12V DAC PSU

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Cressy Snr
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#1 12V DAC PSU

Post by Cressy Snr »

Over the weekend I knocked up a linear power supply for the Beresford DAC. It replaces the wall wart switching supply I have been using.
I have been encouraged recently by the bits of regulation I added to the front end of the 45 amplifier, so I thought I'd give a linear regulated supply a go for the DAC.
The Beresford TC7510 is a budget DAC and has long since been superseded. The original Beresford DAC was a bit of a Marmite product. Some people thought is was the best thing since sliced bread and others thought it was fizzy and congested. I liked it, and to me, in standard format with the wall-wart supply, it sounds better than my MF M1 DAC, less hi-fi and more music compared to the M1.

I built the supply into the enclosure formerly occupied by a Tangent CDII budget CD player, which ages ago had packed up on me. It was only a year old and frankly I couldn't be arsed to send it back. The lack of gapless playback pissed me off big time and if I had known about that 'feature' I wouldn't have bought the bloody thing in the first place. When it started refusing to read discs and muting at random, for no apparent reason, I'd had enough and bought a 1980s Philips 16 bit player off our Ant for a few bob. This has given no trouble whatsoever (touch wood) and sounds very nice through the valve system. Again it is less hi-fi and more music.

So here is the supply, built into the redundant CD player case:
DACPSUinterior.jpeg
DACPSUinterior.jpeg (185.53 KiB) Viewed 2630 times
Last edited by Cressy Snr on Tue Nov 02, 2021 5:51 pm, edited 1 time in total.
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Cressy Snr
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#2 Re: 12V DAC PSU

Post by Cressy Snr »

And sitting in the system, between the turntable and the amplifier:
DACPSU.jpeg
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Cressy Snr
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#3 Re: 12V DAC PSU

Post by Cressy Snr »

The power supply is a standard CLC feeding a textbook 12V fixed regulator, that uses a 7812cv fixed voltage IC, mounted on a heatsink, configured as per the application note.
The low value choke is in there because Bruce Rozenblit recommends them in power supplies to filter out HF hash. It is certainly very quiet; in fact it is completely silent in operation.
Here's the diagram:
DACPSUSchematic.png
DACPSUSchematic.png (42.29 KiB) Viewed 2626 times
It's pretty darned basic, and I'm sure there are plenty of ways to make it a bit more sophisticated, but it certainly makes the DAC sing. I've never heard it sound as good as it does now. Black silences, good image, great bass, detailed mids and smooth, extended treble, as far up as I can hear anyway.
Still a budget DAC. No illusions and all that jazz, but despite all that, it works nicely.
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Cressy Snr
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#4 Re: 12V DAC PSU

Post by Cressy Snr »

Well, looking about on the information superhighway it would seem that in the case of the Beresford TC7510 DAC, it’s all been done before, a long time ago (2008) and was sanctioned and encouraged by none other than Stanley B himself.
There is a long thread on AoS, with contributions from several folk on here, and it would seem that I haven’t even scratched the surface with this basic linear power supply, so apologies for my naivety to all you intrepid modders who passed this way 13 years ago.
Everyone has long since moved on, TC7510s are collecting dust in sundry lofts and cupboards, I’m a lot older and have neither the eyesight nor the manual dexterity required to carry out even the simplest mods to the DAC board itself, let alone the more involved ones such as changing out op-amps.

I’m stranded in a long-forgotten digital backwater but whatever. I can’t think of anything more I need or want on the digital side.
Last edited by Cressy Snr on Wed Nov 03, 2021 12:15 pm, edited 4 times in total.
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Ant
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#5 Re: 12V DAC PSU

Post by Ant »

Can i have the m1 then? :mrgreen: pleeeese
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pre65
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#6 Re: 12V DAC PSU

Post by pre65 »

I'm not familiar with your particular Beresford DAC, but some, like my SEG, are better running at a higher voltage.

The PSU I made for my SEG is set at 15V, as approved by Stan himself.
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Cressy Snr
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#7 Re: 12V DAC PSU

Post by Cressy Snr »

pre65 wrote: Wed Nov 03, 2021 12:34 pm I'm not familiar with your particular Beresford DAC, but some, like my SEG, are better running at a higher voltage.

The PSU I made for my SEG is set at 15V, as approved by Stan himself.
Cheers Phil,
Yes, I noticed he talked about 15V for the TC7510 too, which makes me wonder why he ran things at 12V out of the factory. Maybe 12V wall warts are easier to come by and cheaper. I can jack up the output of my PSU to around 14V with a red LED in the common pin of the 7812 IC, bypassed by a 22uF cap. Might try that later on. I need to sort out the output cable as it’s only lashed up to a bit of tag-strip at the moment; no strain relief whatsoever. I’m not having that.
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Cressy Snr
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#8 Re: 12V DAC PSU

Post by Cressy Snr »

OK, so I've installed a red LED and bypass cap, inline with the common pin on the regulator IC, and now have a rock steady 13.85V DC out. I'll set about the output cabling arrangement now.
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Cressy Snr
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#9 Re: 12V DAC PSU

Post by Cressy Snr »

Regulator board with added red LED and cap:
820ACAA2-0C81-4510-ABD2-6A4ECB019070.jpeg
820ACAA2-0C81-4510-ABD2-6A4ECB019070.jpeg (155.35 KiB) Viewed 2537 times
LED lifts the common pin, 1.85V, above the nominal.
Power now leaves the unit via a spare insulated phono socket I had knocking about, so nothing can now pull on, or away from anything inside the case. I’ve made up a cable with a phono plug one end and a suitable DC connector for the entry to the DAC on the other.
Meter reads 13.85V of regulated DC. That’ll do nicely.
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Cressy Snr
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#10 Re: 12V DAC PSU

Post by Cressy Snr »

New PSU diagram:
DACPSUSchematic13.85V.png
DACPSUSchematic13.85V.png (42.72 KiB) Viewed 2507 times
Seems a bit more opened out in terms of the depth and width of the soundstage. Interesting.
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