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The GrubDAC - Page 6

post #76 of 952
10/1/09 at 3:50pm
Thread Starter 
There is still a bunch of boards available if some are interested.

On a different note, PCM2706/7 seem to be in short supply. Digikey's shipping date has slipped to Oct 12 on the PCM2707. Mouser is slipping their dates as well.
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post #77 of 952
10/1/09 at 5:29pm
If you're really desperate, you could probably grab some from amb. Think you'd need to stock up some PCMs to match the number of boards you ship? Same way amb does it.
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post #78 of 952
10/1/09 at 8:03pm
Thread Starter 
Quote:
Originally Posted by joneeboi View Post
If you're really desperate, you could probably grab some from amb. Think you'd need to stock up some PCMs to match the number of boards you ship? Same way amb does it.
Personally, I'm not desperate, just letting people know.

It is also a big jump from selling a few boards to having to ship static sensitive devices. And if I was to handle parts I'd go the whole way and deal with kits.
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post #79 of 952
10/1/09 at 9:17pm
I ran across some more good USB design info at
http://rfdesign.com/next_generation_...le_2_Final.pdf
Check out the physical layout recommendations. Just something to think about if/when you do another set of boards.

Also when tying pins high or low, use a trace to a set of smt resistor pads with a trace between them, so you can cut the trace to disconnect the pin and later use a smt resistor to reconnect the pin again. Also bring all unused pins out to a pad or via.

Pin >---[pad]--x--[pad]--gnd or Vcc (cut at x to disconnect pin)
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post #80 of 952
10/1/09 at 9:53pm
Wouldn't ya know! I went to order my Grubdac parts from Mouser and the mini-B is back ordered until December! Will the min-AB work, the pinouts look the same and everything I can find says that the AB will accept the B but I wanted to ask first. Thanks
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post #81 of 952
10/1/09 at 10:31pm
I was going over the BOM for GrubDAC and I noticed that C9 is 1000 uf!! The USB spec for the TOTAL capacitance on Vbus for an upstream port ( on the device, not the host) is between 1 and 10 uf. You might want to try a smaller cap This might be your surge problem.
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post #82 of 952
10/1/09 at 10:32pm
Thread Starter 
Quote:
Originally Posted by Billyk View Post
Wouldn't ya know! I went to order my Grubdac parts from Mouser and the mini-B is back ordered until December! Will the min-AB work, the pinouts look the same and everything I can find says that the AB will accept the B but I wanted to ask first. Thanks
Molex part is 56579-0519 compatible. You can see here as reference. I used the same part as the gamma1.

And if you see here, it should be on the Mouser online bom link (both are on the BOM so you need to remove the backordered one).
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post #83 of 952
10/1/09 at 10:33pm
Thread Starter 
Quote:
Originally Posted by stwspoon View Post
I was going over the BOM for GrubDAC and I noticed that C9 is 1000 uf!! The USB spec for the TOTAL capacitance on Vbus for an upstream port ( on the device, not the host) is between 1 and 10 uf. You might want to try a smaller cap This might be your surge problem.
The is the same size part as the BantamDAC C7 which has been around for quite a while. The Grub has powered up on my laptop with no issues.
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post #84 of 952
10/2/09 at 7:34am
Quote:
Originally Posted by cobaltmute View Post
Molex part is 56579-0519 compatible. You can see here as reference. I used the same part as the gamma1.

And if you see here, it should be on the Mouser online bom link (both are on the BOM so you need to remove the backordered one).
Thanks, that'a the one I used. I did not use the online BOM I did use the excel sheet though, thanks for that.
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post #85 of 952
10/2/09 at 8:47am
Thread Starter 
I've added a note to the Excel post about the part so people see it.
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post #86 of 952
10/3/09 at 1:32am
oh yea got it up and running with the carrie! sounds really great! Coming from the bantam its got a more expansive sound and much more lively.
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post #87 of 952
10/3/09 at 7:45am
Thread Starter 
Glad to hear that you got it running.

Any notes from the build?
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post #88 of 952
10/3/09 at 6:15pm
The build went pretty smooth. I tried kwame 100ohm resistors for R7/6, after listening to the default and couldn't hear much of a difference. Led should be placed near the usb, also it would be nice to have the G,OR,OL in a line sequence instead of 2x2 block. I connect 5v on the carrie to the V+ and 0v on the carrie to GND, which I think is correct.

Overall, im impressed with the dac. I have two mini3 amps with alien dac (blackgates bypass with vitaminq) and bantam dac (visnay/cerafines) and imo the grub sounds much better with the mini3/carrie.
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post #89 of 952
10/3/09 at 6:33pm
I got my boards the other day, and now I'm not sure what to do in regards to ordering parts. I'll have to wait on it a while. Good to hear it's getting a good reception. I can't wait to build mine.
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post #90 of 952
10/3/09 at 6:52pm
try getting 2707 on ebay, I got two for $7.
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