Adventures with a Soldering Iron Part 2 (DAC Build)

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Comments

  • Indeed. Hifi taking a back seat while I spend a fourth night in Hosptial. On a plus note I need two weeks complete rest which sounds like a good excuse for a DAC comparison.
  • That sounds like a definite upside, James :-D
  • Hope your OK James
  • This morning I've been comparing my two DAC's now that my speakers are starting to break in. It's clear to my ears that the DDDAC is superior. This DAC presents music in a way that makes the PS Audio DAC sound slightly flat in comparison. I still think it's a very good DAC, just not as good as the DDDAC. I'm going to replace the output caps with transformers now to see what difference this makes.
  • Hi Jim, hope Bones did a good job stitching you up. He's good so long as he leaves the Romulan ale alone.

    Those solder burns can be nasty, did you need an ambulance?

    LLaP,

    A
  • Hi Jim, hope Bones did a good job stitching you up. He's good so long as he leaves the Romulan ale alone.

    Those solder burns can be nasty, did you need an ambulance?

    LLaP,

    A
    Hi Alan. No ambulance required, but Bones has done a poor job of stitching me up. You know that scene from Alien where it escapes through someone's tummy? That's what mine looks like.....only worse! @-)
  • Oh dear. Maybe you need a young Sigourney Weaver to make it better ;-)
  • I'll settle for Mila Cunis :x
  • Sounding promising James
  • Any more updates Jimbo?
  • Output transformers fitted now James which has yielded further improvements. I've broken one of my power amps at the moment so only listening in mono! Still sounds great.

    I've still got to fit the shunt regs, but I might wait and buy a second DAC board and another set of shunt regs. There's a lot of desoldering/soldering to do with both the shunt regs and the second DAC board, so it makes sense to do it all at once.

    The cost/performance ratio is remarkable with this DAC. For £400 or thereabouts it's a no brainer.
  • Do you know of anyone round kent with one?
    Would love to compare with my MDAC?
    My hunch is that is is better, but it's a big leap to take not knowing.
  • I'm not aware of anyone with a DDDAC in Kent.  As good as the MDAC is reputed to be, I can't see it being better than the DDDAC, not judging by the long list of high end DAC's that are being replaced with the DDDAC. 

    Best to ask on DIYaudio as there are several UK users and there's bound to be someone near to you. Alternatively, you are welcome to bring your MDAC up to me for comparison (I appreciate that's a long trip!).
  • I'm not aware of anyone with a DDDAC in Kent.  As good as the MDAC is reputed to be, I can't see it being better than the DDDAC, not judging by the long list of high end DAC's that are being replaced with the DDDAC. 

    Best to ask on DIYaudio as there are several UK users and there's bound to be someone near to you. Alternatively, you are welcome to bring your MDAC up to me for comparison (I appreciate that's a long trip!).
    But then I read comments like this 
    "Not only have I tried it but I've tried the mdac vs the Weiss 202 DAC and into and against the Naim nac72, the Tom Evans Vibe, Puresound L10, Krell ksp 7b and the XTC Pre1 all over the same weekend. The Weiss was a touch better than the stock Mdac"
    And I wonder, I really need to hear it to be sure.

  • How are you doing James with your new DAC and speakers?
  • Hi James.  There's no much listening happening at the moment, because I damaged one of my amp modules trying to remove a resistor.  I sent it back to Hypex but it doesn't seem to have arrived :-(.  Looks like I will need to open a claim to get my money back.


  • Oh bugger. That's a pain.
  • What a pain, who was the courior ?
  • Parcelfarce.
  • My DAC lives again :-)

    It is now sporting shunt regulators from Tentlabs.  My end goal is to have two stacked DAC boards, both with shunt regs.  Given I haven't tried de-soldering before I thought it safer to remove the standard regulators from my new DAC board, rather than have to work around the other fully soldered board.

    There are four regulators on each board.  Two 3.3v and two 8v.  Below you can see two of the exposed pads before I desoldered them.  I broke the pins off rather than risk lifting the two small pads on each reg that I wanted to solder the new shunts on to.





    image

    Here's a pic of the board with all four regs removed:

    image

    First two shunt regs soldered.....

    image

    Always a relief when a change like this doesn't result in a puff of smoke.......

    image

    This last pic also shows the output transformers.  Their circumference is slightly larger than a two pence piece.  As this is a new DAC board I need to give it time to break in before determining what effect on sound quality the shunt regs have had.  I also need to trace the cause of a slight hum that has appeared since the output transformers were installed - it is volume dependent and I think caused by a grounding issue somewhere.

    Next step will be to remove the shunts and solder wire to each of the three legs, so that I can lie the shunts on their side and mount a second DAC board on top  :D
  • That looks scary James.

    Thanks for posting.
  • Nice one James , I'm following this thread with interest.
    Thanks for the update
  • What is the latest here James?
  • No update at the moment.  I still intend to add another board with shunt regs but currently in a quandary about how to feed the Wave IO USB board.  The software I run on my Alix board doesn't support Spotify so I'm pondering the following options:

    1)   Install Ubuntu and Squeezelite on the CF card I use with the Alix board.  Not sure my Linux skills are up to doing this.

    2)   Use a wand board in place of the Alix board for which there is a ready to go Linux/Squeezelite image available.  Even my Linux skills could install this.  Downside is I would need to find a new power supply to go in the box because the PS board I use for the Alix is 1A max.  The wand board needs a 5v/2A supply. 

