Balanced Power Supply

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Dr Bunsen Honeydew
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#166 Re: Balanced Power Supply

Post by Dr Bunsen Honeydew »

Nick wrote: Fri Aug 18, 2017 12:36 pm Well, AFAIKS, a CB that only monitors the L+R for imbalance and doesn't actively monitor earth current wont see the fault condition I mentioned. The fault current will pass from the secondary of the transformer, through the user, to the water pipe, to the PG of the house, back through the earth to the transformer and to the centre tap of the secondary. Never altering the L + N current so not being seen by the CB.

If you DO have a CB that monitors earth current, then it will trip, but then your household is not protected with a live to water pipe condition (as they weren’t before with wire fuses).
All I can say Nick is I did all the safety checks I could think of and the unit and me and the equipment plugged into it were protected.
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Ali Tait
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#167 Re: Balanced Power Supply

Post by Ali Tait »

Nick wrote: Fri Aug 18, 2017 12:36 pm Well, AFAIKS, a CB that only monitors the L+R for imbalance and doesn't actively monitor earth current wont see the fault condition I mentioned. The fault current will pass from the secondary of the transformer, through the user, to the water pipe, to the PG of the house, back through the earth to the transformer and to the centre tap of the secondary. Never altering the L + N current so not being seen by the CB.

If you DO have a CB that monitors earth current, then it will trip, but then your household is not protected with a live to water pipe condition (as they weren’t before with wire fuses).
I fitted an RCBO on the secondary for that reason, the earth fault overcurrent would trip it.
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#168 Re: Balanced Power Supply

Post by Cressy Snr »

To be fair to Ali, the biggest load of cobblers ever written by mankind on that AoS "discussion" about BMUs was by our old friend, the electrically qualified accountant, Oldpinkman (Pinky). Anything Ali may or may not have written, pales into insignificance alongside that eejit.

What with his lightbulb experiments, his Trading Standards threats, and his poking around in a live amplifier looking fir an earth loop, whilst holding an earthed metal object "safe in the knowledge that the MCBs on my house distribution board will protect me" everyone, even Marco came to the conclusion that he was a obviously a complete lunatic and should never be allowed anywhere near anything with electricity in it.
Last edited by Cressy Snr on Fri Aug 18, 2017 1:15 pm, edited 1 time in total.
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Nick
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#169 Re: Balanced Power Supply

Post by Nick »

Dr Bunsen Honeydew wrote: Fri Aug 18, 2017 12:43 pm
Nick wrote: Fri Aug 18, 2017 12:36 pm Well, AFAIKS, a CB that only monitors the L+R for imbalance and doesn't actively monitor earth current wont see the fault condition I mentioned. The fault current will pass from the secondary of the transformer, through the user, to the water pipe, to the PG of the house, back through the earth to the transformer and to the centre tap of the secondary. Never altering the L + N current so not being seen by the CB.

If you DO have a CB that monitors earth current, then it will trip, but then your household is not protected with a live to water pipe condition (as they weren’t before with wire fuses).
All I can say Nick is I did all the safety checks I could think of and the unit and me and the equipment plugged into it were protected.
I am sure you did Richard, I was just thinking out loud about what set of conditions would defeat the setup.

I know for example I once made a stupid mistake with a power supply once that didn’t cause a problem here (neutral and earth swapped). But tripped the newer installation at David’s shop when tested there. (He PAT tests stuff anyway, so it would never have got out).
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Ali Tait
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#170 Re: Balanced Power Supply

Post by Ali Tait »

Cressy Snr wrote: Fri Aug 18, 2017 1:12 pm To be fair to Ali, the biggest load of cobblers ever written by mankind on that AoS "discussion" about BMUs was by our old friend, the electrically qualified accountant, Oldpinkman (Pinky). Anything Ali may or may not have written, pales into insignificance alongside that eejit.

What with his lightbulb experiments, his Trading Standards threats, and his poking around in a live amplifier looking fir an earth loop, whilst holding an earthed metal object "safe in the knowledge that the MCBs on my house distribution board will protect me" everyone, even Marco came to the conclusion that he was a obviously a complete lunatic and should never be allowed anywhere near anything with electricity in it.
I would reiterate, if there is a post I've made on this subject that's factually incorrect, please let me know.
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#171 Re: Balanced Power Supply

Post by Ant »

Ok, now having a listen to some vinyl with the balanced power in place. The deck, phono stage and f5 are all running off it.
The immediate difference is that the lenco is quieter. Rumble has dropped quite alot. The motor vibration is noticably less with it in place. My lenco has a shimmed bearing; there is a solid shim underneath it so that it is directly coupled to the round baseplate. It basically stands in this shim and is bolted into the chassis plate so is clamped.dead rigid. This is so that bearing vibration is grounded out through the baseplate into the spikes, and out into the slate base. Alis and Daves have this done to them too. It stops the chassis plate sagging on the motor side due to the weight of the motor causing the platter to end up down slightly on the left and side. It makes the deck sound sharper and cleaner, but makes it abit more susceptible to rumble if the bearing and/or motor is worn. So changes in motor noise show straight up.
The balanced power has quietened it right down, so keeping all the mains shit out of the motor has made a huge difference to it. Its gone razor sharp, and it was sharp as it was.
I think an individual balanced psu would be a cracking upgrade for any idler driven deck running a squirrel cage motor.

