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Help: Where are DPA Digital?

Discussion in 'audio' started by Yeldarb, Mar 7, 2004.


    DPA_SERVICE Active Member

    There was an upgrade for the PDM 1 seres two; upgrading it to a PDM 1 series three. However, you would need to send your dac back to DPA Digital for a rather lengthy modification process. But as DPA Digital no longer exist, that process is impossible.

    As for The Little Bit, it was never designed to be upgraded, however, as the chassis was the same as the PDM 1 series two, often I would use a spare board as an upgrade. Sadly, I do not have any spare PDM circuit boards.

    If you own a Bigger Bit or The Little Bit series two which occupies the same chassis. I have working Enlightenment Dac DX32 circuit boards which could upgrade the Bigger Bit and Little Bit. I think the Enlightenment a good upgrade, certainly more detailed.

    I have the deltran circuit should you wish to add it to your dacs; just needs a little careful planning :)
  2. ash_dac

    ash_dac New Member


    Hopefully I have a PMD100 digital filter on the way. The PMD100 datasheet has a diagram of how to connect PMD100 to YM3623B. I think changing the filter might be the easier option....:confused:


  3. davidland43

    davidland43 New Member

    A most interesting discussion thread!
    I have a DPA Little Bit Ser. No. BD 627 - still going very nicely, but from so long ago I can't remember! Series 1 - the very dark green glass case that has no screening merit whatsoever (RF everywhere - TVs beware). Interested to see the availability of Enlightenment boards - if they are really better than what I've got. Quite happy to fit if dimensions / mounting points are same as for present unit.

    ;) David L
  4. martin clark

    martin clark pinko bodger

    That's definitely not a drop-in option...you'll need to come up with your own pcb for the HDCD filter, and hack it in between the receiver and dac with quite a lot of fooling -about.

    Nice to have the choice though..!
  5. ash_dac

    ash_dac New Member

    PMD100 arrived today (on an Arcam 8SE board).

    YM3623 to PMD100 connection is in the PMD100 datasheet (MSB first, right justified)

    As for the saa7350 I assume it to be setup for 'Sony format' (MSB first, right justified) . Not sure what the bits would be 16 bits ?

    Does anyone have the YM3414 datasheet? (I only have the YM3414)

    Any recommendations for pcb software?


  6. ash_dac

    ash_dac New Member

    After studying the saa7350 datasheet I think interfacing the PMD100 into the little bit will be a little harder! I haven't checked the saa7350 config but I'm assuming it's input is setup 16 or 18bit Sony format with a maximum dataword rate of 4fs!
  7. dpastern

    dpastern Member

    I'll post a PM that I sent to Tom in here, since I'm not sure if it worked (nothing in my sent box, but no error messages when sending). If anyone else has any suggestions...

    "Hi Tom,

    I felt it was better to send a PM rather than post in one of the threads about DPA (where are they)?

    I've just purchased a 2nd hand DPA PDM 1 Series 3, has a glossy case, and the serial number on a sticker on the back. It's handwritten, so most of it has rubbed off. I'll try and decipher it as best as possible and let you know (if you need it). I've upgraded from a DPA Little Bit II (bought brand new).

    I've noticed a couple of things and I'm not sure if they're warning signs on issues with the unit. Firstly, the Little Bit sounds detailed, has a large soundstage, midrange is a bit forward, as are vocals. When putting the PDM 1 Series 3 unit in my system, I've noticed several things:

    1. Thinner sound, more orientated to the top end. Some stuff with high treble content sounds unbearably bright. Bass is less than the Little Bit II, but I suspect that that's because it's actually tighter and better controlled. Midrange is recessed, as are the vocals, when compared to the Little Bit II. Some vocals have some slight sibilance as well, which I've never noticed with the Little Bit II unit on ANY recordings that I've played during the long period that I've owned it.

    2. The PDM 1 Series 3 unit has more details, and a wider/higher/deeper soundstage. I'm hearing a lot more things than I've ever heard before!

