I'm loving this thread. I now realise that I MUST try the BMU!

Please can I borrow it after Chris?

Thanks

Steve

At least it wasn't a negative trial. For me, £4000 or more on a high performance regenerator is out there in dreamland sadly..

What would be interesting is to see how well amplifier power supplies filter off mains-borne distortion, although I think you may have sort-of covered this. The BMU should cancel out some types by its very nature I believe.

By the way, I did give strong consideration to trying P10 -> BMU but I didn't in the end as the BMU can, like any large transformer, be a bastard load (especially on switch-on) and I didn't want to blow up my nice regenerator. If anyone else wants to try it, feel free and report back!

I have been informed that running the BMU from a regenerator works fine. I haven't tried it so can't recommend it, but for the adventurous, give it a whirl.

Thinking about it, I must ask Paul McGowan if the P10 has a built-in DC blocker. I would have thought so, but it would be nice to confirm.

That may be worthwhile at some future point, Tony. For now, I'm revelling in what the Black Ravioli feet did for the P10.

Martin, please may I enquire how you got the results of your distorted mains? I need to try to justify elsewhere on a highly objective forum some comments I made regarding varying mains quality over different parts of the UK. I've experienced the *subjective* effects of varying and generally bad mains at different times, with different gear and in a few different locations hundreds of miles apart, but need to be able to provide a way of testing or quantifying this if I can. Any help would be appreciated.

Thanks, I'd appreciate that if it's not too much trouble.

I wonder if there's any legal requirement for standards of mains electricity delivery? I know some talented designers can effectively remove mains-borne interference in their power supplies (AVI's Martin Grindrod was very able at this, right from his Kelvin Labs days), but others using large capacity but simpler techniques may not be so lucky.

Here's my mains waveform raw (about 2.3% distortion).  Horrible, I think you'll agree.



Here's the output from the regenerator (0.1% THD). I have since set the output voltage to 235V for slightly better sound again.



Here's the correction applied by the P10 to yield the sinewave output.

Martin, I've enjoyed reading your thoughts and the comments of others.

I can add a little. I was lucky enough to also own a AG1500 together with a BMU. I fed the BMU from the AG1500 and initially I felt there was synergy. I found the AG1500 effective in eliminating transformer noise, with the BMU seemingly offering more in terms of palpable gain in musicality. I later formed he opinion that while regeneration had a 'silencing' effect, this may be achieved 'filter' style, with a potential detrimental impact on what I was experiencing. I subsequently passed the regenerator on, although I would be keen to try one again in the future, as it is clear that this is a constantly changing game. Quality of electrical supply may be a key variable in terms of where the most value can be gained.

I couldn't see any mention of transformer noise from the BMU unit in your posting. This is positive, initially this was a concern for me and I was considering locating the unit in different room to overcome this. However, my unit was one of the first produced and after receiving a tweak that all production units now receive, it is now far less of an issue. Any noise appears to be supply dependent, the unit is mostly silent and if there is noise, it is generally only noticeable without music playing and passes quickly.

I have used an extension cable when I have needed more than four sockets. I have had six A80 monoblocks running, in addition to other kit, without any perceived load issue. I actually find the top mounted sockets to be no concern, although I am increasingly afflicted when it comes to trying to keep cables tidy etc! I will get some pictures up at some point to try and illustrate. I see that the loan unit has the plain sockets, where I have the 'blinged' up gold/brass look. I actually prefer the bling, but fully appreciate that all may not share this opinion.