Re: Marshall 1987XL (plexi re-issue) problems...

In article <UJ1ig.137211$F_3.42344@xxxxxxxxxxxxxxxxxxxxxxxxxx>,
"Stephen Cowell" <scowell@xxxxxxxxxxxxx> wrote:

"Walter Campbell" <waltc@xxxxxxxxxxxxxxxxx> wrote in message
news:waltc-E1F397.15132408062006@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Got one of these in the shop today because:

- doesn't ever really turn off. If you're in the high input of either
channel with the vol pot all the way off you still get a little sound
from the guitar through to the speaker

- both channels, especially the "bright" (high treble) channels come on
FAST. I mean there's little sound then bam, you go from "almost off"
(see above <G>) to what sounds like 4 or 5 on the dial.

Either cheap, or wrong, pots? Check the linearity
of the pots... they should be *non*-linear, audio
taper.

If the vol pot's ground is no good you'd see
something like this... check the pot buss gnd.

Also, you're kinda describing the effect of the
vol pot bypass cap...like a 'bright' cap, but
in all the time. If the circuit has one of these,
check the value... if it was very large, it could
cause the symptoms you describe. GL!
__
Steve
.

There is a 4n7 cap in the "Bright Treble" (second channel) circuit
that's on all the time, but the owner likes that part<g>!, it's the
on/off volume knob operation and "way loud by the time it overdrives"
character that he wants to change.

Sounds like that's the general character of the amp. I'm inclined to
suggest that he sell the amp and get something more appropriate to his
tastes, hmmmm, we'll see....

Thanks! (to all, I'll check out the metroamp site too).

Walt Campbell
Campbell Sound
http://www.campbellsound.com/
.

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