Balanced Power Supply

[Ali Tait]

Having a (very) rare weekend off, I finally got round to building my BPS. I'd previously bought the 3kva trannie from a member here who'd bought it as a prototype. However, it was just mounted in a box with no protection whatsoever. Should never have been sold like that IMHO as it was potentially a very dangerous state of affairs if there had been a fault whilst it was in use.

Anyway, I bought all the bits and pieces several weeks ago, so set to this morning, jigsawing out for the IEC and double mains socket. I used an electrical wall mount enclosure to put it all in as it seemed the easiest solution. Not the prettiest, but as it's tucked away unseen it doesn't matter.

I have fitted an MCB on the primary, as well as a double pole RCBO on the secondary to keep everything safe.

http://img33.imageshack.us/img33/259/dscf0084sj.jpg (http://imageshack.us/photo/my-images/33/dscf0084sj.jpg/)

Below can be seen the IEC chassis plug, 30A NTC thermistor surge limiter and a DC blocker board that was kindly donated by Nick (Thanks again!) The thermistor is needed to counteract inrush on switch on tripping the MCB's in the CU. Blocker board is doing a great job, trannie is now totally silent whereas before I fitted it, there was some mechanical hum. A great result.

http://img24.imageshack.us/img24/5256/dscf0083wp.jpg (http://imageshack.us/photo/my-images/24/dscf0083wp.jpg/)

Below the cutout for the double socket and the MCB and RCBO wired up-

http://img688.imageshack.us/img688/7964/dscf0082d.jpg (http://imageshack.us/photo/my-images/688/dscf0082d.jpg/)

I also fitted some steel heavy-duty lifting handles as it's bloody heavy, about 40kg I'd guess.

So how does it sound? Well, had it powering the system for about an hour now, and there is a definate improvement. Not night and day, but I was already using a couple of Belkin mains conditioners. Low level detail is definately improved though, and the soundstage seems more focussed, but not shrunk any, if that makes any sense. All in all a worthwhile invesment I think.

[John]

Good one Ali
Neat work

[Barry]

Looks good Ali! Any chance of knowing the circuit details of the mains DC blocking board? Those capacitors don't appear to be big enough.

[Ali Tait]

Thanks chaps. Don't know the details of the blocker Barry, perhaps Nick will comment. Certainly it's working with no problems so far. Nick knows what he's doing though, I've every confidence in his designs.

[daytona600]

can,t see the type of merlin gerin breaker used ali , Type B or C
Abb make 2p Mcbs type K for transformers / motors to avoid nuisance tripping
or good old fuses ideal for transformer inrush 10x38mm Din rail mtg fuseholders

[Ali Tait]

Both type C. I had some inrush problems, which is why I fitted the NTC. Been fine since.

[daytona600]

type K is a special type by ABB with a mag trip designed for T/x & Dol motors Ali
thermistors & type C as you say works fine
increase in sound quality a bit or lots , never tried a isolation trannie before
might try and build one myself one day

[Ali Tait]

Guess it will depend on the quality of your raw mains, but yes, seems to have been a worthwhile exercise.

[lurcher]

Looks good Ali! Any chance of knowing the circuit details of the mains DC blocking board? Those capacitors don't appear to be big enough.

Why?, almost no power goes through the caps in my design.

[Sovereign]

Very interesting Ali,
I used to have a 3.4Kva Airlink balanced transformer that I found made a good and positive difference to the sound of my hifi, I lived in the middle of town then right next to two factories and the transformer hummed like mad. Are you still using your DC blocked before the balanced mains transformer?

[Ali Tait]

Yes, the mains comes in and through the blocker, then feeds the transformer.

[Barry]

Why?, almost no power goes through the caps in my design.

I had in mind this: http://sound.westhost.com/articles/xfmr-dc.htm. I assume you use a set of anti-parallel diodes as the main current path.

[lurcher]

yes though i intentionally make the esr of the caps look worst to make their life beter and damp the lc circuit formed with the following transformer.

[wee tee cee]

Heard this device in action on Saturday.....it made a substantial improvement to a well resolved system.Enough of a difference for me to purchase a lesser equivalent from Airlink on line when I got home (after pleading with my better half of course)....Mains make a significant,palpable difference in my limited experience.

