Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Meridian Prime + PSU - upstream and downstream

Ok, so how silent is silent and dead quiet?

Replacement power supply has a hum. Not tried it in same room or different mains circuit as before, and I don't think it's as noticeable as the original (which I could hear humming a few meters away), but probably would not want to sleep with it beside me - which was always an option.

I'll probably end up bringing it into work again - different county let alone ring main...

I've got a feeling that I may be hyper sensitive to low frequency hum. My wife cannot hear our ventilation system at home and she is the one who claims to have the better hearing, but I can hear and locate the quiet low frequency hum from some vents - I'm not confusing this with noise from the Prime - I can hear and differentiate both at the same time. Bit of a pain when I have mostly permanent high frequency tinnitus and SWMO's dulcet mid tones nattering away - no escaping the noise...

I'm hoping that it's a noisy batch of PSU's though.

You are welcome to bring it over and compare/test on my mains here. I have normal, dedicated rings, dedicated radials and also a PS powerplant. That should be enough.....

Me too. One the reasons why I got rid of my Naim amps - 4 of them hum quite loudly. I did find that the hum level varied from day to day which may reflect differences in the quality of the mains supply. A Bryston amp which has a DC filter built in was silent even with its substantial toroidal PSU.

This is the nub of the matter, no?

Indeed! However, some manufacturers do exacerbate the problem by design, e.g. Naim where the transformers are tightly bolted against the case resulting in a resonance effect. I reduced the noise of a NAP100 amp significantly by inserting a few rubber O-rings. Probably invalidated the warrant but what the heck!

My G95 didn't like my mains and a laser printer on the same ring main made things worse until it went pop. The toroidal buzzed like if was trying to get out of the case. In the end I made a DC trap and it cured it.

I can't find the exact one I made, This one looks very much a similar design and may just be a newer version.

Richard

Ditto. I had one pair of 5K's in one room that would transformer hum randomly.
Added D.C. Filter and no more hum.

Friend has D2500 sub that would transformer hum randomly. I loaned my filter to him and no more hum.

$119

Emotiva CMX-2

Anyone know of a similar device - at such a good price - for European mains?

This worked for me.

Considering the price of Prime PSU, one wonders if one is not already built in and if not, why not.

You'd think $20k to $80k speakers would have it too, but they do not.

All linear power supplies I've seen from Meridian (as well as many other brands) have the toroid transformer connect directly to mains.

The D.C. Offset filter needs to be before the transformer. Because it's the transformer itself that sometimes hums.

That's the one I built and it works very well. Not currently in use if anybody wants to give it a go.