[dBel84]

I haven't stuffed my board yet - ended up going to the Bay area meet which was just magnificent. Planning on getting it done in the next day or so , looking forward to seeing how this impacts the O2. 
 
and thanks for the xtra bits TomB - I didn't even think to check ( which is a major fail on my part - this is how we catch tired brain phenomenon ) 

 

[tomb]

You're welcome, dBel!
 
OK - everyone's parts were shipped this morning:

1. The correct right-angle USB - A jack
2. L1, L2, L3, L4 - properly rated
3. C8
4. R5

 

[tomb]

I replaced the connector on mine and it works flawlessly!

 

[Avro_Arrow]

  I replaced the connector on mine and it works flawlessly!

Good to hear Tom!
 
Now you can torture it...

 

[Ikarios]

Checking in with interest here. Any possibility on getting this integrated with the pupDAC at any point in the future? Looks lovely.

 

[muskyhuntr]

Welp, finished populating my board.  Had absolutely no problems working on the digital side.  Even J1 went in/on without a hitch. The good news is that it fired up first time.  Plugging just the Doodlebug into my computer yielded nothing, as it should.  Next, plugged in my Y1  and  it's power LED lit (a red toggle switch).  Finally ran some tunes through JRiver.  Indicator went to green!  I used a Mini3 and my Senn HD600s for listening tests. 
 
How did it sound?  In a word, better.  I use the Mini3/Y1 combo quire a bit so I am familiar with its signature.  The most predominate thing I noticed was an increase in clarity followed by a slight improvement in bass.  I am not talking leaps and bounds here, but definitely a notch better. 
 
A few pages back, I made some suggestions for the power supply portion of the board, I still think they warrant a look (esp. an aux.  5V output jack.  I think that it would make the device a bit more useful).  Other than J1, I think the digital side of the board is right on.
 
I do have some bad news, but it too is followed by some good news.  For the life of me, I could not find the caps I ordered for C1.  So I did my testing without it.  The good news is that it worked flawlessly without it.  It gets populated on my next order.
 
One question, will this board fit into the cases you plan to offer?
 
Thanks for the opportunity,
Jim

 

[tomb]

  Welp, finished populating my board.  Had absolutely no problems working on the digital side.  Even J1 went in/on without a hitch. The good news is that it fired up first time.  Plugging just the Doodlebug into my computer yielded nothing, as it should.  Next, plugged in my Y1  and  it's power LED lit (a red toggle switch).  Finally ran some tunes through JRiver.  Indicator went to green!  I used a Mini3 and my Senn HD600s for listening tests. 
 
How did it sound?  In a word, better.  I use the Mini3/Y1 combo quire a bit so I am familiar with its signature.  The most predominate thing I noticed was an increase in clarity followed by a slight improvement in bass.  I am not talking leaps and bounds here, but definitely a notch better. 
 
A few pages back, I made some suggestions for the power supply portion of the board, I still think they warrant a look (esp. an aux.  5V output jack.  I think that it would make the device a bit more useful).  Other than J1, I think the digital side of the board is right on.
 
I do have some bad news, but it too is followed by some good news.  For the life of me, I could not find the caps I ordered for C1.  So I did my testing without it.  The good news is that it worked flawlessly without it.  It gets populated on my next order.
 
One question, will this board fit into the cases you plan to offer?
 
Thanks for the opportunity,
Jim

Sounds great!
 
Yes, I don't think Avro has changed anything from the standpoint of the connectors with regard to case-fit.  That's what would make a difference with a custom case.  It should stand as the guide for the case-design, as is.  You'll have to file that sprue left from breaking the boards apart, but other than that, it shouldn't change.
 
I'll be drawing up the case design in the next couple of weeks, so maybe I'll have something more definite to show.

 

[tomb]

  Checking in with interest here. Any possibility on getting this integrated with the pupDAC at any point in the future? Looks lovely.

Sorry, but I don't think we have any intent to make something like a 2-PCB integration in the same case.  If it's possible as is, then go for it.  However, the DoodleBug is a complete device on its own and while my personal choice is always pairing it with a PupDAC

 , I think we want the applicability to be as wide as possible (ODAC, GrubDAC, SkeletonDAC, Y1, etc.).  It's very easy to plug into an existing arrangement with the PupDAC and other USB-powered DACs with only one extra mini-USB cable.
 
