Most likely excessive gain in the system.
The GCPH preamp he has is solid state. Tubes aren' t the culprit here. I'm not sure you're telling us enough to be sure of the problem. Are you saying that if you move the phono stage different distances from the turntable, that change in distance results in a repeatable, consistent variance in the level and/or frequency of occurrence of the crackling noise? Just trying to determine if the distance/placement is really the problem here. Also, what are you using for phono interconnects? I've had really annoying noise problems from unshielded phono cables. Does moving the phono interconnect result in any noises?
He has a PS Audio phono stage that is solid state, not tube. I would suspect maybe a high level of static electricity build-up somewhere around his system. Try a product called "Anti-Shock". It is a spray that reduces static. Spray on carpet and/or rugs that are close to the equipment. You could also try a air purifier/ion device.
OK I'm a dump shit with a strong preferences! :-)
That said, have you tried disconnecting the IC's from your TT (cartridge) to the phono stage? If not try that, leaving the IC's to the pre-amp in place and seeif that changes anything. The phono stage might be fine but the IC's from the TT/cartridge to the phono stage could be the ones picking up stray magnetic fields, as opposed to the IC's from the phono stage to the pre-amp.
first, thank you for the replies.
to photon46, yes it seemed that when i placed the phono preamp in different locations relative to the TT that the freq of the crackling noises would change. i'm no sure now however, read on.
to audiofeil, if it is excessive gain in the system, what am i to do? i am new at this.
i just played about 1.5 hours of vinyl. for three sides worth of music i had no problems. then the crackling started. i moved the phono interconnects back and forth but that didn't produce any effects.
i put back on the first record, i.e. the one where i was having no crackling, but now there is crackling, so it's not the records.
maybe it is a build-up of static electricity. however, i have no carpet nearby (wood floors). also, the humidity here is 65% today which is enough to deter static electricity, though perhaps not enough when playing vinyl. i don't have a zerostat gun so i haven't tried that. another $100!
also, i have not been using the mat that comes with the TT, i've been placing the record directly on the platter with no mat. seems like this would make for less static, but i really don't know. i guess i could try the mat, but then i have to readjust the tonearm height.
as for the IC's from the TT to phono preamp, i assume they are shielded. the ic's came with the TT (marantz 15s1). the owners manual didn't say one way or the other about shielding.
mapleshade makes a similar zerostat type device called the ionoclast for $40.00. i live in the deep south where humidity is often 70%+ and i have wood laminate floors as well. i still have issues with static when playing records. static is created by friction (the needle and your lp). i've heard that an rcm helps to reduce static, but i'm low on funds after some new upgrades so i can't comment directly on this.
Assuming you're using the stock Clearaudio cartridge the Marantz ships with, you're working with a 3.6 mv cartridge signal. That's pretty middle of the pack, nothing unusual there. Not sure exactly what the GCPH's lowest gain setting is, but I'd make sure you're using it. (That gain block is adjusted with the left blue knob on the back of the chassis.) I wouldn't think a 3.6 mv signal should overload any competently designed MM phono stage. Also make sure the output gain of the GCPH isn't set too high also. Don't want to overload the input on your Cambridge either.
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.
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.
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.
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.
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!
i promised i'd post a response once i figured out what was going on. i'm fairly sure i know where the cause of the crackling lies.
first, some have speculated that i have noise in or around my system. there are no fluorescent lights nearby (at least that are on), and i have two dedicated lines from my breaker box to a quad receptacle to power my hi fi equipment. so i don't think that is the problem. also, i tried the suggestion from almarg, and set my tuner to an am station but did not hear any crackling through the tuner.
i think the problem is in the phono stage itself. the only way i can get the crackling to stop is by tapping on the back of the gcph. the crackling stops completely. note that i have made sure all the connections in and out of the gcph are secure. i'm using balanced connections out, the grounds from my TT are very tightly secured, as are the rca's from the TT. again, a couple taps towards the back of the phono stage and all crackling is gone, at least for awhile. i figure there is something loose in the phono stage.
if you have any other thoughts let me know and thanks again for all the suggestions.