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The BMU Bandits

Posted: Wed Jun 19, 2019 5:01 pm
by Fretless
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Every time that I, or just about everyone else, asked RD what I could do to upgrade my system his invariable answer was 'BMU - and then the rest'. It must have been about 4 years ago that he started using/making them and on several occasions I have been on the point of buying one, but never quite got around to it.

So, the legacy of 'The Doc' has been that the current stock of available NVA units has been offered at a substantially reduced price. He won't be building them anymore, which is a sad thought, however this has finally given me the necessary kick to acquire the BMU I kept saying to him that I would get. Whenever I look at it, it will be a reminder of him.

Balanced Mains Unit. The idea is logical - normal AC runs in a sine-wave from 0 volts to 240 volts, 50 times a second. The BMU has a transformer that alters the voltage from +120V to -120V. Still having the 240V difference to power equipment but the plus and minus voltage is now 'balanced', in harmony, equal, whatever.

The nice man from UPS appeared at my door and handed over a largish and rather heavy package. In the usual perfect NVA wrapping was concealed a mysterious black box. A single mains lead ran out of it and four mains sockets sat on the top, somehow bigger - and more imposing - than expected. An uncomfortable half-hour of rearranging mains-wire spaghetti ensued and finally things started to get turned back on.

Immediately there was silence. Not just any silence but an empty silent void waiting to be filled. Sounds come, music, instruments, effects. I slammed through a selection of tracks just to get an idea of what was going on.

Space - the final frontier!

It's the room that everything gets. And this is most noticeable on acoustic instruments. I put on Michael Hedges 'Aerial Boundaries' and instead of being blown away I was sucked inside. There is a liquid serenity that just holds you gently in the music and you simply don't want to leave. It took me three tracks to realise that the one I had wanted to hear had long finished. Then onto Rachel Podger's magnificent recording of Biber's 'Rosary Sonatas'. Not just am I hearing far more in the sense of nuance and inflection. The whole recording is a natural, living entity that you can literally walk into.

Oh dear, looks like i'm in gush-mode. Better rein it in.

Sorry Richard, it took me a long time to get here.
You were right, again.

Time to blast back off into the infinite space ...
So, in the immortal words of James T. Kirk:
Beam Me Up, Scotty! :sci-fi-beamup: :sci-fi-beamup: :sci-fi-beamup:

Re: The BMU Bandits

Posted: Wed Jun 19, 2019 5:21 pm
by southall-1998
Nice write up. Always kept meaning to buy a BMU to try on my system. Looks like I'm too late to the party. Might try an isolation transformer instead.

S.

Re: The BMU Bandits

Posted: Wed Jun 19, 2019 5:23 pm
by scotty38
Great write up! I, too, was tempted by the offer....

Re: The BMU Bandits

Posted: Wed Jun 19, 2019 5:29 pm
by _D_S_J_R_
I don't have the parts here, but Tom currently has access to them when he's here and I believe in the last year he probably made them all to order, as they were too expensive to stockpile, unlike the preamps and A20's for example. If you're serious about buying one, why not PM him and see if he can help next time he's over here?

Re: The BMU Bandits

Posted: Wed Jun 19, 2019 10:53 pm
by CN211276
The BMU was the first piece of NVA equipment I bought and it made quite a difference to my then modest system. What I noticed was that SQ became consistent as well as improving over all. I put this down to poor mains. I am noticing that the time it takes to charge devices varies and think this could be down to poor mains and variations in current.

Re: The BMU Bandits

Posted: Thu Jun 20, 2019 10:13 am
by Classicrock
I was one who tried it. My mains are pretty decent so any changes in SQ were swings and roundabouts for me. Also i suspect it did nothing for the Albarry amps and made my buffer stage buzz loudly. I should have tried it on sources only. I suspect it may be most beneficial with digital components in my case as TT PS is a Michell Never Connected design. As Doc said it's a try and see component. It isn't a universal solution. I suspect RA may have been copying some NVA thinking on their latest BMU versions. Wouldn't rule out trying one again however.

Re: The BMU Bandits

Posted: Thu Jun 20, 2019 4:53 pm
by karatestu
I stopped using mine a little while ago. Couldn't hear any difference when i removed it. May put it back in and see if i detect anything.

Re: The BMU Bandits

Posted: Thu Jun 20, 2019 7:33 pm
by Fretless
Maybe Dutch mains are noisy - quite possible with all the heavy farm machinery in the area here.

Re: The BMU Bandits

Posted: Thu Jun 20, 2019 11:19 pm
by Fretless
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BMU rather unceremoniously dumped in front of system.

When I have the time there will need to be some organising and arranging here.

The white plugs are for the A40's - they're simply ghastly dahling. They'll really have to go. :eusa-hand:

Re: The BMU Bandits

Posted: Fri Jun 21, 2019 5:27 am
by Firebug1
Maybe you shoud buy some fancy he plugs from mcru or ra... :lol: