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  1. Old Comment
    wlowes's Avatar

    6C33C OTL Amp Comes to Life

    Thanks Ryanj
    Now paired with your Distinction TDA1541a board there is some amazing sound coming from these beasts!
    Walter
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    Posted Yesterday at 12:13 AM by wlowes wlowes is offline
  2. Old Comment
    triode_al's Avatar

    Stock Status

    you should find a european partner
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    Posted 28th March 2015 at 10:39 AM by triode_al triode_al is offline
  3. Old Comment

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Is it not enough performance the deglitcher circuit on PCM64's datasheet which is canceling hold step?
    Although the schematic has misprint.
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    Posted 22nd March 2015 at 01:13 AM by Shinja Shinja is offline
  4. Old Comment
    fas42's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Just read that post by Baldr, from jcx's link - why do these people always seem to produce a strange mixture of heavy duty terminology, and handwaving puffery? Personally, I have lost confidence in the product from reading that - the impression is that that they don't really understand why it works as well as it apparently does ...
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    Posted 15th March 2015 at 02:26 AM by fas42 fas42 is offline
  5. Old Comment
    abraxalito's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Given the use of two chips per channel, I'd also go for the time-interleaved solution. Apparently they're running at 8X OS meaning one output sample per 2.8uS.
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    Posted 15th March 2015 at 12:32 AM by abraxalito abraxalito is offline
  6. Old Comment

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    I don't know if he making something special of mapping/function theory surjective,/injective/bijective distinctions - not really the way most engineers think about digital linear filters

    Hawksford's glitch avoidance technique is classic for his work - brilliant but dubiously practical

    but 2 DACs gives other interleave options - if you can mux with less DAC Vout dependence than the DAC glitch errors then you just Ping-Pong between the 2 time interleaved DAC, not looking while the code dependent glitch settles - virtual gnd mux should give just fixed clock feedthru without adding audio signal correlated distortion

    techniques I'm pretty sure I knew of 20 years ago


    the critique of S/H is interesting considering their Bifrost DAC uses a sw C filtered V out AKM DAC chip - kinda hard to see the difference between a S/H and every stage of a sw C filter
    of course some have been critical of "the sound" of sw C Vout DAC forever despite CS4398 being used in Lynx Hilo and lots of companies pro studio rack equipment
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    Posted 14th March 2015 at 03:03 PM by jcx jcx is offline
    Updated 14th March 2015 at 06:23 PM by jcx
  7. Old Comment
    abraxalito's Avatar

    My latest infatuation - transformers

    Resolution of the regulator output impedance issue here - http://www.diyaudio.com/forums/chip-...ml#post4254216

    Tom's provided measurements of the rail noise - 4mVRMS on the opamp supply +ve when playing out 20kHz at full power.
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    Posted 12th March 2015 at 07:06 AM by abraxalito abraxalito is offline
  8. Old Comment
    abraxalito's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    I didn't take the 'preamble' comment as applying to glitch control - its an aspect of the DAC that appears in the DS - see p19 where the input shift register bit allocations are tabulated.

    I agree about 'S/H sound like ***' says to me 'design a better one that doesn't'.

    Bit-perfect digital filter also raised a major BS flag for me. Perhaps he's talking about a particular kind of half-band filter which maintains the 'original samples' (as if they're something holy not to be touched) and inserts others in-between. But half-band filters rather suck - I recall having a discussion with Thorsten about this concept on DIYA many years ago.

    I shall have a look at your link, thanks for chipping in. OK had a read. I can't follow how it happens that because the algorithm to design the filter has closed form, therefore all the original samples are preserved. What steps am I missing? He seems to diss Parks-McClellan optimized filter design but I can't fathom why.
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    Posted 12th March 2015 at 07:01 AM by abraxalito abraxalito is offline
    Updated 12th March 2015 at 07:18 AM by abraxalito
  9. Old Comment

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Mike Moffat's "S/H sound like ***" comment suggests probably not using S/H - and is the annoying categorical audiophile guru type of "wisdom" claim that doesn't sit well with this engineer

    there was some other passing comment about calculating a "preamble" to each sample as part of the glitch control strategy

    using 2 (multiplying) DACs per channel does however suggest other possibilities:
    J30 DIGITAL-TO-ANALOG CONVERTER WITH LOW INTERSAMPLE TRANSITION DISTORTION AND LOW SENSITIVITY TO SAMPLE JITTER AND TRANSRESISTANCE AMPLIFIER SLEW RATE, Hawksford, M.O.J., JAES, vol. 42, no. 11, pp 901-917, November 1994

    which I painfully dug out of archive.org - can't easily repeat


    on head-fi I was savaged for daring to question the "bit perfect digital filter" as being dubiously relevant to home listening on practical noise and dither grounds - independent of what he really means by the term, however the digital filter works about which I made no assumptions

    now he has a "clarification" of the purported innovative "does the right thing" filter
    New Schiit! Ragnarok and Yggdrasil - Page 331
    using the term "holographic" kind of sends up flags