    3) Ditch the integrated streamer concept and buy a SB Touch, install EDO and use the USB output.


    I'd really like to keep the streamer inside the box so option 2 is looking favourable providing I can find a power supply board for it.
  • Thanks for the update James.
    Have you had a chance to draw any conclusions as a stand alone DAC , especially in respect to your previous DAC?
  • Yes.  This is quite easy to do because I can use the USB input on both DAC's.  My preference is for the DDDAC.  It sounds more natural to my ears.
  • Nice work James, very impressive effort. It certainly takes some commitment & bravery on your part!

    What exactly are the output transformer likely to add over the standard output?
  • Hi Alan.  The output transformers sound more immediate/faster than the Mundorf caps. Here's an updated picture of my DAC which now has two boards both equipped with improved regulators:

    image

    It's fair to say there is room for improvement in terms of wiring layout :)).

    Adding a second board over the existing one was a slow process.  I had to add wire extensions to each of the regulator pins.   My first attempt at powering up this latest build resulted in the power supply fuse blowing, so I had to disassemble it and start again, checking at each stage that it powered up correctly.  There must have been a bad solder joint because it fired up fine the second time round.

    I've also changed the stock dale resistors for carbon film items.  The Audio Note tantalum resistors I have will require the mounting holes to be drilled out ever so slightly.  I'll let the new board and resistors break in before getting a drill out :-SS

    Final stage is to find a suitable enclosure. 
  • Thanks for the update James, how would you say the sound of the DAC has changed with the further modifications?
  • It's a substantial piece of kit.
    Must've been pleasing to rectify the solder joint. :-)

    Can I recommend a hand drill...? :-/
  • Thanks for the update James, how would you say the sound of the DAC has changed with the further modifications?
    Hi James. It's too early to say at the moment. The DAC has only been on for a couple of hours. I'll give it around 50 hours to break in.

  • It's a substantial piece of kit.
    Must've been pleasing to rectify the solder joint. :-)

    Can I recommend a hand drill...? :-/
    So you don't think my power drill with masonry bit is suitable? :-B
  • Not on hammer mode, no. :-(
  • Is anyone able to help here, I am selling my MDAC to finance the dddac
    I currently use the MDAC straight into my power amp, the MDAC has a remote volume control which I use regularly.
    My question is
    A) can I run the dddac straight to my power amp
    B) is there some software that will control the volume or do I need some sort of remote control pre amp?

    Thanks
  • You can use software James, e.g. audirvana or JRiver but if it crashes for whatever reason and happens to send full power through your speakers..... :-O
  • Been there. Done it. Fried speakers.

    Don't rely on software.
  • Ok thanks for the advice.
    I'm trying to spend money on the DAC and not on a pre amp, what would be the best and cheapest pre amp. I really want a remote or the ability to amend volume from software without frying amp or speakers. Can anyone advise a good way forward ?
  • You could set the Alsamixer (part of the Linux software installed on the USB board) gain values to be a lower value, so that if the software did fail, your speakers would be limited in volume by the Alsamixer settings. Again though, the alsamixer is software but it at least provides a safety net.

    I'll have a think about simple preamps. A volume pot in a box should not prove very expensive to get you going.
  • Wow that is cheap and looks great
  • Tisbury one with the stepped attenuator looks incredible value on the face of it. No idea how different stepped attenuators compare, but the change to stepped attenuators in my NVA P90 made a real difference (that costs £640 new, tho is dual mono).
  • edited March 2016
    Been a while since i updated this thread.  Here is my DAC now: 

    image

    As you can see, it has changed rather a lot :-B.  I'm now using an output buffer (top left of shot) which drives the Cinemag transformers much better. It was a pain to install due to a) lot of SMD soldering and b) it needs a +12v and -12v supply which meant a second power supply was required.  The small r-core transformer powers the -12v supply for the buffer and +6v for the beaglebone black (bottom left of shot).

    The boards that connect the beaglebone to the DAC are from Twisted Pear Audio.  They contain two high quality crystek clocks and isolation between the computer and DAC.  I use small ufl connectors to take the I2S feed from the Twisted Pear board onto the DAC main board.

    This morning I've added charcroft z-foil resistors to the RCA sockets to hit the 100k Ohm input on my amp. They sound cleaner than the Audio Note non-magnetic resistors I was using previously.

    Note the high tech transformer mounting system - shortly to be replaced with cap mounting clips.

    All I've got left to do is 

    1) Replace the back panel with a better quality IEC inlet and some foo rca sockets.
    2)  Tidy up the switch and SPDIF white wires which you can see hanging over the DAC board.
  • Well done, I love the C Core transformers, what ratio are the audio transformer in the sheilded cans?
  • AntiCrap said:
    Well done, I love the C Core transformers, what ratio are the audio transformer in the sheilded cans?
    1:1 ratio:

  • edited March 2016
    That's a DAC...?
    Very impressive. It's got more circuitry in it than my entire setup put together!
    How's it sounding...?
  • Yeah, it looks well cool.
  • Part of it is a DAC. Most of the items you can see are for various power supplies.

    I'm really happy with how it sounds. Before I made the last set of mods it was sounding more natural than DAC's like the Auralic Vega. I'm hoping to compare it to a Meitner MA1 in the near future.

    The big plus is that I can run Squeezelite software to access my NAS plus Spotify and Tidal all from an app on my phone.
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