Arfa Daily wrote:
"Meat Plow" wrote in message
...
On Sat, 08 Aug 2009 16:38:30 +0100, Ron
wrote:

N_Cook wrote:
Meat Plow wrote in message
...
On Sat, 8 Aug 2009 07:41:16 +0100, "N_Cook" wrote:

Didn't think when initially checking out, but what is the "group"
slider
function,? no www user manual found.
Anyone any schematics for it ? (ps no emails to whatever this posting
apparently throughs up)
One channel clipping, then dropping out totally after a time, first
problem
in preamp, imbalanced gain, second unknown pa or prea. At least
possible
to
swap the pa channels over it would seem , to resolve to pa or prea ,
if
nothing actually found.
Also what governs the fan startup, comes on at power up for 2 seconds
(presumably normal) switches off and comes on whan heated up but
nothing
obviously separate from the amp/s for temp monitoring or total/channel
cutout, ie no relays, so some sort of gain control coming into play to
kill
the channel.

A group slider may refer to the aux buss group. Don't know how the fan
is governed but I'll assume it has infinite control like my
Studiomaster 700D amp. That probably gets its feedback from a sink
monted sensor, unknown where it is driven from.

I've never seen that before, a TO220 device trackside under each pa pcb,
thermally touching the heatsink. Only 2 pins used, the B-E junction,
with 2
isolated traces to the umbilical ribbon the carries the low voltage
rails
and signal i/p. I wonder what is special in the 2SD1763A used for that
purpose.


You need to be talking to Graham Stevenson (Eeyore) I think he designed
it.

Ron
Yeah don't talk to us lowly nincompoops about something someone else
designed.

Where's Graham gone lately ? Used to enjoy some of his design insights, and
also his tendency to suddenly fly off the handle occasionally !! :-)

C'mon Graham - bet you're still lurking - we all luv ya really ...

Arfa


Come to think of it, I havent seen him online lately (we sometimes have
a yatter in MSN) or in the pro.live-sound group. Hope he`s ok.

Ron