    3. Drums sound inferior on the PDM 1 Series 3 unit, they lack the 'slam' that the Little Bit II has.

    4. There is a slight crackle when the units are powered on via the rocker switches on the back. Not really an issue as I usually leave them turned on.

    5. If the DACs are on, turning the tone controls on and off on my preamp (Audiolab 8000C) introduces a nasty spike through the speakers. This has never been noticed by me before, I don't really use the tone controls to be honest. I was only playing around with it because the PDM 1 Series 3's sound was a bit bass light compared to the Little Bit II.

    6. In what I consider very odd, the PDM 1 Series 3 DAC has less rhythm/pace than the Little Bit II, but is still very musical. It just seems a bit slower than the Little Bit II. My foot taps quite happily :)

    7. I've noticed on several recordings that I know well, that vocals seem to lack emotion, when compared to the Little Bit II.

    Said lady of the house (with very keen hearing) described the sound as thinner and brighter and lacking in bass. She prefers the Little Bit II. I'm wondering a couple of things...

    Note: unit sounds better via headphones (Sennheiser HD420 Gold References), some of the issues like midrange/vocals/sibilance disappeared on the same recordings that had issues.

    a) Could the AC mains in Australia have anything to do with it? We use 240v 50hz, I know the UK uses 240v, but I'm not sure on the hertz rating. Is this different, and if so, could this create issues. If so, is it easy to fix? I have no technical knowledge/electronics and in all honesty, wouldn't pick it up.

    b) The crackling noise when turning the DAC on, or with the tone control on the preamp - is that a sign of possible issues to come? I notice no hiss or crackling from the speakers whilst playing.

    c) Interconnects - I'm using the coax cable that came with the Little Bit II to connect to the transport, so I presume that that's OK. I'm using some el cheapo silver plated interconnects to the pre amp, I've never noticed any brightness or issues with them before, could the DPA PDM 1 Series 3 DAC have issues with the brightness of silver interconnects? I have a spare DNM Reson interconnect that I can use if need be. If I remember, DAC 7 DACs were considered to be a bit brighter sounding than the SA7350 chipsets...

    d) CD transport - In lieu of my Teac Esoteric P-500 unit malfunctioning, I've been using a Pioneer DV-344 DVD player as the transport (loaned kindly to me by a mate, otherwise I'd have no CD source at all). Could a cheapish DVD player like this not be good enough for the PDM 1 Series 3? Was never any issue with the Little Bit II, so I'd find it odd...

    e) Do you have any circuit diagrams/user guides that you could email me/send me? I'm only happy to pay for costs involved etc (would be by Paypal as I don't have a credit card).

    f) Upgrades/deltran - what are your thoughts on this? I wouldn't be able to afford any upgrades to the PDM 1 Series 3 (if that's possible) for several months. Also, is deltran'ing a unit really worth it? Does it really make that much of a difference? Are parts still available, and is it that hard to do? To send it to the UK would be dangerous (possibly damaging the transport en route) and costly. I believe Chevin Audio can help here, first I'd have to get the Teac fixed (it's been unused for 4 years, probably a dead laser). I guess, if I could get the deltran parts/instructions, I could get a local electrical engineer to do it for me, in lieu of my skills in the area. That would save a fair bit of money of course in shipping costs.

    I paid quite a fair bit of money for the PDM 1 Series 3, and I'd be saddened to have bought a lemon with issues etc. Yes, I know buying units 2nd hand, across the Internet is frought with danger, caveat emptor etc. DPA units seem to be very hard to find, and fetch good prices (I paid 400 pounds 2nd hand for my unit from EBay UK).

    Sorry for the long PM, any advice or help would be really appreciated.



    PS I'm keeping the Little Bit II!!! Any advice on leaving it unpowered for long periods? My logic tells me to plug it into power every month or so to have an electrical current running through the unit. "
  8. EJB

    EJB pfm Member

    Three years and this thread is still going:cool:
  9. tumbleweed

    tumbleweed Member

    Three years on and this brand new member is going to push it forward a little more into the future.

