Do they make a quiet great sounding phono pre amp??

mattmiller

I was able to place two 3to2 adapters on all components EXCEPT the main amplifier, I think by doing this the system is now funneling the grounds down to the one outlet, and now its quiet as a mouse!!

Do you mean that you've used adapters on all of your components other than one amplifier to defeat their AC safety grounds? If so, how do you think those disconnected grounds get "funneled" to one outlet?

I was able to place two 3to2 adapters on all components EXCEPT the main amplifier, I think by doing this the system is now funneling the grounds down to the one outlet, and now its quiet as a mouse!!

Matt, correct me if I'm wrong but I believe you are saying that you placed 3-prong to 2-prong adapters (also referred to as cheater plugs) on the AC power plugs of components, using them with the safety ground pin left unconnected, and that the reference to "two" adapters means that you put one on the power plug of the preamp and one on the power plug of the phono stage.

If so, what you've done is to break a ground loop between the phono stage and the preamp, that was causing the noise.  If you search past threads here dealing with the use of cheater plugs to resolve ground loop issues (which can take the form of hum or high frequency noise or both) you'll find that some people have utilized that approach as a permanent fix, while others passionately argue that it creates a completely unacceptable safety risk.  The risks being fire and shock.  And also the possibility that if a major fire were to start in that room, use of cheater plugs could conceivably provide your insurance company with an excuse to not pay.

FWIW my opinion on the matter is that while the risks are **extremely** small, it cannot be said that they are zero.  Personally, I would consider using cheater plugs to resolve ground loop problems to be a solution that is acceptable in the short term but not permanently.  Good permanent solutions would include inserting a suitably chosen Jensen transformer between the phono stage and the preamp, assuming that what I said in the first paragraph above is a correct interpretation (post back if you'd like more information on model selection), or changing one of the components to something else, or in the case of a responsive manufacturer asking them if they can change the internal grounding configuration of their component to one that is less susceptible to ground loop issues.

But those are just my own feelings on the matter.  Others have different views in many cases, as I mentioned.  And of course it's your call. 

Regards,
-- Al
 

+1 almarg! Very well stated Al!

I have used cheater plugs a few times to troubleshoot, or narrow down the culprit piece of gear. I would not use them as a permanent fix though.

Another way to deal with the ground loop without resorting to cheater plugs is to use a full wave bridge rectifier installed between chassis ground and audio ground, in either your preamp or phono stage, or both.  You install it such that the diodes provide the isolation between the two, but there is only a ~2V voltage drop (that of two diodes in series) between audio and earth ground, which ain't going to hurt anyone.  You would need an experienced tech, unless you understand the theory. A simpler method is to use a low value resistance, like 100 ohms, to separate the two grounds, which might or might not work.  Meantime, like Almarg, I don't think the danger of what you have done is so great as to cause panic.  The un-grounded components are in contact with earth ground via the ICs, assuming that your amplifier's earth ground and audio ground are in continuity.  OR, even simpler, you might find that re-arranging the plugs so that they all come off the same AC receptacle would permit you to go back to using 3 prongs. 

lewm

.... even simpler, you might find that re-arranging the plugs so that they all come off the same AC receptacle would permit you to go back to using 3 prongs.

This is the closest to the best solution to this common problem, imo. The hum/noise is caused by a differing voltage potential in the grounds. Relying on grounds of equal voltage potential will eliminate the noise. That's a benefit of using properly installed dedicated lines.