Paul Hynes PSU for Caiman DAC

[MartinT]

This is part 1 of my rebuild of the Beresford Caiman DAC and my original external power supply to incorporate Paul Hynes' power supply regulator modules. These will replace the SuperTeddy in the external PSU box and the Dexa regulator modules inside the Caiman.

Many enthusiasts, and I am one of them, believe that great audio components are practically defined by the quality of their power supplies. This is my attempt to go all-out for the best performance possible from the already excellent Caiman, using power supply modules made by Paul Hynes.

Showing the PR3 +16V regulator module for the external PSU and the two S17LNS2 regulator modules for the +5V and +12V internal voltage rails (coming in part 2).


Offering up the parts in my stripped-out PSU case and things are looking tight. As it turned out, the transformer was the incorrect voltage for centre-tapped rectification and needed replacing. Its replacement (0-15V, 0-15V, 50VA) was slightly smaller - phew! I snuck a Nichicon MUSE capacitor into the external capacitor connectors in the hope of better high frequency reservoir performance.


The PR3 now attached to the front panel. Heatsinking is not really an issue due to the small load current drawn by the Caiman (as it turned out, there is precious little heating up at all).


Adjusting for exactly +16V output. No need to worry about on-load adjustment as I doubt the voltage drop is at all significant (my Caiman has passive coupling caps with no op-amp board so there is precious little +12V draw). That LED is bright!


The completed external PSU in place and operational. Those old Hi-Fi News Flux Dumpers are perfect for the job.


So how does it sound? Considering I haven't given it much time to burn-in, the answer is significantly better than the SuperTeddy. I am hearing a wealth of tiny details and aural cues, bass is tighter and the overall soundstage is well defined and very transparent. Sound quality from Sky HD over optical and Blu-ray over co-ax are equally superb, as well as CDs using the Sony as a transport. The Caiman is not normally used for CD playback in my system, but I would be very happy indeed with it, it really is a DAC in another league altogether when fed from a power supply like this.

The SuperTeddy is well known for being an ultra low noise regulator design, but to the detriment of current and instantaneous peak delivery. The PH PR3 design features heavily in transient power delivery and is no slouch in the noise stakes, either. It seems that the Caiman, and particularly the Wolfson 8716 DAC, benefits from being fed by a meaty, over-spec'd PSU.

Ancillaries: Multicomp MCTA050/15 0-15, 0-15 50VA transformer; Kimber PBJ DC cable; Maplin project case, really very bright blue LED.

Part 2, replacing the internal regulators, will come soon.

[Reid Malenfant]

Lovely pics Martin, however you make the PR3 look simple All the real control is on the back of the PCB & is surface mount components, then it starts getting complicated

I have a PR3i powering my Octava HDMI switcher, the difference between that & a regulated (non SMPS) wall wart defies description

On with the thread

[MartinT]

Oh I agree Mark. All of Paul's modules are full of cleverness with SM components on the back. I have sat and stared at them, trying to get the circuit in my head, and given up.

[Paul Hynes]

Hi Martin,

Thanks for taking the time to set this up and report your findings. That LED is bright! You can adjust the light output by increasing the value of the axial resistor to the right of the reservoir capacitors until you have the desired light level. This will have to be trial and error depending on the spec of the LED you have selected.

Hi Mark,

Nice to hear that the PR3 worked well with the Octava.

Regards
Paul

[Butuz]

Excellent thread!

Butuz

[MartinT]

That LED is bright! You can adjust the light output by increasing the value of the axial resistor to the right of the reservoir capacitors until you have the desired light level.

Yes indeed, it's just a matter of taking it apart again. I think I'll start by at least doubling that resistor value

I've left the PSU and DAC burning in all night and today with some Sky MTV, which should get it into its stride. Further listening tonight.

[John]

Lovelly write up Martin

[HighFidelityGuy]

Nice one Martin! I can see I'm going to have to invest in some of Paul's power supplies next year.

EDIT: I seem to remember that someone else looked into using Pauls regulators in the Caiman but came to the conclusion that there was an issue with dropout voltage (or something like that) that would make them unsuitable. I may have remembered that wrong but perhaps someone can clear that up?

[Clive]

Nice one Martin! I can see I'm going to have to invest in some of Paul's power supplies next year.

EDIT: I seem to remember that someone else looked into using Pauls regulators in the Caiman but came to the conclusion that there was an issue with dropout voltage (or something like that) that would make them unsuitable. I may have remembered that wrong but perhaps someone can clear that up?

The dropout voltage on Paul's regs has been between 4.5V and 6V IIRC. The variation is down which components were used for a specific board. I think Paul had recently re-worked the regs, I don't know if this has changed the dropout voltage. For the first reg inthe Caiman it seems like a PS outputting at least 18V would be needed, this is for the previous version of the regs.

[MartinT]

My 15-0-15V transformer gives 21V raw DC [15 x sqrt(2)], which is perfect for the PR3 to supply 16V (5V drop). When I next open up the Caiman I shall remove its protection diode so as to feed the new regulators with 16V direct and eliminate the 0.6V voltage drop.

P.S. don't do this if you have the original 16V reservoir capacitor in place.