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nicpom

Power Supplies for Beresford DAC

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I read a lot of Posts about better power supplies for this DAC (and DAC in general).

Somebody tried batteries, others switching PS, other linear...

It seems that more than 12 Volt but less than 14 is beneficial, and as more current capability as possible.

Now I tried a linear regulated PS, 5 A, 1-15 Volt. A huge thing.

At 13.5 Volt, the sound was clearly worse! Reduced soundstage, less detail, congestion. Very bad. Checked with Stax electrostatic headphones directly connected to the DAC outputs. I am quite sure of these findings.

On the other hand, it seem to me that this PS is no so different from MAPLIN ones recommended here.

Surely I am missing something. :wall:

All opinions are wellcome. Thanks to all

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Too obvious to be likely, but is the PSU's output AC or DC?

Assuming it's a variable output have you experimented with lower and higher voltages?

Have you checked the o/p voltage with a meter? The PSU's claimed outputs are not always terribly accurate.

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Paul,

yes I did all these verifications and more (DC output and AC ripple and noise with a precision digital multimeter). I could carry the PS to my laboratory at work and test it with a digital scope, but i do not expect surprises. And what should I watch for, anyhow?

The problem is more subtle. That's the reason I am asking here :sos:

This resembles me other long discussions about NAIM external power supplies, whose series regulators are (according to Naim), carefully selected for their noise signature. And those supplies have a huge effect on Naim equipment (I can confirm this).

More, those supplies are often successfully substituted by custom made PS based on ultra low noise operational amplifiers. Like one of these:

http://www.at-view.co.uk/alwsr.htm

But, again, if many are obtaining good results with cheap PS, I should not need exotic ones.

Has somebody experienced bad results with some type of PS?

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There are a lot of reasons why one power supply might sound better than another, even when the other might seem to be superior. I am not sure it is possible to select a PSU on the basis of its specification and or design in some cases. It is better to identify 2 or 3 types that are said to work well and compare them, picking the one that suits your personal tastes best. One thing I would suggest is the nature of your headphones will make any shortcomings more noticeable. Is it possible the DAC simply doesn't stand up to scrutiny through such good headphones?

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Surely Stax are a sort of surgical tool to find out equipment shortcomings. Actually using them one also realizes that most CDs are poorly recorded to begin with.

On an absolute scale this DAC is not perfect (still very good), however on a relative scale, comparing its wall mart PS with my bigger, powerful, linear, higher voltage one, I can distinguish a difference and the latter is worse.

That's in contraddiction with other posts here, and also with common sense, but it is.

I was wondering if anybody had a similar experience, just to avoid the "brute force" approach of trying different PS until I found one good.

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Cable Monkey has a good point - the Stax will show things warts and all.

At 13.5 volts and a much higher current than specified you could simply be driving some of the output op-amps in the DAC too hard: some, including recent ultra-low noisetypes, have very tight voltage and current tolerances - push them too hard and they will sound pretty much as you describe.

Why not build your own linear PSU to the required specification? - it sounds as though you have access to all the right facilities, and designs abound on the net.

Good luck!

Edit: :doh:another blindingly obvious point - off-the-shelf variable output PSUs are invariably crap in my experience until you start throwing serious money at them.

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Yes I could realise my own PS. I need to better understand what are the parameters that really make a difference.

As some obtained good results with a dirty cheap PS only applying more voltage, I hoped that it was so simple. Hmm, audio is never so simple.:nup:

To be sincere, I also wrote to Stanley Beresford. As his DAC is so PS sensitive, I proposed him to optimise a PS and offer it as an upgrade. Who better than the DAC designer himself?

He answered that he would think about this....

Anyway, thanks to all for all the comments and suggestions.

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earl of sodbury wrote:

Cable Monkey has a good point - the Stax will show things warts and all.

At 13.5 volts and a much higher current than specified you could simply be driving some of the output op-amps in the DAC too hard: some, including recent ultra-low noisetypes, have very tight voltage and current tolerances - push them too hard and they will sound pretty much as you describe.

Edit: :doh:another blindingly obvious point - off-the-shelf variable output PSUs are invariably crap in my experience until you start throwing serious money at them.

Just to clear up some confusion:

The TC-7510 has a regulated internal power supply. So running it at anything above 12V doesn't make a difference to the supply rails.

The unit was designed to accept an external power source up to 14V in case anyone wanted to use it with an external power source other than the supplied one.

The variable power supply some of us picked up from Maplin is one of the best I have ever come across at any price. It's even better than teh 13.8V fixed power supply that they sell next to it.

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OK,

just to avoid misunderstanding, is it this?

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=48517&doy=8m6#spec

May I assume that this would allow to obtain the highest performances from the DAC?

This is a variable output, switching PS. Crap, from a flat-earth point of view.

So, or this one is a rare exception (I do not think so), or all the audiophiles spending for linear ultra filtered low noise PS or batteries are basically throwing out their money.

I am really tempted to try this one. If only mapling shipping costs were not so high..

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nicpom wrote:

OK,

just to avoid misunderstanding, is it this?

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=48517&doy=8m6#spec

May I assume that this would allow to obtain the highest performances from the DAC?

This is a variable output, switching PS. Crap, from a flat-earth point of view.

So, or this one is a rare exception (I do not think so), or all the audiophiles spending for linear ultra filtered low noise PS or batteries are basically throwing out their money.

I am really tempted to try this one. If only mapling shipping costs were not so high..

I am not here to challenge your perception of the Maplin power supply or variable PSU in general. It is possibly the most expensive variable PSU I have seen, but I did buy mine at GBP19.99 when it was on special offer a few months back:). All I can say is that I have a number of other power supplies, includng several variable ones, around the house. This particular Maplin unit gives me a level of performance that I didn't expect to be that good. Only my digital programmable GBP400 odd test bench PSU betters it.
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nicpom schreef:

Now I tried a linear regulated PS, 5 A, 1-15 Volt. A huge thing.

I dont know how much current the DAC draws, but some PSU's do not regulate very good at low output current, and since this is a 5 Ampere model ... ?

Just a thought,

Menel.

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Sranang_Boi wrote:

nicpom wrote:
OK,

just to avoid misunderstanding, is it this?

http://www.maplin.co.uk/module.aspx?ITAG=SPEC&ModuleNo=48517&doy=8m6#spec

May I assume that this would allow to obtain the highest performances from the DAC?

This is a variable output, switching PS. Crap, from a flat-earth point of view.

So, or this one is a rare exception (I do not think so), or all the audiophiles spending for linear ultra filtered low noise PS or batteries are basically throwing out their money.

I am really tempted to try this one. If only mapling shipping costs were not so high..

I am not here to challenge your perception of the Maplin power supply or variable PSU in general. It is possibly the most expensive variable PSU I have seen, but I did buy mine at GBP19.99 when it was on special offer a few months back:). All I can say is that I have a number of other power supplies, includng several variable ones, around the house. This particular Maplin unit gives me a level of performance that I didn't expect to be that good. Only my digital programmable GBP400 odd test bench PSU betters it.

This expensive PSU, surely, has much better technical specifications than Maplin PSU.

On the other hand, I beat that all the other cheap PSUs you own are technically very similar to Maplin one. So what makes it so special?

Assuming that by a pure accident they made a particular "musical" PSU for GBP20 as good as a pro GBP400 one, really are you not asking to yourself WHY is it so good? This would be a valuable information for a designer, IMO.

...but maybe this is the reason why you are so vague:whistle:

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nicpom wrote:

If only mapling shipping costs were not so high..

Maplin shipping is free if you spend £35 so just add a pack of batteries or somesuch to bring the total over £35.

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