phono preamp crackling

Photon46
GCPH has 40dB RCA and 46dB when using XLR for it's low (MM) gain setting --- and of course 47k loading not to forget.
Then you can use the 'volume knob' for further adjustment. NO WAY will you overload ANY functioning Line-Pre-Amp with a 3.6mV cart that way - rather the opposite would be the case since ~ 4.7mV be pretty much centre spec. for the GCPH.
Greetings,

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