    I have a DPA T1, an old friend now, which stopped playing while I was out of the room. When I went to see what had happened there was smoke and a disgusting smell of electronics in crisis.

    I can safely say that I know nothing about the inner workings of things like this but I took the cover off to see if I could see anything obvious. On the outside of the casing around the power socket was a sticky resinous substance but inside I could see nothing untoward at all. So I carefully cleaned up the case with white spirit and considered my next step.

    Turn it on I thought.

    Sooooo... I plugged it in to an extension, settled myself a safe distance away and flicked the switch on the extension.

    Whooooosh! It was as if the power socket had become an aerosol - it squirted a fine mist of yucky stuff under very high pressure through the edges of the socket and... oh the smell :mad:. I switched off after about one second and saw that more residue had oozed out and was starting to run down the casing. Cleaning time again.

    Any advice about this will be hugely appreciated. The small unit attached to the back of the power socket... is this likely to be the power supply? It is definitely where the spray is coming from. If so then maybe I just need to replace it if I can find somebody that has one.

    Tom perhaps, if he's still around?

    Shiny case - sticker on back - serial number 92120108

    Many thanks to anybody kind enough to spare the time to offer some wisdom :)
  10. martin clark

    martin clark pinko bodger

    Something has let go in the PSU/ input, probably a capacitor, and so it should be quite a straightforward repair, not necessarily a unit-killing episode. Any chance of a pic?

    If you're anywhere near Bath I'll be happy to take a look if that's any help.
  11. tumbleweed

    tumbleweed Member

    Thanks a lot for replying.

    I live at the tip of the Wirral peninsula in Merseyside so not so close, but then again not so far either.

    Here are a couple of poor phone pics which I hope will suffice:


  12. martin clark

    martin clark pinko bodger

    Ok then - something has let go inside the mains input filter block.

    This is good news - it isn't a proprietary part but one of the generics (Corcom, Schaffner etc) so you can simply swap it for a similar pattern part (e.g. from RS, Farnell, CPC or Rapid Electronics - amngst others) or replace with a regular unfiltered IEC input socket, such as your local Maplin might do.

    If you don't want to wield a soldering iron yourself it's the kind of small task any TV/Radio repair place can do for you. Also within a reasonable distance (Derbyshire) is Colin Yallop of Chevin Audio, who has a lot of experience with Deltec/DPA kit.

    Hope you get it fixed :)
  13. tumbleweed

    tumbleweed Member

    Great - I'm a dab hand with a soldering iron if I think I know what I'm supposed to do with it lol, so replacing an identical component should be no problem.

    I'll whip it out tomorrow and hopefully there will be some identifying marks so I can track one down from the outlets you suggested.

    Thank you very much for your help... you're a star!


    DPA_SERVICE Active Member

    Alternatively, you could just swap it out for a standard chassis mounting IEC socket for a lot less. The mains filter is bog standard, nothing special, if it was so special how is it Watts never fitted in what followed?

    Better you use " The Power " RF mains filter, they sell on Ebay for not a lot.
  15. tumbleweed

    tumbleweed Member

    Thank you also DPA_SERVICE - advice much appreciated :)
  16. tumbleweed

    tumbleweed Member

    Great news - replaced filter socket with a standard one and it's all working fine again - so martin clark and DPA_SERVICE... thank you both so much for your help and advice.

  17. martin clark

    martin clark pinko bodger

    Well done! I hope it brings many more years of enjoyment.
  18. jwdude

    jwdude Active Member

    I have a DPA PDM ONE series 2 for sale - check classifieds if interested...
  19. UKSwede

    UKSwede pfm Member

    If you are using the DPA T1 as a transport without using the deltran interface eg to another non DPA DAC, you could Trichord Clock the DPA T1. Not so expenisive I did this to my unit with great improvement. My DAC is the MSB Platinum


  20. tomek

    tomek pfm Member

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