Gamma-2 (γ2) DAC Thread
Jul 26, 2009 at 2:29 AM Post #211 of 2,154
I don't think there are fm's there. nichicon's though.

the grey box caps are vishay from mouser (1uf). not red, but they were onhand
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re: lighting, I do spend a little time getting it right, but one thing that cures a lot of evils is the 'shadow highlight' tool. it compresses down (either direction) and fixes a LOT of lighting problems.

also, never use flash. use available light and live-view to point lights off walls. this means a tripod is a must-have and a self-time to trigger itself is also needed.
 
Jul 26, 2009 at 3:57 AM Post #213 of 2,154
Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif
gotta admit, I used the old flood-n-suck method on those 2 so28 chips. but it gets the job done with little hair-pulling
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Got to try that method next time I solder one of those chips, always thought that there was a danger of removing to much solder from the joint but your photos show otherwise. Nice work!
 
Jul 26, 2009 at 4:18 AM Post #214 of 2,154
Congrats, linuxworks. That's very clean solderwork. You're the second person to ever hear a γ2, even before I soldered the first joint on mine!
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Jul 26, 2009 at 5:58 AM Post #219 of 2,154
Quote:

Originally Posted by amb /img/forum/go_quote.gif
Congrats, linuxworks. That's very clean solderwork. You're the second person to ever hear a γ2, even before I soldered the first joint on mine!
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I'm no stranger to that phenom. when I was developing the 'volumaster' code for the digital attenuator, another guy I was working with (rwhite) was the first to hear and see it work, even before me. I was writing code, sending to him, getting feedback and debugging until he said 'I hear sound!'. it wasn't until days later that I heard my own unit working
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Jul 26, 2009 at 6:39 AM Post #222 of 2,154
Quote:

Originally Posted by MisterX /img/forum/go_quote.gif
And the white noise when an unused S/PDIF input is selected is minimual...


confirmed, and then some. this seems to be a well behaved dac. I'm not sure there's any urgent (if any) need for external muting.
the dac I had just before this one (an ebay china special) had a relay for muting. an actual loud mech relay for when error==true and all that stuff.

sounds good, in theory, except when I run my media player (popcorn hour) and when you change programs or chapters or even go in/out of pause, you can trigger a mute and the relay starts clicking on you. it gets annoying!

this dac has no relay and while it has no external muting, it has no harsh problems while doing some video playback tests and while switch to/from audio (audio = 44.1, video = 48k). I downsample all my 5.1 stuff to 2.0 so that I can watch movies with a 'quality dac' and that means a stereo dac (lol).

so far, music and movies are fine with this dac. its now in place where the previous one used to be. I have a PGA vol control chip following the output of the dac and that works fine, also.

I had my y1 board build from a long time ago, and I didn't want to deal with making another just to have usb locally. I can convert usb to spdif and from then, spdif is just one of many spdif inputs that can be selected from. keeping it as that half top layer also lets me get access to the line-out jacks and put molex connectors there.

I was not planning on leaving them sandwiched like that, but I think I will, now. it saved me having to make a cable (lol).
 
Jul 26, 2009 at 7:12 AM Post #223 of 2,154
Actually my conclusion is a little hasty, I should have built at least one of the three Gamma 2 boards without the SRC4194 (or AD1896AYRS) to see how much of the white noise is being dealt with by the ASRC.
It looks like it would be pretty easy to add the ASRC and associated parts after the fact if one of the participants of the prototype group (with access to a scope) wants to try it.
You might save me from ripping all of that stuff back off one of the boards to test it.
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Jul 26, 2009 at 11:11 AM Post #224 of 2,154
Quote:

Originally Posted by MisterX /img/forum/go_quote.gif
Actually my conclusion is a little hasty, I should have built at least one of the three Gamma 2 boards without the SRC4194 (or AD1896AYRS) to see how much of the white noise is being dealt with by the ASRC.
It looks like it would be pretty easy to add the ASRC and associated parts after the fact if one of the participants of the prototype group (with access to a scope) wants to try it.
You might save me from ripping all of that stuff back off one of the boards to test it.
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I am doing just that on mine. I am leaving off the ASRC chip (along with everything else in the "optional" box as shown in the schematic) and test in that configuration, and then I will add those parts later.
 

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