random soundcard noise

[dr bu]

when i get rich i will change my setup, and buy better soundcards but at the moment im not and this is an annoying problem. ive got 2 400 mhz pismos and 2 G4s, 400 mhz sawtooth.
all but one G4 (os9.1 on this one; 9.04 or 9.2.2 on the others) have this problem which occurs very much at random. i use the original soundcard on all of these. if something is plugged in from an external source or not does not matter. the "noise floor" (if that is the correct term) now bounces between something like -45 and -35dB. often more on the right channel. cubase, pro tools, ableton... does not matter. im used to having a "bottom" more like -65dB. and then again sometimes, everything is cool.
are they all dying at the same time? or am i having extra terrestrial neighbors?

[supernova777]

which sound card u got ther dr bu;) 

[dr bu]

i dont know...how can i tell? the ones shipping.

[supernova777]

i dont know...how can i tell? the ones shipping.

oh u mean the built in sound ports?

[dr bu]

yep

[lokki]

try removing the power plug (if your battery still works). does it make a difference

[dr bu]

  no difference

[lokki]

hmm, you could record a short sample of the noise and upload it somewhere. maybe listening to it will bring some ideas...

[dr bu]

does it ring a bell?

[lokki]

kind of.

well it is no hum or static noise. to me it sounds like a capacitor dying shortly. would also explain why it's not all the time. does leave it on for a while improve the situation?

[dr bu]

a couple of hours now. dont think so. dying capacitor in the soundcard, do you think? ive taken pismos apart two times and the sound card is in the end of the line...
and i got two sparepart pismos.

[lokki]

well i don't know. i build guitar and bass effect pedals as a hobby and if i get a leaking capacitor in the audio path, it sounds like your recording...that's why i thought.

[lokki]

what do you mean by "in the end of the line"?

[dr bu]

...i mean, i order to reach (and change) the soundcard you have to take out almost everything else, and im still afraid to break something. i dont know... and i dont understand how i can get this problem on three computers at the same time! thanks anyway!

[lokki]

another possible solution would be a driver problem. something like automatic gain adjustment. but i think somebody here would know about that. and it would have happened all the time. not started recently.

[Graveyard]

I can't run the audio file on my iPad right now, but i'll listen to it when i get home. From your description, it sounds like the power management or something like that, turns off the sound chip after a while. I get something that i can't describe as anything else but background noise, whenever i use my amplifier and don't touch the Mac for a few minutes. I have quality cables and the whole sound system is shielded so it has nothing to do with the amplifier.

[DieHard]

I have 4 milk crates full of pismo parts... if you guys need anything... then message me... I can give some stuff away of charge very little... you have to pay shipping