Gamma-2 (γ2) DAC Thread

[amb]

Quote:

Originally Posted by francisdemarte /img/forum/go_quote.gif Can I wire L+/L- and R+/R- test points into a TP IVY III + PS and get balanced outputs?

In theory, yes. I have not tested that though.

 

[slowpogo]

I finished my build last night (y1 + y2, Full++)...it all seemed to go well. The SMD chips went pretty well. But alas, no music.

Is there a reliable way to test for solder bridges on the SMD chips? I've used the multimeter to test continuity of adjacent legs - but obviously, some of them might actually be connected internally.

For example, on the SRC4192IDB, if I measure continuity of adjacent legs, the first several all show continuity (1&2, 2&3, 3&4 etc). But I've reflowed, flooded and solder wicked, done all the tricks several times now. I cannot see any bridges even under a magnifying glass. I've checked for continuity this same way on all the other SMD chips, and none of them show continuity between adjacent legs - only those first several of the async sample converter.

I've both boards under the magnifying glass, reflowed many joints, but still nothing...

 

[amb]

slowpogo, use the schematic diagram to help you determine whether any adjacent pins should be connected to each other.

 

[ShinyFalcon]

Quote:

Originally Posted by slowpogo /img/forum/go_quote.gif I finished my build last night (y1 + y2, Full++)...it all seemed to go well. The SMD chips went pretty well. But alas, no music.

First off, what works and what doesn't? Is your computer able to find the USB device? Does the light light up green? Have you tried using coaxial/optical? How are your voltage test points? Does your y1 work by itself? Does the contact pins/receptacles show continuity? Did you install the pin on JP1D?

 

[slowpogo]

Quote:

Originally Posted by ShinyFalcon /img/forum/go_quote.gif First off, what works and what doesn't? Is your computer able to find the USB device? Does the light light up green? Have you tried using coaxial/optical? How are your voltage test points? Does your y1 work by itself? Does the contact pins/receptacles show continuity? Did you install the pin on JP1D?

Alright ShinyFalcon...I sense frustration that you feel I was asking for help without providing any info. I was really just going after the solder bridge stuff and was aware I left out a lot, but I wasn't quite ready for full-blown debugging crisis mode. Since you asked, however, we might as well go there:

1. Computer finds USB device OK
2. My switch lights up red
3. I've tried both USB and coaxial
4. Voltage test points read fine
5. I installed the pin.

All jumper settings are as they should be (basically, all open except JP1U shorted with resistor lead). I have cleaned the board with alcohol (including around the SMD pins with a toothbrush/alcohol).

As far as the y1 working on its own -- this means I have to temporarily install the 5 connecting wires, correct, to test if it works on its own?

 

[amb]

Quote:

Originally Posted by slowpogo /img/forum/go_quote.gif 1. Computer finds USB device OK

OK, this means at least U1U and U2U are ok.

Quote:

2. My switch lights up red 3. I've tried both USB and coaxial

Try reflowing the joints of the CS8416.

Quote:

As far as the y1 working on its own -- this means I have to temporarily install the 5 connecting wires, correct, to test if it works on its own?

You can use the y2 board as the "bridge", no need to connect actual wires.

 

[MisterX]

Or you can just install the jumper across J2U pins 1 and 2, connect either or both of the S/PDIF outputs on the USB board to the DAC board, plug in an external power supply and away you go.

 

[ShinyFalcon]

Quote:

Originally Posted by slowpogo /img/forum/go_quote.gif Alright ShinyFalcon...I sense frustration that you feel I was asking for help without providing any info.

Oh no, it wasn't that.

Sorry if it seemed like that. I was rushing a bit and after reading it, my message does have a negative tone to it. Just think of it as a canned response.

 

[thoppa]

Quote:

Originally Posted by amb /img/forum/go_quote.gif Changed from what?

Hi, sorry, lazy post....

The CS8416 has a PLL filter on pins filt and agnd ( 7 and 8 ). There's a diagram on page 21 of the datasheet. It says at the bottom **** For best jitter performance connect the filter ground directly to the AGND pin. See Table6 on page 54 for PLL filter values.
For 32-192Khz
RFLT CFLT CRIP Settling Time
23kΩ 22nF 1nF 4 ms

On the y1 the components are C18D, C19D and R4;
3kΩ 33nF 1nF

This would appear to double ( ? certainly quite a change....) the settling time, so it seems to agree with the idea of using sample rates from 32-96Khz instead of 32-192Khz ? I don't know how this chip or PLL filters work so I'm just guessing.

