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In the Forum: Audio Discussions
In the Thread: It’s mad, mad, mad... electricity.
Post Subject: More on the PP/phono situationPosted by N-set on: 11/6/2020
Thank you for the feedback guys!

- Bill and drdna below is the actual physical situation. The distance to the Decca is 110cm, to Phono 140cm (the noise is present even if I switch to a shorted MM input and the PP is on batteries). Looks like I will have to play with the physical separation and orientation. Not much space though to move away the unit PP and give how LOUD the interference is, I'd have to move it to another room almost. BTW, drdna the Decca/London is the Reference, which I think you know well Smile Indeed a v sensitive cart (somewhat hums with my ungrounded TT, picking the EMT930 motor noise) but if the conditions are right it can play out of this world even a bit humming!!

- The interesting, and sort of encouraging fact, is that the FM tuna plays terrific and dead silent, being almost right above the PP. So far it was reacting to every RF it could pick. It picked even RF noise from Edison decorative bulbs (!!) about 2.5m away (!!) and I had to change them to high vacuum ones! When I head the first sounds of it connected to PP, I jumped up. The sound is magnificent, even with my current suboptimal antenna arrangement (mixed up the polarizations) and so-so musical material I've heard so far.

- PurePower, I might be wrong but this doesn't sound *at all* like a 50Hz hum. Especially with regular pulsations appearing from time to time (quite similar to 8Hz brumming from WiFi/GSM, I once picked, but orders of magnitude louder). Probably the pulsations are the battery charger kicking in. To me this sounds more like RF interference, making it down to the upper bass. I will check again the grounding, but it should be a perfect star with only the phono being grounded to the PP schuko socket and the rest, including the TT, floating. The phono cables are double and triple shielded. Actually the massive, ungrounded TT frame and the rack might be the culprit, will experiment with grounding them.  The AC cables are unshielded, with only a 'drain' GND wire connected at the socket end, a la Paul S recipe. Never had any problems with them and as I said this does not sound like a 50Hz pickup.

Hope to make it work.

PP position.jpg


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