Noise from phono. Help please.


Recently became an analog fan and currently experimenting with different phono stages (ASR basis excl., ARC Ph7 and ayre p5xe.) System includes Avid Acutus, triplanar arm which comes with RCA connectors and ground wire. ARC ref3 preamp, VAC amp and Avalon speakers. System is quiet with cds but when a phono was added, noise became an issue.

The Ayre is very quiet and there is very faint background noise that is not audible at 8-10ft from speakers. (Vahalla XLR to ARC preamp) IC position doesnot change noise level.

ARC ph7 has some noise (buzz, hum). It is audible when no music is playing but when music is playing it is not an issue. What is strange is that when I change the position of the interconnect (single ended Cardas) connecting the phono to pre, the amplitude of the noise increase and decrease markedly. The PH7 is quieter at my friend's system in a dedicated circuit.

Noise is loudest with the ASR, amplitude varies with the positioning of the phono cable, interconnect. Interestingly, when I was leaning over the ASR phono, noise also decreased. Noise is present even when the tonearm is unplugged from the phono. Noise doesnot change with shunyata hydra in or out. I used to have a Hovland preamp which had a low level hum which completely went away when RF filter was installed by Hovland.

Guys, please advise me on how to reduce hum/buzz.

1) IS this due to RF from the powerlines (needs dedicated circuit ) or is it from RF in the air?

2) How can I shield RF in the air?

3) Is the RF picked up in the tonearm cable, phono stage or interconnect? I assume that the main culprit is the IC and possibly the phonostage because when tonearm cable is unplugged, noise is still there?

4) Is grounding issue involved?

thanks in advance
128x128glai

Showing 1 response by rlawry

I have had hum/noise problems in the past and have reduced it by trying various grounding schemes. Yes, the noise is probably RF and EMI being picked up by cables which act as antennas. It sounds as if your equipment is at different ground potentials and the noise is not draining out to a true ground. So what you need to do is get some wires and try grounding chassis screws/grounding posts, etc to each other and to a known ground such as the grounding plug on an AC outlet. Recently I had this problem when I bought a new turntable and ended up grounding the turntable and phono stage together, and then to the ground on an AC outlet. I would avoid the use of cheater plugs (convert 3-prong to 2-prong plugs) to lift the ground, as you may create a dangerous electrical shock condition.