Re: Channel noise in Scott 200c amp


"Jon Yaeger" <jono_1@xxxxxxxxxxxxx> wrote in message
news:BF883F80.3D301%jono_1@xxxxxxxxxxxxxxxx
> in article 1130531236.821125.279290@xxxxxxxxxxxxxxxxxxxxxxxxxxxx,
> kaczmar2@xxxxxxxxx at kaczmar2@xxxxxxxxx wrote on 10/28/05 4:27 PM:
>
> > I have a Scott 299c amp that has been working great for the past few
> > years. Recently, I have been hearing noise in one of the channels
> > (right.) The noise is an intermittent hissing/crackling sound (not
> > too loud - low volume will drown it out.) This white noise does not
> > change if the volume is adjusted up or down.
> >
> > I am not very well versed in tube electronics (or electronics in
> > general) for that matter, so I really don't know what the culprit could
> > be or how to test for it. I suspect it could be the output tubes but I
> > really have no idea.
> >
> > On a related subject, is there a good book(s) out there that give a
> > nice practical overview of consumer tube/solid state electronics.
> >
> > Thanks,
> >
> > Christian
>
>
> Could be any number of things, such as a noisy plate resistor. First,
clean
> the tube sockets and check the tubes by substitution to eliminate them as
> possibilities.
>
> Good primers are by Morgan Jones (e.g. Valve Amplifiers) or Bruce
Rosenblitz
> (sp?). However, these authors cover more about design and operation than
> troubleshooting.
>
> There were many books written years ago dealing with troubleshooting tube
> circuits. Check your local library.
>
> Jon

I don't know what level you wish to pursue this hobby, but an inexpensive
scope will show you where the problem is. Do you have access to one? If you
don't, then realize that a stereo has redundant circuits, except for the
power supply, which is not you problem, because the PS is common to both
channels, etc., etc...

west


.

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