Tbh, it seems to have had a large effect on the vinyl side of the system, the imaging is much improved, and again it was pretty good anyway. It seems that the phono stage has responded well to it. The f5 it doesnt seem to have affected very much, I say this as the digital side ( mac, beresford and cd 160 as a transport) seems better, though not to the same degree.

Seems going balanced power was worthwhile doing.

Wonder if nick could do a 47v linear supply for the phono stage, its responded well to balanced power so i reckon a decent main psu would make a significant difference
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#172 Re: Balanced Power Supply

Post by jack »

Ant wrote: Sat Aug 19, 2017 4:31 pmWonder if nick could do a 47v linear supply for the phono stage, its responded well to balanced power so i reckon a decent main psu would make a significant difference
This is not the "Nick" you were looking for (waves his hand in an obsure, Jedi, way...), but...

...have you considered a capacitor multiplier discrete supply?

Very simple, compact and very very low noise & ripple...

e.g. Elliot Sound Capacitor Multiplier
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#173 Re: Balanced Power Supply

Post by Ant »

I felt the jedi mind trick!
Nope meant t'other nick, and the psu's he and dave do for various things.

Ive not seen that on the esp site, i'll have a good look at that
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#174 Re: Balanced Power Supply

Post by Nick »

Cap multipliers get my vote.
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#175 Re: Balanced Power Supply

Post by Ant »

Well after a couple of hours of thrashing the nuts off the system as loud as possible with heavy metal and rock, nothing has blown up, or set on fire, and none of the magic smoke has been let out of anything.

So id say this particular bmu is a success
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#176 Re: Balanced Power Supply

Post by jack »

I suppose I should post the isolation/balanced/protected supply I use for testing valve radios & amps etc.

Not DIY - mostly COTS... Picked up an s/h 600W medical isolation transformer - an ISB-060W for 50 quid a while ago - they appear on eBay from time to time - very nice units. Followed that with an RCD spur on a IEC 60320 C14 fly lead - most of my workshop power is provided via IEC C13 managed strips that I salvaged from computer racks (APC AP7851s or similar) so a lot of my bench stuff is on C14 cables... Makes it all small & compact. I got my strips free when clearing out a computer room, but you can pick these up for about 200 quid or less on eBay - they make awesome bench PDUs...
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#177 Re: Balanced Power Supply

Post by Neal »

Finally got around to trying the 1Kva isolation transformer I bought from Phil a few years(!) back. Boy am I fast!

After trying the ‘fuse’ replacement game last week by eliminating them and then not getting anywhere with it I was intrigued if a BMU was going to make any difference.

With my 2A3 PP amp. the BMU made no difference as far as I could tell…maybe just maybe on one track a bit more clarity but I wouldn’t bet anything on being able to tell if swapped without me knowing. I think I’ll put this down to the 2A3 having a well designed PSU (even if I say so myself ;) ) and also down to Mikes excellent HT eChoke/regulator board.

Moving on I plugged in the Lenco G99 and my phono and was immediately taken aback. Flipping’ heck, Ant was right the Lenco likes balanced mains and as it turned out also my phono stage but to a lesser degree. One example, Al Stewart, instead of sounding slightly nasal, squeaky and a bit sibilant actually sounds like a bloke now and not a girl :D

Now need to box it up and find some space to house it…all this just when I thought I’d finished with this stuff!
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#178 Re: Balanced Power Supply

Post by Ant »

Yep that big old induction motor likes balanced power :D
Phils transformers are perfect for a 4 socket balanced mains unit, i settled on having the type 2 lenco conversion, the 2 phono stages and the f5 plugged in.

The balanced power didnt seem to make a blind bit of difference to the jvc deck, or the beresford dac. Made a little bit of a difference to the modified Philips cd371. It seems to make a teeny bit of a difference to the f5, but the hothead phono stage im using with the lenco seems to like it, the xlps im using with the jvc really likes it, and it made a big difference to the lenco. Seems to smooth the motor out quite abit and cuts vibration down, which I turn drops the decks noise floor.

It seemed to make the jbe smoother too, maybe the cleaner mains helps stability in the fairly rudimentary psu
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#179 Re: Balanced Power Supply

Post by Neal »

Interesting Ant, your experience more or less mirrors mine. Will be interesting to try it with my SP10.
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#180 Re: Balanced Power Supply

Post by Neal »

Listening some more this evening I’m reminded of where I was with the Lenco a few years back when it was still in its 1970s box plinth. Then I was running the GH242 with my Kontra B, the combination was sublime but somewhere along the way I lost the direction.

The KB needed a retip and it was sent away to Expert Stylus who had it for many months, in between I messed about with other decks and cartridges including the PL-71 and Denon DL-103SA. The Pioneer and Denon had something but didn’t quite capture the same performance of the Lenco.

When the KB came back I put it onto my Slate SP10 / SME309 and yes it is good but…..something still missing.

I find it intriguing that with Ant’s lovely plinth the GH242 and AT33PTG/II the balanced supply has got me back to where I was previously and some more…

The AT is a stunning cartridge for the money and Im happy this combo seems to be bringing out the best in it.

Note to ones self….don’t mess with it!

OK gushing over…..
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