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Posted 30th July 2014 at 09:06 AM by abraxalito
Updated 9th August 2014 at 12:30 AM by abraxalito

Here's a hexacap built with 10F caps, so the total capacitance is 610F. The individual caps have ESRs varying from around 30mohms to 60mhoms - I weeded out those above 60mohms with the aim of getting the ESR (and hence total impedance) below 1mohm for all audio frequencies.

The caps are rated at 2.7V which is plenty enough for powering a stack of TDA1387s. Just they take a while to charge up - with around 500mA being fed in the voltage takes almost an hour to reach 2.7V from cold. I've been forming them up and the leakage current seems to be stabilizing now, around 30mA, or 0.5mA per cap.

Update - I've installed this beneath a stack of 6 TDA1387s and been listening for a couple of days. The long and the short of it is there's now no going back to 'conventional' caps, supercaps are here to stay in my DAC designs. The improvement in SQ is rather hard to describe in words - its lower colouration to the LF which might be described as improved 'weight' or 'authority'. Its quite surprising to me how much colouration has been removed which I was previously totally unaware of - I'd just adapted to the normal sound of electronics in the LF region. Frank will probably know what I mean
There's probably still more PSU colouration to come out, so the next focus will have to be the AD815 buffer's power arrangements.... Perhaps two supercaps in series will have to be tried as they'll not work on 2.7V. But before that I think a discrete buffer needs experimenting with as it was that test which alerted me a few months back to PSU colouration.

Yesterday I got a box full of some Japanese made supercaps (Elna Dynacap) and there's no doubt the Japanese manufacturing prowess shows through - consistency of ESR for example is impressive.
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  1. Old Comment
    miklos's Avatar
    Excellent looking job, gratulations.
    I guess if one would get shorted, the rest would burn the short off.
    Posted 1st August 2014 at 10:48 AM by miklos miklos is offline
  2. Old Comment
    abraxalito's Avatar
    I have given that some thought - I've only had capacitors go short when overvoltaged though, they overheat and then explode. The total energy storage is about 2.2kJ but very high peak currents are possible so yes its entirely possible that one cap would have vapourized lead-outs.
    Posted 1st August 2014 at 12:58 PM by abraxalito abraxalito is offline
  3. Old Comment
    Indeed I do, ;) ... as I've said before, there appears almost no end in sight to how good the sound can get - 'weight', 'authority' are good ways to describe where the path takes you, a "massive" quality to the sound presentation can manifest, where the sound world created comes across as so much larger than where you happen to be at the moment, :). Ambitious 'pop' productions can become amazing places, where you almost feel you should get a ticket to enter, :p.

    Remarkably, this depth of presentation can be conjured up by very ordinary speakers, it doesn't seem possible at times - but that's the beauty of the ear/brain mechanism, making sense of all the cues ...
    Posted 10th August 2014 at 02:52 AM by fas42 fas42 is offline
    Updated 10th August 2014 at 02:55 AM by fas42
  4. Old Comment
    miklos's Avatar
    Provided at your brain know what you supposed to hear.
    If it's the first time one hear an instrument, or a music piece ,that mechanism has not much to rely on. You have to process information, a good speaker give more information.
    Posted 14th August 2014 at 04:58 PM by miklos miklos is offline
  5. Old Comment
    Yes, except I would state it as, a good system, rather than speaker - if a completely unknown piece of music, or style of music is heard for the first time, and makes musical sense then the system is in pretty good shape ...
    Posted 15th August 2014 at 02:21 AM by fas42 fas42 is offline

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