relays and
eat the tracks under them as well, so repairing these amps properly was
either very time consuming and expensive, or just plain uneconomical.

And, the 47 ohm 10 Watt ceramic Soft Start resistors would very often need
replacing.


These had their fair share of design problems, that's for sure.




Gareth.