| Author |
Message |
Guest
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 Posted:
Sat Oct 29, 2005 1:27 am Post subject:
Channel noise in Scott 200c amp |
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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
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Jon Yaeger
Guest
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| Posted:
Sat Oct 29, 2005 4:42 am Post subject:
Re: Channel noise in Scott 200c amp |
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in article 1130531236.821125.279290@z14g2000cwz.googlegroups.com,
kaczmar2@gmail.com at kaczmar2@gmail.com wrote on 10/28/05 4:27 PM:
| Quote: | 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 |
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west
Guest
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| Posted:
Sat Oct 29, 2005 4:42 am Post subject:
Re: Channel noise in Scott 200c amp |
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"Jon Yaeger" <jono_1@bellsouth.net> wrote in message
news:BF883F80.3D301%jono_1@bellsouth.net...
| Quote: | in article 1130531236.821125.279290@z14g2000cwz.googlegroups.com,
kaczmar2@gmail.com at kaczmar2@gmail.com 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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Mike Coatham
Guest
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| Posted:
Sun Oct 30, 2005 1:57 pm Post subject:
Re: Channel noise in Scott 200c amp |
|
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<kaczmar2@gmail.com> wrote in message
news:1130531236.821125.279290@z14g2000cwz.googlegroups.com...
| Quote: | 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
|
I'd try swapping the output tubes channel to channel for starters. If the
noise stays in the faulty channel then the Output tubes are blameless. If
however the noise swaps over with the tubes then the problem is obviously
with one or both of the output tubes ( I'm unfamiliar with this model but
assume it has two output tubes per channel?).
Repeat the process with the other tubes(one at a time) to see if the fault
swaps with the tubes. If it doesn't, then at least you can cross them off
the hit list.
Anyway, try this and report back. |
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