HiFi Subjectivist ¦ Audio Forum ¦ NVA User Group

Thank you very much to Nick for testing the Metrum Onyx and finding no faults with the unit your time and effort is very much appreciated .

Well *something* is causing it, so far *something* has killed A100's, A80's and A40's, and killed amps have taken out some drive units as well. I cannot go on for ever I am in severe loss making situation already. It would be cheaper for me to just refund.

The only thing I noted was that there was no output filter on the DAC, but I dont think that would have any impact on the amp. It won't be the only dac that did that.

My cdp has no output filter and nothing bad has happened with my nva amp boards

In this video review of the Pi / Allo DigiOne board. Dutch Hifi commentator Hans Beekhuyzen has identified a problem caused by switching wall-wart power supplies causing disturbances in the rest of the system.

Starting at 5.18

Allo DigiOne SPDIF board for Raspberry Pi

I am very worried about the designs of these new DACs, it is not co-incidence I now have another problem. When BMU used DAC starts breaking up and misbehaving, take BMU out problem stops. So obvious choice run the DAC on the wall socket and the rest of the system on the BMU - DAC still starts to miss behave.

BTW this is at a customer not here my VERY SIMPLE cheap Chinese DAC has no problems with BMU or seemingly anything.

Dr Bunsen Honeydew wrote: ↑Thu Dec 20, 2018 11:23 am I am very worried about the designs of these new DACs, it is not co-incidence I now have another problem. When BMU used DAC starts breaking up and misbehaving, take BMU out problem stops. So obvious choice run the DAC on the wall socket and the rest of the system on the BMU - DAC still starts to miss behave.

BTW this is at a customer not here my VERY SIMPLE cheap Chinese DAC has no problems with BMU or seemingly anything.

If thats the chap using a MDAC via one of my power supplies, I have asked him to check the voltage out of the BMU as the voltage out of the power supply makes me think that its got a low mains voltage input which is causing the regulated supply to fall out of regulation.

Yes he has a low voltage transformer as I have found them best. So I now match the secondary to the low point in UK mains as so many people seems to be over voltage. I have one guy consistently at 248v. I am aiming now for 215 / 220v for 240v in. If you order primary and secondary to be the same then you fall foul of the regulation which boosts out voltage by about 10v.

If that is the problem I can swop for a higher secondary voltage one as I can do 120/120 or 115/115 or 110/110 or even in extreme cases 100/100. It is almost becoming me sorting out the voltage feeds being all over the place.

then you fall foul of the regulation which boosts out voltage by about 10v

But only off load.

I am aiming now for 215 / 220v for 240v in

Ok, but if thats the off load voltage, then fully loaded that would be 194/198

Worst case if they had 220v on their line, that would give 178v/182v fully loaded.

Doesn't do that as a hi-fi doesn't load a 1000va transformer, the regulation always seems to be there. I have measured when listening to music and not connected and the difference is 1 or 2v.

But as I say if that is the problem then I will swop his one for a higher voltage one. For me here I prefer the lower voltage one, and it doesn't bother anything NVA, as interest once I ran a 240v amp on 120v and it worked fine, it was just clipping came in earlier as the voltage rails had halved, so problems depend on design.