Are you sure it isn't a ground loop problem? Ground loop hums are easy to eliminate.
13 responses Add your response
I have ers everywhere (one of the Stillpoints people is a friend ;-) but I don't think that would solve your problem.
But before you ditch that lovely amp (or the cute dog) could you describe the connection(s) between your TT/TA and the phono pre, including: brand of phono cable and termination(s), ground wire(s), and brand of TA.
I have Nuforce 9SE's and have found the Stillpoint ERS material to make a material improvement in the sound. However, they did not solve the problem I had with both amps humming. After E-mailing Jason at Nuforce, I found the answer lies in AC grounding. Do not float the grounds on the amps and if possible have the amps and preamp connected to the same circuit. That solved the humming problem for me. Good luck. Jason may have further suggestions.
I was using Discovery cables for the whole vinyl chain. I have been changing out cables, MIT, Nordost and Radio Shack, none of them resolve the buzz issue. I even tried wrapping the cables in aluminum foil, did nothing to help. I can move the cables and that also will affect the level of the buzz, similar to an antenna affect. I don't remember having this issue with the previous phono pre, ARC PH-5. At least it wasn't bad enough for me to notice. With the BAT pre I had this issue without the turntable connected. That is another option, replace phono pre and i would rather replace the amp than the phono pre.
I replaced the Nuforce with my Anthem amp and the buzz went away, That's how I figured out that it's the Nuforce amps.
I am only using balanced for the amps, I don't have balanced inputs anywhere else. It is not a dedicated line,but I will be having that done in the near future.
I have satelite tv and do not have this issue with anything but the phono playback.
I had the same problem with a pair of early vintage NuForce Reference 8 amps that caused noise in my phono stage. In fact I ended up selling that phono stage thinking it had some issues, but now I realize that it was the RFI from the NuForce amps that caused the noise. This was an expensive solid-state phono preamp. In that same system with the NuForce amps, a Musical Surroundings Phonomena phono stage worked fine -- I guess it had better shielding. Also, The TAD-150 tube phono seemed to be okay.
You didn't say which NuForce amps you had or which vintage they are. If they are the older Reference 8 amps, (below version 8.02) they probably don't have the RFI chokes on the speaker output wiring, in which case you can return them to NuForce and have the RFI supressor chokes installed.
If they are a newer model, and they have the chokes (you can see them if you remove the covers) then another approach would be to move the NuForce amps as physically far away from the BAT phono as you can manage. Perhaps use long interconnects and put them on the floor by the speakers. I have another system set up that way and there is no phono interference at all. But that one uses a MM phono preamp and not the higher gain MC phono amp. I think that if your NuForce amps have the supression chokes and you separate them from the BAT phono by a fair distance you shouldn't have any interference issues.
Good luck, and let me know how you make out.
I had a similar problem after purchasing a bel canto eVo6 which is also a switching amplifier. The amp forced me to clean up my AC. I removed all dimmers and flourescent lamps and installed a Dayton videa isolation transformer on my FM antenna cable lead and grounded my Marantz SR7200 chassis to my BBT PP1 power strip. My system is dead quiet now and I like the the amps power, tone, efficiency and the fact that it is good tool for testing the quality of your AC. I had ordered Stillpoints ERS cloth(6 adhesive sheets) before performing the above mentioned steps and it arrived after I had quieted my system. I lined the inside of my amp and Marantz DV8400 with the ERS Cloth anyway. I'm not sure if it made a difference but I have been very pleased with my system and have not had the urge to make any big changes.
My friend had a funny idea. Line the inside of a hat with the ERS Cloth. Has anyone tried this. I bet Harvey R. (Gizmo) would have.
Here's my guess: the NuForce amps are injecting RFI back into the power lines and emitting it in the air, so your BAT phono, which amplifies much smaller signals than line level, is most vulnerable. You can try installing a power conditioner (such as Exactpower or PS Audio products) where different outlets on it are isolated from each other, and use different outlets for the NuForce and BAT. On top of that, you can plug in noise filters into various AC outlets, like the Audioprism quiet line filters, AC Enacom and PS Audio Noise Harvester. Lastly, as Hals_den has mentioned, an isolation transformer should be able to completely isolate the amps (or phono) from AC noise. That takes care of the AC part.
Stillpoint ERS can partially filter out RFI/EMI emission from the amps, which is beneficial as well. There's also a device called Quantum Symphony Pro, which is designed to "neutralize" airborne RFI/EMI. It makes a big difference in sound, but I'm not sure if it removes the noise in your case. If you put all your gear on a rack, e.g., your phono in the middle and the amps at the bottom, you can stick a piece of u-Metal or copper foil at the bottom of the shelf supporting the phono, thus protecting the phono from being attacked from the bottom by the amps.
I gave up and sold the Nuforce, I love them, but time to move on. Now I have been scouring the ads for a replacement. Really having a hard time picking something. Should I or shouldn't I go back to tubes? Monos? Should I just buy something to tide me over until something really enticing hits? I have been wanting a VTL ST-150, but they don't show up very often.
My speakers are Von Schweikert VR4jr's and my pre is a VTL TL-5.5.
Thanks for all of your input on the RFI issue and sorry if I dissappointed you in my selling them off.