    I do sincerely wish them well - am eager to see the performance, circuit implementation
    willing to give full credit for taking a different path, possibly pushing past the dynamic performance limitation in the datasheet spec
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    Posted 12th March 2015 at 12:44 AM by jcx jcx is offline
    Updated 12th March 2015 at 12:58 AM by jcx
  10. Old Comment

    my projects:

    mister, is there any one build harry77 ampli?
    permalink
    Posted 8th March 2015 at 12:17 PM by spongeman spongeman is offline
  11. Old Comment
    rjm's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    @fas42 Bravo! Excellent little primer. Perhaps string DAC topology is preferable for audio then...
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    Posted 8th March 2015 at 12:26 AM by rjm rjm is offline
  12. Old Comment
    abraxalito's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Interesting comparison of the glitch energies of the R2R and string DACs there. The Metrum Octave is using a string DAC and got some rave reviews even though its measurements suck.
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    Posted 7th March 2015 at 11:59 PM by abraxalito abraxalito is offline
  13. Old Comment
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    Posted 7th March 2015 at 10:54 PM by fas42 fas42 is offline
  14. Old Comment
    abraxalito's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    In my understanding a deglitcher is either a sample/hold or track/hold. Needs some kind of switch to disconnect the DAC's output when its changing state. Jim Williams developed an OTA-based switch when he was measuring DAC settling time and this is described in detail in a Linear appnote here : http://cds.linear.com/docs/en/applic...ote/an120f.pdf
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    Posted 7th March 2015 at 10:50 PM by abraxalito abraxalito is offline
  15. Old Comment
    fas42's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Also demonstrates that somewhat bizarre choices for circuitry parts can work, if enough homework is done in all the right areas, to compensate for less than reasonable capabilities in supposedly key areas. One thing I certainly have learned over the years, is that the most unlikely audio components can get the subjectively critical things in the sound correct, if the right sort, ie. from knowledge and experience, of efforts are made.
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    Posted 7th March 2015 at 10:47 PM by fas42 fas42 is offline
  16. Old Comment
    rjm's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Could you share what a de-glitcher is though? This is the first time I've run into the concept.
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    Posted 7th March 2015 at 10:28 PM by rjm rjm is offline
  17. Old Comment

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Yes, my argument was from the static accuracy perspective. There is the glitch issue of course with these non-audio chips which can and must be engineered around.

    Mike could have picked a chip with less accuracy and better glitch characteristics, but you can't exactly engineer around poor DNL/INL.

    I have some idea what they did to get around the glitch issue, but I am not a liberty to say for obvious reasons. The Internet is a vast resource, and they didn't do anything someone else hasn't already written about. There are hints inherent in the architecture as well.
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    Posted 7th March 2015 at 06:55 PM by marvchen marvchen is offline
  18. Old Comment
    scott wurcer's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    Needs a de-glitcher

    That DAC needs a heroic de-glitcher for audio. There was one designed at Weiss engineering but I can't share it.
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    Posted 7th March 2015 at 03:26 PM by scott wurcer scott wurcer is offline
  19. Old Comment
    abraxalito's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    From reading Purrin's postings on this thread - Thoughts on a bunch of DACs (and why I hate chocolate ice cream) - Page 190
    it does indeed sound like he's arguing very much from static accuracy. I chimed in on there with a link to this blog so we'll see what happens
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    Posted 7th March 2015 at 09:54 AM by abraxalito abraxalito is offline
  20. Old Comment
    rjm's Avatar

    Schitt's flagship DAC uses a not-for-audio DAC chip.

    It appears to be a low noise, very high accuracy part for medical/test&measurement applications. It wouldn't surprise me to learn that it wasn't ideally suited for audio ... though I suppose you could argue that its superb DC accuracy trumps so-so settling times, like you I'm not convinced.
    permalink
    Posted 7th March 2015 at 09:29 AM by rjm rjm is offline
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