If possible, I'll try to locate the mini-USB cables that are only an inch or two long, so that the arrangement with a PupDAC could resemble the short interconnects that people use with portable iPod/amplifier connections.  I have one that came with a Seagate portable drive, so maybe they're mass-produced somewhere and available for purchase.

 

[JacobLee89]

 
If possible, I'll try to locate the mini-USB cables that are only an inch or two long, so that the arrangement with a PupDAC could resemble the short interconnects that people use with portable iPod/amplifier connections.  I have one that came with a Seagate portable drive, so maybe they're mass-produced somewhere and available for purchase.

 
There's always the fun of DIY'ing USB cables 

 
Just imagine a project called " STUBBY USB CABLE! "

 

[Mullet]

This project looks super cool. I'll probably build one for my PupDAC. I recently built a DAC that employs USB isolation and it sounds great. A few questions...
 
1) Is there a possibility of using external battery power with this? If so, what would be required?
 
2) This one might not be able to be answered yet... For the guys who use a Gamma 1/2 is there a benefit to this being that it already has the option for an external 5v supply?

 

[DingoSmuggler]

  This project looks super cool. I'll probably build one for my PupDAC. I recently built a DAC that employs USB isolation and it sounds great. A few questions...
 
1) Is there a possibility of using external battery power with this? If so, what would be required?
 
2) This one might not be able to be answered yet... For the guys who use a Gamma 1/2 is there a benefit to this being that it already has the option for an external 5v supply?

1. Sure, you'd need a battery capable of maintaining over 9V at whatever current your USB load is going to draw, for however long to want it to work - so likely something fairly hefty.
The power supply on the doodlebug in it's current form won't be overly efficient for battery use. It will draw 10-20mA or so through the LEDs depending on the exact devices and where you set the output voltage. But with some component changes you could get this down to 1-2mA at the expense of possibly raising the noise floor a tiny amount.
 
2. It depends on whether or not an isolated ground will give any rewards. Some computers (especially laptops) have noisy ground rails and this will get into the analog output of your DAC if it has the digital and analog grounds connected. If there isn't a problem with a noisy ground, or ground loop(s), then a full USB isolator shouldn't offer any benefit compared to power only, everything else being equal.

 

[Avro_Arrow]

Thank you everyone who have provided your valuable comments so far.
 
 
The intent of the isolator is to: 
1. Break any ground loop to reduce noise.
2. Provide ample, quiet power.
 
The isolator will not guarantee an audible improvement in all situations.
However, in situations where a USB DAC is struggling, it can provide
a dramatic improvement.
 
It can be run from a battery, however it was never designed to be
power efficient. A 7.2 vdc battery would work if the bridge rectifier
is not used, a 9.6 to 12 volt battery would be needed if the bridge
rectifier is left in place. You would want at least a 2 A/H battery
capacity to get reasonable run time.
 
While adding a DC output jack may seem like a value add, I feel
it may cause confusion with some user and could result in equipment
damage. For those who wish to hack, 5 vdc is conveniently available
from the test points on the board. This also bypasses the 500mA
fuse.
 
The two LED's are used to set the output voltage and give the
design very low noise compared to other LM317 designs.
It should be possible to use one as a power indicator, but
this has not been tested and the extra lead length may lead
to unpredictable results. Again, a power LED could be added
at the test points if two LED's inside the case are not enough.

 

[TheShaman]

  It should be possible to use one as a power indicator, but
this has not been tested and the extra lead length may lead
to unpredictable results.

One can easily get cheap fibers from eBay or elsewhere; they can be used to transfer the LED's light to the front panel. I use this method extensively in my builds.
Much easier than messing with wires etc and can be tweaked to get the brightness you want without having to adjust current.
 

 

[Avro_Arrow]

 
One can easily cheap fibers from eBay or elsewhere; they can be used to transfer the LED's light to the front panel. I use this method extensively in my builds.
Much easier than messing with wires etc and can be tweaked to get the brightness you want without having to adjust current.
 
 

Excellent idea

 

[fishski13]

i dusted off my y2 and found that the USB is a bit flaky sans Doodlebug - one of my first SMD builds from years ago.  i'm ordering a new PCM2707, but no guarantees this will be the fix.  i'm borrowing an ODAC that should be here by Fri and i will be able to report back with impressions this weekend.