Balanced line mains

[_D_S_J_R_]

I admit I never did what you've done, but old Naims are terribly mains sensitive as you've confirmed. I DO respect your ears, honestly...

[Gromit]

A much better photo of the beastie...

DSCF1943

Ok, then - what does it actually do?

We all know (DSJR espesh ) that the 42.5/110 isn't exactly what you'd describe as a shrinking violet. Violent is perhaps a more apt description. Still, I quite like it and enjoy its front-row presentation. Adding the BMU...

If you've heard what a HiCap does to a Naim pre-amp, this will be fairly familiar but not only does the presentation with BMU added gain scale, it's as thought someone has put a metronome behind the music. Best way I can try to describe it is this - without it, there's less sense of the time domain in music being wholly accurate. Imagine a turntable playing at varying speed, but without changing pitch, and you'll hopefully get the idea. Add the BMU and the timing is restored to clockwork precision, the temporal smearing being removed. Of course, music still ebbs and flows against this, but in a much more accurate and realistic way. I'd also say taking the BMU out of the system makes its contribution all the more obvious.

Sonically (as opposed to musically) it's a shot in the arm for the amp's ability to portray colour. Acoustic piano (which I listen to 50% of the time) gains body, it resonates for longer and its physicality is improved too. High frequencies integrate better into the mix, and are no longer a separate sprinkling on the top just to give a sense of extra detail - the HF of the Sapphires is now sweeter, less obvious. They were always clean at the top, it's just that there's always been a little too much of it.

At the risk of 'gushing' now I've experienced what the balanced mains can bring, I'm not not wholly sure I'll be happy to live without it.

[terrybooth]

The 15 amp plug version, unless my eyes deceive me.

[_D_S_J_R_]

Riched, any reason there's no NVA amps at present? Are you just having a change?

[terrybooth]

Riched, any reason there's no NVA amps at present? Are you just having a change?

I think that's the 'show pic' which will end up on eBay.

[Dr Bunsen Honeydew]

Well he can reply but NVA amps are out of the equation now as he is one of the three people in the history of NVA who has a house?, main? RF field? whatever? that NVA amps cannot cope with. Dave your AP20 is the one that went to Gromits for photograhy and at his place, like all NVA amps at the moment, it was unlistenable. The amps are taking off, latching up, going unstable, and I have modified and modified for him and made it a little better but cannot remove entirely the problem. The BMU was my last attempt to cure it and it hasn't. So basically I have spent so much time on the problem now I have given up as three amplifier one in France, one in Switzerland and one in UK (Gromit) is not a big problem and if it happens again I will just refund.

So Gromit cannot use NVA amps until he moves or I somehow come across a cure. That is not a presumption that he would do, but he doesn't have that choice.

[Dr Bunsen Honeydew]

The 15 amp plug version, unless my eyes deceive me.

Its 13amp. the problem is I haven't settled on a final socket style and it will vary in look dependent on if 13 amp 15 amp or Schuko.

[Gromit]

What the Doc said above.

I would most certainly have entertained the idea of another NVA amp but it seems, despite the amps to-ing & fro-ing from Lincs to NVA Towers for modifications there's not been a cure found. I briefly popped one of the amps round to our neighbour's place a few weeks ago but the problem still existed there so there's clearly a local issue. What that is, I've not the foggiest idea.

There did seem to be some loose correlation between amp size and the amount of instability - the smaller amps (notably AP10P & AP20) were least affected.

[terrybooth]

What the Doc said above.

I would most certainly have entertained the idea of another NVA amp but it seems, despite the amps to-ing & fro-ing from Lincs to NVA Towers for modifications there's not been a cure found. I briefly popped one of the amps round to our neighbour's place a few weeks ago but the problem still existed there so there's clearly a local issue. What that is, I've not the foggiest idea.

There did seem to be some loose correlation between amp size and the amount of instability - the smaller amps (notably AP10P & AP20) were least affected.

Sorry. Can't resist a problem.

If the problem exists at both your house and a neighbours house, it would appear to be mains based and not something specific to your property. (how far away was the neighbour?).
If that's correct, then anything that links to the mains (dedicated spur, BMU) isn't going to help. But would a mains regenerator help? If I've understood 'em correctly, they may help.
Doc - any thoughts?

[_D_S_J_R_]

I was genuinely afraid that the AP20 I'm using would be a tetchy little bugger in use, but credit where it's due, it's as benign as anything I've ever used. No noises, just a very quiet 'plop' on switch-on and barely a whisper when the volume control is quickly advanced or retarded (a point made in the published review).

I went back to the HH power amp this afternoon. Nothing obviously wrong, but some of the enjoyment and subtlety seems to have dissipated from discs I played last night!