It's called "Vintage", so your DAC goes with your threadbare tshirt and $250 ripped jeans.

  Might be wrong, but I think it's Hammond.

  I'd look at getting some solder wick and getting rid of the extra solder on the crystal oscillator. I had problems on my pupdac with too much solder on the oscillator shorting against the case (was so small I didn't notice it initially). USB hubs will disable devices if they draw too much...

  My interpretation was that the micas were part of a low-pass filter on the differential pair coming from the DAC, since the opamp has bandwidth well above audio frequencies... I'll defer to the actual designer though :)

  I stood at my workbench last night for two hours going through all the tracks that I gravitate towards when testing audio - it was hard to turn everything off and go to bed... I'm not unhappy at all for having to swap out the opamp - thank you for including both in the kit! As for power &...

  I checked the resistors and they were all in the right place. (I was being super meticulous, so it was a bit worrying to think that I'd maybe messed that up). I measured a bunch of point to point resistances around the opamp and they all summed to expected values. In the end I cut out the...

  hmmm... I was wondering if it was maybe a resistor mix-up. Both signals out of the opamp are very stable non-rail voltages. I'll check that when I get home. FWIW I installed the OPA2835 first - I'll swap with the OPA2836 if the resistors don't show up anything.   This project hasn't been my...

I put together my pupdac today, but it hasn't gone particularly smoothly... It recognises in Windows, all voltage test points pass, but I'm getting a very large offset of -0.5V on the left channel and -2.4V on the right. Hooking up the scope shows some audio signal, but at a very low level. I'm...

Excellent... gives me time to move into the massive money-pit my new house and set up a decent workbench for electronics.

If you are hand-soldering the GrubDAC, try approaching the pins end-on with a very small amount of solder. I broke a kit on my first attempt by being a bit sloppy. Some of the vias will punish you with bridges.

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...

Quote:   Looks nice! Are you using the perfboard to adapt the grubdac board to slots in the case?

No worries... a fresh set of eyes always helps!

Nice photos!   Is that a solder bridge on the top left of U1? One of the mini-USB pins looks like it might be a cold joint. 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...

Here is the circuit I drew for the battery meter. Like I said, if I was doing this again I'd add a resistor in series with the scale set trimpot (on the V+ side) in order to make the pot range more useful. Both pots are (I think) 50k linear, R2 (LED brightness) is 2.7k, LED power bypass is...

Yeah, the "lack of bass" might be that. Those specific headphones are marketed as flat-response phones for mixing and production work, so it's not surprising they don't have the subwoofer-on-your-head marketing many other headphones have.   I do have a couple of Burr-Brown OPA2132PA opamps...

Here's my completed PIMETAv2+GrubDAC amp:   (Fullsize images also here: amp exterior and interior)   Details: PIMETAv2 using AD8620/8610 opamps. Everything's pretty standard. Power supply is 10 x NiMH AAA cells, for a nominal supply voltage of 12V. Input is a GrubDAC...

Tried to build my GrubDAC last night, but had a unseen bridge on U1 that shorted VDD to ground. (LED lit but flickering, 10mV on 3.3V test point, no USB detection, one very hot inductor). Fixed that, but now it's doing the "USB device unrecognised" thing. I'll give it another once-over tonight...

Look, all you have to do is find an old pick-and-place machine and put a bag in place of the board. Problem solved! 

Quote: I am totally in for a kit if/when they're up on Beezar! (Got a grub on the way, but would upgrade to a pup)  

Yeah, I suppose I could have done that, but I've already pulled the trigger on a new DAC kit  In any case, a new PCM2702 from RS is around 60% of the cost of a whole new kit and would be a couple of weeks away if it came from the UK. Next order I make with RS I might get one and try to repair...

  Quote: Yeah, I think the PIMETA is blameless in this, but thanks heaps for taking the time to check it out... Unfortunately I don't have access to reflow gear (and no spare toaster ovens), so it's easier to just chalk it up to experience and buy a new DAC kit.   The batteries I...

There have been a few reports of people frying one or both channels on their Alien DACs, eg: here. Possibly if the PCM2702 outputs see an unexpected transient, which I may well have done while disconnecting the scope probe.   More pictures   Top pic is a post-build, pre-clean shot of the...

  Quote: Here's a few pictures: http://imgur.com/a/ZUpw0   The noise on the DAC outputs looks the same when isolated from the amp. I set up a resistive voltage divider on a breadboard to simulate the ground level. When that was noisy I tried a TLE2426, same result.   Noise on...

Quote: Apologies for the ugly visio diagram - I'm still at work and it's all I have... Fullsize image   So in summary:   The Alien DAC design includes an option for powering from a virtual-ground amp. This uses a BUF634 to pass & isolate the ground level from the amp. The...