[brian2957]

Got to agree Tony . Had a bit of a jaw dropping experience when this was put into the system . So much so that all other upgrades are put on hold until I can purchase one of these . Can you post your findings when you get one of these into your set up mate . Ta much.

[Ali Tait]

Yes, even I was surprised by the level of improvement. Tony, have you ordered yours yet?

Try and change it if you have, the 2kva is only a few quid more.

[Gazjam]

Yes, even I was surprised by the level of improvement. Tony, have you ordered yours yet?

Try and change it if you have, the 2kva is only a few quid more.

Inc Vat and Delivery the 2VA is £341.
The 1.5VA is £293

In my kit Ali (valve amp, server and Dac) would the 1.5 be enough for me?
Any sound quality/ remove risk of running near full load improvemnts going up to the 2KA?

Not much in it price wise...forgot to add VAT in though! :doh:


ta.

[Ali Tait]

I'd say the 1.5 would be ok, but why not go for the 2 as it's not much more?

[Ali Tait]

Plug your telly in to it too, makes the picture better on mine.

[Gazjam]

aye.. cant think why not to. :)

[Gazjam]

as theres only two sockets, would there be much of a hit quality wise using a standard mains block to connect more bits of kit?
Suppose something decent wouldn't do any harm?
Without getting all obsessive aboot it of course :)

I noticed my plasma gets better with a decent mains cable, so room for improvement there.

[Ali Tait]

Might be worth making something yourself? Pretty easy to do, and should save a few quid on a bought one.

[wee tee cee]

ordered the 1.5 its all i can stretch to...will let you know how i get on.with vat and postage it was 3 ton.after what i heard i think it will be a good investment for infrastructure regardless of future change. i would never have believed the difference if i hadn't heard it with my own ears....

[Sovereign]

ordered the 1.5 its all i can stretch to...will let you know how i get on.with vat and postage it was 3 ton.after what i heard i think it will be a good investment for infrastructure regardless of future change. i would never have believed the difference if i hadn't heard it with my own ears....
Glad your liking the improvements.
I had the 3.4Kva one, where you hard wire it into your house mains, I loved the difference it made.
I am about to sort out may mains in my listening room, but maybe next year when finances allow I'll dip my toe back into balanced mains.

[Gazjam]

another jaw dropping moment in my system, more so (Id say) than fitting Ali's TQ Black speaker cable in my Rega speakers.
As Brian said, its a no brainer in my system.

it too is on zee list. :)

[Sovereign]

have you already ordered the airlink transformer?

[Gazjam]

Me?
Not yet James, will do though.

[brian2957]

Have you got the AG1500 James ? . If so how does it compare to the balanced unit. I'm not sure which to go for myself.

[Sovereign]

Have you got the AG1500 James ? . If so how does it compare to the balanced unit. I'm not sure which to go for myself.

Yes I do have the AG1500, very hard to say how they compare as I had my balanced tranny about three years ago in a different house, I couldn't really compare sorry. But I can say that they both made a worthwhile improvement.
Some guys put the balanced mains after the AG1500 and notice a good improvement. If I do go for another balanced mains that is the route I may go down, but not 100% sure yet. I do know that I'm not getting rid of the AG1500

I'm trying to find a Saturday when I'm either not working or not got family commitments so I can upgrade my mains supply to what it should be.

[brian2957]

Thanks James . I'm not in a position to buy either at the moment and I'm hoping Gary will bring his balanced unit over to mine to try . If I get the same improvement I heard at Garys place the decision will be made for me.

[Sovereign]

Where are you?

[brian2957]

About 10 miles East of Glasgow mate in a place called Cumbernauld .

[Sovereign]

Are there any AoS members in the South East!:doh:

[brian2957]

:lol: Dunno mate but I've been lucky enough to build up a friendship with a few relatively local AOS members up here and we've had a couple of cracking mini bake offs . That's where I heard Alis excellent balanced unit ( Saturday ) . The Scottish MacMafia goes from strength to strength :eyebrows: