Hi,
My first post here, but I have got many great tips from here over the years and fixed up my own TSL100 Head from this Forum.
Currently I am fixing up a TSL122 for a friend that somebody had spilled a drink into while he was doing a bar gig, and I am seeing a strange issue. There is noise / crackling / popping on the Clean Channel only (with or without an instrument plugged in, doesn’t affect the amount of noise), switch to any drive channels and they are nice and quite. The only control on the clean channel that affects the noise is the volume pot, turns the noise up and down. Reverb does not affect the noise ether.
First off the Power Amp Section had some issues, these are all fixed now and there is no issues in the power amp section anymore. I have tried known good valves in the pre-amp section and have verified this issue remains with known good valves. I have removed V1, V2 and V3, and plugged straight into the effects return in the clean channel and the noise is gone. Placing valves back in to the pre-amp section 1 by 1, backwards from V3, the noise starts when V2 is inserted. Coupling caps C15 and C23 were replaced, and the board was put back in, everything was fine. The next day the noise is back, re seated all connectors and the noise is gone. Again, next day the noise is back.
If i turn on the amp and leave it on, the noise gets gradually quieter until it is gone, this can take about half an hour or an hour roughly if I remember correctly from the other day.
Once the noise goes away the amp sounds great, until it is left powered off for a while and then the issue returns.
Has anyone seen a similar issue to this? Any insight would be greatly appreciated. I am aware of the old PCB issue, that caused problems after being powered up a while with bias etc. , but this issue is isolated to the Clean Channel only and seems to get better after the amp has been left on a while. Thanks in advance for any suggestions
My first post here, but I have got many great tips from here over the years and fixed up my own TSL100 Head from this Forum.
Currently I am fixing up a TSL122 for a friend that somebody had spilled a drink into while he was doing a bar gig, and I am seeing a strange issue. There is noise / crackling / popping on the Clean Channel only (with or without an instrument plugged in, doesn’t affect the amount of noise), switch to any drive channels and they are nice and quite. The only control on the clean channel that affects the noise is the volume pot, turns the noise up and down. Reverb does not affect the noise ether.
First off the Power Amp Section had some issues, these are all fixed now and there is no issues in the power amp section anymore. I have tried known good valves in the pre-amp section and have verified this issue remains with known good valves. I have removed V1, V2 and V3, and plugged straight into the effects return in the clean channel and the noise is gone. Placing valves back in to the pre-amp section 1 by 1, backwards from V3, the noise starts when V2 is inserted. Coupling caps C15 and C23 were replaced, and the board was put back in, everything was fine. The next day the noise is back, re seated all connectors and the noise is gone. Again, next day the noise is back.
If i turn on the amp and leave it on, the noise gets gradually quieter until it is gone, this can take about half an hour or an hour roughly if I remember correctly from the other day.
Once the noise goes away the amp sounds great, until it is left powered off for a while and then the issue returns.
Has anyone seen a similar issue to this? Any insight would be greatly appreciated. I am aware of the old PCB issue, that caused problems after being powered up a while with bias etc. , but this issue is isolated to the Clean Channel only and seems to get better after the amp has been left on a while. Thanks in advance for any suggestions
