phono preamp crackling

I would start by disconnecting all inter-connects to the int. amp except the balanced phono pre, then check. If problem is still persistent I would then start checking tubes.
Finding unwanted sounds is a process of elimination.

Your suggestion that it was fine until warmed up leads me to think it is probably a problem in the tubes.

Is there any effect when you touch the controls on the preamp? Or is the crackling independent of that?

as noted above, i do not have tubes in my system, ergo tubes are not the problem.

i don't notice problems when i touch the controls of the preamp--i think the crackling is independent of that, so the preamp is likely not the problem. on the other hand, the preamp may be very sensitive to static. i can still get crackling when i've turned the TT motor off and taken the arm off the lp.

i ordered an ionoclast today and it should be here by the end of the week. after i use it, i'll post on how well it worked. in the meantime, if anyone has other ideas please let me know.

thanks.

Although a defective phono stage is certainly a possibility (perhaps a marginal capacitor), it sounds to me like a good possibility would be that you are picking up rfi/emi (radio frequency interference/electromagnetic interference) from a fluorescent light fixture, a dimmer switch, or some other device which (like those) can generate significant rfi/emi.

Aside from turning off any such devices which may be nearby, what you could do that might be helpful is to take a portable transistor am radio, tune it to an unused frequency near the bottom of the band (near 540kHz), and during times that you hear crackling from the audio system see if the radio picks up corresponding crackling static-like noises. If so, you may be able to zero in on the source of the rfi/emi by walking around with the radio and noting where the volume of the crackling becomes loudest.

HTH,
-- Al

1. Make sure your rca females are clean of all oxides.
2. Ensure the IC's are gripping well. I was "sure" I had good IC's / connections and still had perplexing problems like yours until I got the outer casings of my rca's compressed a little (they had expanded just enough from being swapped around multiple times). Be carefull not to crack this tender area of the rca when compressing. Take note of the location of the plug casing slits and compress to close in these gaps a bit.

The above costs nothing: UNLESS you break a plug!
Good luck