Beresford Dorado 3 repair
In June 2021 I bought my Beresford Caiman DAC & had it updated a month later to SEG 50 with the supercap/clock mods I also bought a Dorado 3 It is not a stand alone power supply but rather an enhancement for existing regulated switch mode or linear mains adapters, I use a 15v 3 amp MCRU/longdog linear PSU driving the Dorado 3 which has internally 6 super capacitors to provide a more stable and faster power output, potentially revealing more musical details.
My Dorado 3 like a couple of others I had that failed by August 2021, though then still under warranty, failed & stopped powering the Caiman SEG 50. Mr Beresford seems to have closed up shop, no longer appearing on forums, his website effectively closed I know he had trouble getting micro chips in 2022. So I posted the small 2 cigarette packet sized Dorado 3 to a friend, Mark Manwaring-White at Malvern Audio Research to see if anything could be done with it.
My Dorado 3 LPSU/filter arrived back in the post this morning.
I had sent it to my dear friend & valve expert Mark Manwaring-White who tested it. He found that there was a defective thermistor on the PCB, it had as I had suspected, when he Whatsapped to update me a few days ago, now confirmed, that it was reducing 15v DC to less than 3v DC at just a few milliamps. Which might explain the other 2 similar failures! & low output complained about by ASR when they tested a Dorado 3.
Mark felt the thermistor was there to limit current inrush with poorly designed PSU's/wall wart SMPSU's. He then removed the thermistor & wired it out of circuit on the PCB. He told me this when I phoned him today to update & thank him, this was after about an hour of listening to YouTube & CD he told me that he also found many oxidised solder joints which he Resoldered.
Playing YouTube music today I noticed when switching/turning on, the system components that the Dorado 3 two colour LED did not light up immediately if I simply turned the MCRU 15v Linear PSU on, unlike it did from new, the Dorado 3 LED lit up only when the on switch was flipped then instant transition from dull red to bright green showing charged.
The addition of the Dorado 3 to the Caiman SEG 50 DAC released so much more fine background detail & all around cleaner presentation than the combination had before, what it does I know, how it does it, I do not know. But 6 super capacitors in series at 2.5v = 15 very clean filtered volts?.
This may be of help to others.
