When I hit a certain a certain frequency, it is followed by a distorted sound. Also certain notes have a vibrato like sound. I have eliminated all possibilities but the amp. I am wondering if it may be the filter caps or if anyone has any ideas. Thanks.
SWR SM 900 intermittent noises
Jul 23, 2006
2 Replies
I think I am correct in that this amp has a tube (valve) front end ?? If so, the tubes themselves would be my next suspicion, as such resonances can occur as a result of loose electrode structures. Is the problem affected by how loud the unit is turned up ? If so, could be a power supply problem. This amp has pretty meaty output stages, and poor power supply regulation could lead to problems with the front end. I think that the next place I might be going after that, is to try to set up the problem with a signal generator. It should then be fairly easy to track it down with a 'scope.
Arfa
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