Gamma-2 (γ2) DAC Thread
Nov 21, 2009 at 4:00 PM Post #1,009 of 2,154

Conte Zero

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Reflowed them, quick multimeter checked for shortcircuits and false joints... connecting... and voila green light...
Never mentioned you have just a won a free week in Italy if you come nearby?
wink.gif


The problem seemed to be a defective U2D joint... I don't know how I kept missing it before... well, again thanks, I'll test the DAC for a while and I'll be sure to post photos later.

Ric

EDIT: Actually the red switch problem manifested again while inserted into to case, I tried moving the pcb a little and so on, looking again at the mating connector, then I realized that the mating connector soldered tips were left uncutted as they were very short, but they, once inserted in the case, were sometimes touching the aluminum... cut them and as predicted all is again working perfectly (actually, due to the faulty joint a lot better than before).

Thanks again Ti and ShinyFalcon, offer for the trip to Italy is still valid!
wink.gif
 
Nov 24, 2009 at 6:43 PM Post #1,013 of 2,154

Wizik

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Hi all, please, I need to know, if I can change U4D on y1 (Microchip Technology MCP100-315DI/TO or Maxim/Dallas DS1818 reset manager TO-92) for something else, because I can´t found it, maybe I lost it. Please help, I can´t buy it anywhere in my country.
 
Nov 24, 2009 at 10:12 PM Post #1,014 of 2,154

amb

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Quote:

Originally Posted by Wizik /img/forum/go_quote.gif
Hi all, please, I need to know, if I can change U4D on y1 (Microchip Technology MCP100-315DI/TO or Maxim/Dallas DS1818 reset manager TO-92) for something else, because I can´t found it, maybe I lost it. Please help, I can´t buy it anywhere in my country.


Sorry, those are the only pin-compatible devices I know of . Farnell is your closest source, the part number is listed on the γ1 website parts list.
 
Nov 25, 2009 at 3:37 AM Post #1,015 of 2,154

PScal

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Hey look, a picture!

4132678900_6c767a6d2a_b.jpg


Waiting for my forgotten u2 before I go any further... Any obvious errors so far? This is my first ever surface mount build (and 2nd build ever). Those voltage regulators are so tiny. One of them could be mistaken for a flea. I made sure all of the grounds were continuous and there were no bridges, but maybe I got something backwards...
 
Nov 28, 2009 at 1:41 AM Post #1,016 of 2,154

pidesd

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Quote:

Originally Posted by Conte Zero /img/forum/go_quote.gif

Thanks again Ti and ShinyFalcon, offer for the trip to Italy is still valid!
wink.gif



i d be careful guys, i heard italians had lots of venereal diseases.
wink.gif
 
Nov 30, 2009 at 7:36 AM Post #1,018 of 2,154

mattcalf

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Pictures do not do it justice how tiny these things actually are, my AMB order arrived today in an package. I opened it up expecting bags of stuff to fill the envelope, however, I had to pull our a DVD brace which contained the parts.

The PCB's are things of beauty, I can't begin to imagine how long it would've taken to plan the design and layout.

Can't wait for my Dealextreme order (flux, tweezers, lead clippers) to come in so I can start building this DAC. :

Thanks Ti.
smily_headphones1.gif
 
Nov 30, 2009 at 4:31 PM Post #1,019 of 2,154

ujamerstand

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grr, they ran out of 1.5K resistors at mouser, and there is no other equivalent in terms of size... RN55's are too big. Digikey has them but thats another 20 dollars of shipping, I can get it along with the enclosure at Newark, but there's a 20 dollars handling fee PLUS shipping as well. Would it be okay if I go one value up or down? Or tombstone a larger RN55 in the R16D, R2U and R5U positions? If there's any other way I can go to save that cash, I would. But I don't really want to derail from the schematics if I can help it. I've already decided to use 270-221-RC at R11D and R8U positions since those are out too. Any input would be helpful!

Edit: Well, it seems after a bit of research I might as well order directly from fernell for the enclosure and missing resistors. Thanks for viewing!
 
Nov 30, 2009 at 8:58 PM Post #1,020 of 2,154

amb

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ujamerstand, 1.5K is the value shown in the PCM2707 datasheet for R2U and R5U, I think you can get away with using the next step up or down, but I would replace them with the proper 1.5K resistors when you can get some. For R16D, you can go down a step in value which will raise the TPS2115A's current limit protection threshold a bit.
 

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