Electrician specializing in audio needed Buffalo

Al thanks for your input. I am actually referring to my Frankensteins. The very latest incarnation of the Frankensteins have a ground lift switch. This afternoon I discovered that the source of the problem may actually be an inexpensive CD player (with a captive two prong AC cable) that I have been using to break in a new modification done to the Frankensteins. When I switched from the CD player back to my turntable, the hum was gone and no need to lift the ground; the hum returned as soon as I reconnected the CD player.

I will conduct the experiment you suggested at some point this coming week and report my findings here.

Thanks for the nice words, gentlemen.

As is usually the case, I agree with everything Jim has said. Including the fact that the ground lift switch can be presumed to not interrupt the connection between chassis and AC safety ground. In contrast to using a 3-prong to 2-prong cheater plug to defeat the AC safety ground connection, which is sometimes done to resolve ground loop problems despite the safety risk.

07-19-15: Tmmvinyl
Does lifting the ground on my power amplifiers do anything to degrade the amp's sonic capabilities?

As Jim suggested, it would probably be worthwhile asking Mr. Blume. (I assume, btw, that you are referring to your Coincident Dragon amps, as I don't think the Franks have a ground lift switch, based on their description at the Coincident website).

There are many conceivable effects that can depend on the position of that switch, and most of those effects tend to be system dependent and to generally have little predictability. But keep in mind that if setting that switch to the "lift" position resolved the hum problem, it may also have resolved other adverse sonic effects related to the ground loop that was present. Even effects occurring at frequencies that are themselves too high to be audible, but that may have had audible consequences by intermodulating with audible frequencies in the audio signal.

Also, an experiment that may provide added confidence would be to disconnect the input cable from each of the amps (leaving the speakers connected!), and using a multimeter to measure the AC voltage, if any, between the ground sleeve of the RCA input connector and chassis, on each amp. That would provide an indication of how far the circuit ground of the amp "floats" from chassis, when the switch is in the "lift" position. If the reading is small, say just a volt or two, it would provide added confidence in using that switch position. Have the amp turned off, of course, when you disconnect the input cable, and then turn it back on for the measurement.

And BTW, in the absence of specific information to the contrary I would not change the position of that switch while the amp is powered up, or within the first few seconds after turning it off.

Best regards,
-- Al

Agreed; Atmasphere and Almarg are welcomed in any discussion. Thanks again.

Thanks again Jim. Does lifting the ground on my power amplifiers do anything to degrade the amp's sonic capabilities?

Jim,

Thank you for all of your help.

I used three dedicated runs of Oyaide solid core 10 AWG wire from three separate breakers in the panel to three separate outlets dedicated to my power amplifiers and my direct drive turntable. Each run is fully visible from the panel to the outlet. The cable was not run inside conduit because the City inspector did not require it. I used two dedicated runs of Cardas solid core 10 AWG wire to two separate outlets dedicated to the power supplies for my phono stage and line stage preamplifiers. These two runs are also fully visible from the panel to the outlets and were not run through conduit.

I had previously checked the outlets with my voltmeter when first installed and found zero volts when checking outlet to outlet.So I had assumed everything had been properly run off of the same leg.

My mono power amplifiers have a ground lift switch. When I flip the switch, my system is dead quiet. I just don't like the idea of having to defeat ground to achieve silence. This seems dangerous to me.

Thanks again for your time.

Jim, thank you for responding.

I have two separately metered services into my home. One service is solely dedicated to my listening room. The panel sits directly beneath my listening room. I have 5 dedicated runs of solid 10 AWG wire from 20 amp breakers to 5 in-floor Furutech duplex outlets. The longest run of wire is 11 feet. All wiring is fully exposed and none of it travels through the wall. Getting this work done, required three different electricians, not one of whom had any interest in listening to me or in following my instructions. I am now looking for someone who can properly ground my installation because I am still dealing with a fair bit of hum.

Rleff,

Thank you for suggesting the Speaker Shop; I hadn't thought about them. I have spoken with a number of electricians but none of whom have any real audio-specific experience.

There must be some Local 41 guys looking for some extra cash from side jobs; do you see anything in the buffalo evening news or any of the bee magazines (Amherst,clarence,etc...) Maybe the guys at the speaker shop on main street can give you some contact names to try.