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In the Forum: Audio Discussions
In the Thread: It’s mad, mad, mad... electricity.

Post Subject: And what did you expect?Posted by Romy the Cat on: 1/24/2013

SOS wrote:
Well after getting little communication from PP I decided to sell my unit. The last communication from them was on 1-7 here is their response: Hi Steve, The reports you have provided are giving us valuable clues to the cause of the noise, but are not definitive. We do not think it is a fault in the unit you have. i.e. your unit is probably operating properly. The problem is that there is an interaction or connections somewhere that exists when you plug your phono equipment into the PurePower that allows ground noise to enter your pre-amp. We are running some simulations here to try and reproduce the effect and develop a way to ameliorate it. We hope to have a definitive answer mid next week. (We are scheduled to visit CES the last half of this week.) So now it's Jan 23rd and have heard nothing from PP. Maybe my unit is working as designed but I've heard from 2 other customers of the same scenerio while the original worked fine until the new 2000+ was installed and they got a hum. Very strange but unfortunate. Oh well time to move on. Suggestions?

…and what did you expect? There are absolutely no “simulations” they might run in order to “ameliorate” the problem you had. No one could rebuild the installation you have and to connect it in the way how you connected it. Juts be reasonable in your expectation. I am pretty sure that under normal circumstance there is no hum from the unit, juts because there is absolutely nothing in the unit that might be responsible for making ground loops more or less prominent. I am absolutely convinced that outputs of the units are grounded; I am sure that impedance of that ground is very low and this ALL the PP can or cannot do. Anything else is the external problem of the unit. Just be responsible with your expectation. You can’t not expect them to fly to you and to fix the problem with you own system ground loop. It might have “some” sense if you had hum with anything you connect to the unit but if you have absolutely normal hum-free operation and only develop hum what you use your TT motor then it a clear indication that it is your problem, not PP.

Come on, Steve! If you sell step-up transformers to for many customers who have no noise problems and then one of them report that with his cartridge your transformer has hum then would it be reasonable to suggest that the problem is not in your step-up transformer but in the way how this transformer is your in that specific installation?

You buy or sell PP - that is completely up to you. Frankly, dealing with ground loops is not the PP’s prerogative and if I run PP I would not promise to you a fix on PP side but would flat deny the complain. I still feel that you did not invest your own efforts to find the source of your ground loop but it is your rights to do or not to do.

BTW, if you report that you have 2 other customers with the same scenario then it might be indicative of slightly different problem. You are a dealer and I very much presume that your customers sue some kind of equipment that you sold to them. Most likely it is the same equipment that you use in your own installation. I give you 99.99% probability that the very same analog component that you all share between all 3 of you is the guilty party in your ground loop problems. It might be cartridge, TT, arm, phono cable, STU, phonostage or a way how everything is connected. This is common for passive and particularly balanced phono devises that they might have internal grounding problems that might be highlighted or reveled only under certain operation conditions. Perhaps PP is the condition that let this defective component to indicate your ground problems.

All that you need to know that you did NOT provide the specific of you problem and that PP with grounded output, even theoretically could, not be a SOURCE of the loop. I am very confident that if you call me when you were dealing with the problem I would find your loop but as you sold the PP not it is not necessary. If you find another power devise that works for you than let me know but I am afraid that to find another active devise with PP-level sound would be orders of magnitude more complicated then to fix your ground loop.

Saying all of it I need to mention that I did not have the new PP+ but if they have low impedance ground on outputs than there is nothing to see in there in order to rule out their responsibility for your problem.

The Cat

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