audio problems

[tincat]

i would be grateful for any thoughts on a situation w/my sound system which has me somewhat perplexed as to where to start. two of my receivers have begun to make loud scratchy and popping noises through all of three pairs of speakers. this is independent of volume or source and none of the other controls seem to influence the occurence. rain outside seems to bring this on(lightening doesn't appear to be involved). both units operate out of the same receptacle which seems to be ok. this noise will continue for a few seconds after the units are turned off and is intermittent w/no apparent connection to other devices. any ideas would be appreciated. thanx.

[Mooly]

A very big clue is you saying the noise carries on after switching off. That means the unit is running for a few seconds while the PSU capacitors discharge. I would try something else... and two receivers doing the same is a bit of a coincidence, bit too much really.

When it starts making a noise turn the volume down and disconnect everyhing (inputs, antenna turntable, turntable ground lead etc) until you are left with just the receiver and speakers. Is it still making the noise ? Now don't switch off but pull the mains plug instead to fully isolate. Does it still make the noise for a few seconds as it discharges ?

[Andy5112405]

Are you using same interconnects for all the tests ?

Something "common".

[tincat]

thank you for your quick attentions. it is late(early) here and i am reading a very good book by Patrick O'Brian-'The Yellow Admiral', but i must retire soon or just stay up for the day. however, i should add to my initial post some details. one recever powers a pair of jbl's, or, alternatively, a pair of wharfedales. the other has a separate pair of wharfedales. the first unit began the described behavior a couple of months ago and i switched to the second unit(both were used according to my preference of the moment), which then began the behavior a couple of weeks ago. the noise is unaffected by any alteration in any control, and can be very loud at zero volume on the pot. it seems random as well. isolation is a good idea and i will remove all inputs, though the noise is there even when all sources are unpowered. a quick thing i'm going to try when i can find a suitable extension, is to pluig the units into a different circuit out of the main power box. first, however, i think i will put down the book and get some sleep. will be back later and thanx.

[AndrewT]

possibly a broken solder joint in an interconnect. The stranded wire often breaks just as it exits the solder.