The GrubDAC
Apr 10, 2012 at 10:03 PM Post #886 of 1,079


Quote:
Finished my GrubDAC yesterday (built in in a couple of lunch breaks on my bench at work, where I have proper tools, magnification, etc.). Did a basic test at work (everything worked fine), and brought it home last night. Fired up the laptop and was able to access my music files on my desktop PC. Piped through my recently completed MiniMAX, the sound was excellent. (Lossless flac --> laptop --> GrubDAC --> MiniMAX --> Denon AH-D5000)
 
So far, I am very impressed with the GrubDAC. The music was presented very cleanly, with good soundstage and imaging. Bass was solid, and highs were clear and sparkling without being shrill or harsh. I think it sounds better than my iMod, based on a fairly short listen. I'll do some more listening and get some burn-in time on the DAC. I will likely use my iMod as my main work/portable source and use the DAC at home.
 

Fantastic!  Glad it went well.
biggrin.gif


 
 
 
Apr 16, 2012 at 12:31 AM Post #887 of 1,079
Just finished my GrubDAC build (cableDAC config).  Found out that I'm not all that great at surface mount soldering but still somehow got the DAC working.  Used lots of solder wick to clean up the messes I kept making.
 

Went with rubber grommet and a regular black case. 

Many thanks to TomB and cobaltmute for all the work that went into the design and putting the kits out.
 
May 10, 2012 at 7:58 PM Post #888 of 1,079
    This seems to be the main GrubDAC thread so I'll post my woes here. I recently finished a Millet Mosfet Max build thanks to the help of a few Head-fi members/mentors (check this thread out if you're having any issues: http://www.head-fi.org/t/604880/having-an-issue-with-a-mosfet-max-build). In addition to this, my third or fourth endeavour into DIY audio, I started a GrubDAC build. Despite the fact that I've never delved into SMD before I feel that the end result is halfway decent.... looking...
    My issue is this: 1) Both of my computers recognize the DAC as "USB audio DAC" or something to that effect. 2) The LED lights up as it should. 3) The only way I've tested this so far is to plug it into the punch down block inputs of the MAX and see what happens. I also tried threading the outputs of the DAC into the extra pot pads with the same result. Humming... No music just a humming noise from my headphones.
    I have a few pics that I hope will help you guys help me and I can take plenty more if needed. As I stated in my mosfet max build thread, I'm not an electrical engineer but I'm pretty good at problem solving/understanding things as long as it's in laymans terms. Without further ranting and getting to the point, here's some pics and thanks in advance for any help given:

 
May 10, 2012 at 8:09 PM Post #889 of 1,079
Nice photos!
 
  1. Is that a solder bridge on the top left of U1?
  2. One of the mini-USB pins looks like it might be a cold joint.
  3. I'd also check the right hand side of the top row of DAC pins in case there's stuff in there causing problems.
 
I hope you get it going - I destroyed one on my first attempt, but the second one works a treat.
 
May 10, 2012 at 8:56 PM Post #890 of 1,079
Reflowed all mini-USB pins, cleaned, checked - no go
 
Cleaned all extraneous stuff between all pins (was Q-tip fuzzies from prior cleaning lol), checked - no go
 
Tried desoldering possible solder bridge between pins 1 & 2 on the left row top side, solder refused to lift no matter the amount of flux or patience applied so VERY CAREFULLY took an X-Acto knife and scratched the bridge away....
 
Thank you Geofftnz, this freaking little bridge has been p-ing me off and holding me up from ordering the remainder of items necessary to case up my Millet MOSFET Max build that a few other Head-Fier extraordinaires coached me through. I actually have half a mind to order another one just cause that little sctratch in the PCB is gonna get to me even though I can't see it lol.
 
Sounds awesome so far by the way, I've been running through a uDac2 as my source until now and I can't say it's a slouch, it's a very "fun" DAC but I"m going to spend some time switching between the two this weekend and taking (objective) notes to post up on here.
 
Thanks again, I'm a little peeved that I missed that but I'm glad you picked up on it.
 
-Chris
 
May 10, 2012 at 9:09 PM Post #892 of 1,079
Oh and thank you for the compliment on the pics. Just FYI for all the readers my photo setup is nothing more than a point and shoot digital cam (Sony DSC-H3) on a baby tripod in macro mode. I held an LED flashlight behind the GrubDAC to emphasize the soldering, put the camera on a 10 second timer, focused and shot. Just a hint: In macro mode, keep the object close, don't place it at a distance and attempt to zoom because the camera will not focus....
 
May 19, 2012 at 12:04 AM Post #893 of 1,079
Finished off my first GrubDAC. Started up just fine. It was a fairly easy build with the exception of dealing with smd caps and resistors that didn't want to stay stiill. I went with the Hammond 1455C801 case and scored some Front Panel Express files from Beftus, which I then slightly modified to my liking. I then air wired the led and 1/8" jack. The trick to getting the board to stay stationary was to buy some perf board at the good old RatShack, which I then scored with an exacto knife to match the needed size. I then broke the piece off and sanded the edges to get a perfect fit. Here are a few pics...
 
As far as the sound quality, I'd say this DAC is on par with a Gamma-1. They seem to have similar presentation and a lively feel. For the money, even with spendy FPE panels, you can't go wrong.
 

 
May 19, 2012 at 12:16 AM Post #894 of 1,079
Quote:
The trick to getting the board to stay stationary was to buy some perf board at the good old RatShack, which I then scored with an exacto knife to match the needed size. I then broke the piece off and sanded the edges to get a perfect fit. 
 

 
Looks nice! Are you using the perfboard to adapt the grubdac board to slots in the case?
 
May 19, 2012 at 12:21 AM Post #895 of 1,079
Yup. That's exactly what I did. It's the best way to do it other than using something like these... http://bit.ly/LlR57A
 
May 19, 2012 at 12:30 AM Post #896 of 1,079
Yeah, I've just done a grubdac+PIMETA2 build in a slightly large Hammond case. I used 10mm hex spacers to mount the boards, however without a high-speed drillpress it's very hard to drill the holes exactly where you need them, even when using a centre-punch. Consequently the amp board has only 2 screws.
 
Next time I'll use your perfboard trick.
 
May 19, 2012 at 12:41 AM Post #897 of 1,079
Those stand-offs I linked to have adhesive on the bottom. I'd imagine if they were too big you snip some of the plastic off to make it fit in that Hammond case.
 
I don't have a high-speed drillpress at my disposal and I'm about to embark on a journey building both "The Wire" and an EHHA Rev A not long after. I'm nervous about drilling the proper holes without the right tools, so I think those self-adhesive stand-offs are going to be clutch.
 
Jun 25, 2012 at 10:11 AM Post #899 of 1,079
Is it possible to make a grubDAC minus the 2706 and feed an i2s signal directly to the WM8524? Would I just leave off parts of the build, or would it require a redesign?  Also, would i2s off a small ARM computer be a sonic problem, or would it be fine since it's still digital at that point?
 
Jun 25, 2012 at 10:51 AM Post #900 of 1,079
Is it possible to make a grubDAC minus the 2706 and feed an i2s signal directly to the WM8524? Would I just leave off parts of the build, or would it require a redesign?  Also, would i2s off a small ARM computer be a sonic problem, or would it be fine since it's still digital at that point?


It could be possible. You'd need to feed 5V power to the board and then solder wires to the appropriate pads.

Not something I would want to do, but it is possible.
 

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