So I'm curious about the filter change from the one given in the datasheet....and what would be the effect on jitter of changing rflt and cflt.

 

[slowpogo]

Quote:

Originally Posted by amb /img/forum/go_quote.gif Try reflowing the joints of the CS8416. You can use the y2 board as the "bridge", no need to connect actual wires.

I reflowed those; they all look shiny and proper, but no change. I tried the y1 output using the y2 as the bridge, but same outcome.

I'm not sure if this is significant - I plugged in the y1 DAC board to my 5V power supply, nothing else connected to anything...when I check the 3.3v test pad against ground, I get 1.9v.

But 4.5 to ground measures as it should (in my case 4.75v).

On a side note - it's frustrating because I'm not entirely sure I've got my Emu 1212m configured correctly to use its coax out; I've never used its digital outputs before and the Patchmix software is notoriously confusing, so that's another unknown I ironically can't be sure about until the y1/2 are working. Also, I'm using Foobar to test USB input; but that has its own quirks and I'm not entirely sure I'm doing that right either. When the y1 is plugged in, I have the option to choose DirectSound: USB Audio Device, and I choose that. I play a tune, and the visualizer jumps around like it's all hunky-dory...but no sound.

 

[thoppa]

Hi,

I've had similar problems. I reflowed CS8416 several times to get the y1 working. If you're getting anything other than 3.3V then the reg isn't working - it might need reflowing or replacing. Check the voltages on pins 1 and 5 - in and out - and pin 3 - start - which is shorted to pin 1. Check the circuit diagram to make sure I've got this right

If you get a green light on y1 it means either the cs8416 has a bridged connector or you are getting a correct signal from the EMU. If you can get a red light also from another source selection, and green from the emu, then it means the emu signal is being received and the cs8416 has successfully locked.

 

[slowpogo]

Quote:

Originally Posted by thoppa /img/forum/go_quote.gif Hi, I've had similar problems. I reflowed CS8416 several times to get the y1 working. If you're getting anything other than 3.3V then the reg isn't working - it might need reflowing or replacing. Check the voltages on pins 1 and 5 - in and out - and pin 3 - start - which is shorted to pin 1. Check the circuit diagram to make sure I've got this right

That was all it needed - I reflowed the regulator, and all is good, MUSIC!!!

EDIT: OK, it was working like a dream for about 20 minutes. But now I'm getting intermittent bursts of static followed by a high whine. I'm guessing this is some kind of connectivity issue between the y1/y2 boards? I've tried kind of pressing on the boards, or rocking them, in case they are not quite connecting somehow, but it doesn't help.

Hope to get this resolved quickly - it was sounding fantastic

 

[jarpatus]

Quote:

Originally Posted by slowpogo /img/forum/go_quote.gif That was all it needed - I reflowed the regulator, and all is good, MUSIC!!! EDIT: OK, it was working like a dream for about 20 minutes. But now I'm getting intermittent bursts of static followed by a high whine. I'm guessing this is some kind of connectivity issue between the y1/y2 boards? I've tried kind of pressing on the boards, or rocking them, in case they are not quite connecting somehow, but it doesn't help. Hope to get this resolved quickly - it was sounding fantastic

I had similar problems, first it worked like a charm but then most weirdes pitching whine, cracks pops etc. and finally led went red first for seconds then for minutes etc. Turned out it was flux. I had cleaned the boards using isopropyl alcohol but it was not enough, somehow there were still enough left to short circuit stuff.

So try to clean you boards again very carefully? I actually submerged whole boards to pure ethanol to get everything off but that's not probably recommended as connectors and switches probably will suffer no matter how well you dry them. Next time I do throughout cleaning BEFORE soldering connectors and switches

 

[thoppa]

I've had crackle then silence from the y1/y2 join - it was the iis connections. I desoldered them and reworked the connections and all was fine.

I don't use flux.

 

[slowpogo]

I did a thorough cleaning of the boards, with an alcohol/acetone mixture...fingers crossed, but the static/whine is gone, and has been playing beautifully for a while now.

EDIT: OK, now it's back again. thoppa, what are the "iis" connections?