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Help: Unidentified high-pitch sound

Hello---I'm hoping someone can help me identify the possible source of a intermittant high-pitch sound coming from my left speaker. So first of all, here's my system:
-VPI TT
-Modwright SWL 9.0 AE preamp
-Bel Canto REF500s amp
-Marantz 8006 CDP/streamer
-Dynaudio Special 40s
-WyWires ICs

My system is only about a year old old and up until a week ago, everything has been just fine---beautiful music. I usually hear the tubes warming up for the first couple of mins with a little 'ping' sound. But then I noticed a slight but audible high-pitched sound coming from my left speaker---nothing on the right. I had been listening to the streamer when this happened. So I switched the sources on the preamp and still noticed it no matter what source I picked. But sometimes it did disappear while I was switching the source. I don't notice it when the music is playing---but when the song stops, I hear it. Then, a couple days ago, I was turning off my system and noticed it disappeared when I turned off the Bel Canto. So is the source the amp or the preamp or something else? Thanks so much for any advice.
bluorion
mijostyn's avatar
mijostyn
8,570 posts
 
Hi bluorion, It could be anything but the speaker. So now you have to play detective. Start at your sources buy switching right and left channels.. one at a time. The unit that swaps sides is the problem. If the sound does not change sides then switch channels on the preamps inputs one source at a time testing all the ICs. Then on the preamp's outputs. If the sound changes sides you have a preamp problem. If not then switch sides on the amp's inputs. If the sound switches side you have an IC problem, if not now swap channels at the amps output. If the sound changes sides you have an amp problem. If none of this works (which it will) you have a big headache. I suspect it is either the preamp or the amp.

Good luck,
Mike
uberwaltz's avatar
uberwaltz
13,381 posts
 
My first point of suspicion would be the Modwright preamp with a tube going bad.
I would start there, swap the main pre output L & R to the power amp and see if it moves with it.
If so it is possible a new pair of tubes are the order of the day.

Good luck and stay safe
uberwaltz's avatar
uberwaltz
13,381 posts
 
If it does move with the preamp output swap you could then go further.
Open up the preamp( powered down of course) and swap the tubes themselves L and R.
While in there you might possibly find one tube was loose in its socket.
Anything is possible but I would definitely start at the Modwright if it was myself.
Good luck.
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