Roxy, "Hum" is formally defined as a persistent 60Hz or 120Hz noise. But on audiophile websites, I think the word is often used very nonspecifically to refer to almost any sort of unwanted noise, often of mixed frequencies. If you are now experiencing a 60Hz or 120Hz noise, in your latest post, then its cause may be entirely different from your earlier problem in origin. In other words it may not be due to RFI; it may instead be due to some sort of grounding problem or to any of many other causes. Since unplugging your flat screen TV cured the first problem, and since it recurred when you add in the Allnic head amp, this suggests there is some other source of RFI that can enter your signal path after being picked up either by the TV or the Allnic. The source could be airborne or via AC lines (RF can go anywhere), if it is not due to the TV or Allnic per se, which seems very possible. Since you are in an apartment building, that makes the source of RFI hard to pin down, because it could be coming from a neighboring apartment. This latest issue, slight "hum" when the needle touches the vinyl, was that part of the earlier syndrome? Or is this new? And is this true "hum"?
Has anybody never been able to solve a hum static problem with a phono pre amp?
I have had for years now a hum/static problem with my phono pre amp. I have not been able to listen to analog for too long a time. Let us just say for years. I have localized it to the phono pre amp when it is just attached to the pre amp and amps. Nothing to do with the head amp and turntable. I have tried 3 different models and it is the same problem. I have tried every single piece of info I have found on audiogon and the internet. Cheater plugs, giving it its own socket, grounding it to every piece of equipment, moving it away from system, moving router, making sure connectors are shielded... I have even had two turntable experts from the NY tri state metro area come over and they cannot figure it out. This was not the case when I got it initially. It was dead quiet. But I changed my setup from a Toshiba black box to a flat screen TV and that’s when the problem started. That’s how long it has been. But to be honest I had that black box long after people had switched to flat screens. TV wasn’t that important to me. I sometimes think at the same time somebody in my apartment building or surrounding dense city area put up an antenna and it is causing interference about which I can do nothing. As I said I live in a large apartment building so I cannot rewire.
Has anybody else not been able to resolve this problem and had to give up on analog? Digital is perfect. It is so unfortunate because vinyl has an intoxicating compelling sound like nothing else.
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@roxy1927 No. What happens if you move the arm towards the label but off of the LP? If the hum shows up its a sign the motor might be making noise. But if the hum only shows when on the LP surface, its an indication the motor mounts have perished or something similar- causing the platter to vibrate slightly. What happens if the platter isn't moving and you set the needle down on an LP? The Allnic head preamp clearly has a problem. It could simply be a bad tube. That is the first thing I’d check. It could also be a poorly grounded connector or bad ground somewhere in the head preamp itself. If you’d like to use it again, I’d have it tested by a technician.
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I've had RFI issues with a few phonostages. Ironically, one was an original Schiit Mani; supposedly they fixed that with the Mani 2; the other was a Lehmann Silver Cube, which was a real disappointment for a unit at that price. I believe the root of the problem is poor shielding in the power supply. I had moderate success with adding ferrite chokes onto the power cord. It's a cheap thing to try with your Allnic. I would loop the cord around the choke to increase coverage, or even use a couple of chokes. I also wonder if the antenna you mentioned earlier is for a Ham radio transmitter. The timing of that with your issues seems suspect. |
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