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Gamma-2 (γ2) DAC Thread - Page 141

post #2101 of 2154
BTW, you might get better response to these questions by posting on AMB's forum.
post #2102 of 2154
I would just like to say that I am watching/subsrcibed to this thread and only havent said anythign because I have no idea what to say in this situation. I'm not quite at that level yet heheh.
post #2103 of 2154

@jdkJake... I don't think reflowing will solve the issue. Nor will posting pics. This was a working Y2 for the past year or so. Just to reiterate - I shorted out a metal knob and metal 1/8" connector, which in turn was connected to and subsequently zapped my Gamma 2 with probably way more voltage than what U7 or U5 can handle. This is just a guess. The one anomaly is more voltage being fed to C26, which should be getting around 2.2v.


I'm going to post to ambs forum, but usually come here first. This is my DIY home. ;)

post #2104 of 2154

Might be a good idea to check the voltage on U5's VMIDR and VMIDL pins but replacing U7 sounds like a pretty reasonable place to start to me.


post #2105 of 2154

I'm assuming it's easiest to check this by using the vias on the the bottom of the board for those respective positions. What voltage reading should be normal? ~2.2v?

post #2106 of 2154

Closer to 2.3 then 2.2 volts but both sides being roughly the same is more important then the actual reading.

post #2107 of 2154

So to complete the proverbial circuit here's an update with my fried Gamma 2:


Measured VMIDL and VMIDR and got close the 2.3v readings. Then measured Pins 1/3 and 5/7 and got the 3.5v readings on 1 and 3. 5 and 7 measured just fine. I still got 4.5v readings at C26.


I proceeded to order a new U7 and U5 (just in case) and pulled out some of the box caps around U7. Then using some chip quik I pulled U7 and put the new one in. Then I put back the box caps I pulled. Fired the puppy up and took some measurements via USB from both a Mac Pro and MacBook Pro...


Mac Pro

VMIDL 2.326
VMIDR 2.315

pin1 2.327
pin3 2.312
pin5 2.298
pin7 2.273

MacBook Pro

VMIDL 2.264
VMIDR 2.254

pin1 2.270
pin3 2.253
pin5 2.241
pin7 2.216


Finally, I plugged in my CTH and some phones and Voila! Everything works again!


I've got an extra U5 (WM8471) now if anyone needs it.



post #2108 of 2154
Good news mullet.

What did you think of using chip-quik? I had to temporarily remove the crystal oscillator from mine (long story) and used a precision tip heat gun with the part surrounded by a cooper tape cone. It worked well, but that was only four pins. Not sure how it would work for the multi pin chips.

I see where Fry's carries chip-quik, so, I might pick some up to have on hand.
post #2109 of 2154
Chip Quik really works for SMDs, but helps with through hole devices as well. It's definitely worth having on hand. I'd imagine it would be helpful with the receptacles and pin headers if they needed to be pulled. Otherwise, I'd think they'd be near impossible to pull.
post #2110 of 2154

The Android-powered smartphone Samsung Galaxy S III interworks with the Gamma 2:


post #2111 of 2154

sorry about the stupidest question in the world, but


is the gamma 2 still the best in it's price range


what about for $100 more - is there something better?

post #2112 of 2154

I'd say it's still pretty damn good. Another alternative that gives way less features in terms of I/O, but is still really good none-the-less is the PupDAC. I'm also going to be building the Subbu v3 DAC, which is based off the ESS Sabre 9023.

post #2113 of 2154

I think I want to add balanced output to my Gamma2, few questions:


1) I should just tap the Balanced outputs of the chip, add some caps, and then it should be good?

2) The normal outputs would function fine if I didn't use the XLR's, correct?

post #2114 of 2154

1)  Capacitors and resistors. And you will also need to figure out where and how to add the XLRs.

2) Yes.

post #2115 of 2154
Originally Posted by MisterX View Post

1)  Capacitors and resistors. And you will also need to figure out where and how to add the XLRs.

2) Yes.


I am adding them through holes in the case where i'll string the wires through. So I can just tap VOUTLP/N and VOUTRP/N, add a capacitor or 2, and then ill be good to go? Got any recomendations as to what series of caps and resitors I should use?

Edited by DutchGFX - 5/3/13 at 10:36am
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