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If you decide to load the analog outputs for testing use something pretty low. Say 100-470R directly from both ends(+ and -) to GND. The put your scope gnds right at the analog GND.
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Photo shows scope connections to both channels. Loading with 500 ohms. Scoped earth connection made here. Note the shortened ribbon cable. Edited by user Wednesday, December 14, 2011 4:04:39 AM(UTC)
| Reason: Not specified S.Ward attached the following image(s):  Scope Connections.jpg (94kb) downloaded 249 time(s).You cannot view/download attachments. Try to login or register.
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Photo shows waveform of both channels but they appear overlapped almost as one, note this is at power up and the mute is still active. Note both outputs are offset by around 1.25V - is this normal ? Edited by user Wednesday, December 14, 2011 4:05:47 AM(UTC)
| Reason: Not specified S.Ward attached the following image(s): Power On ( muted).jpg (124kb) downloaded 247 time(s).You cannot view/download attachments. Try to login or register.
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Photo shows what happens when the mute drops off after 1-2 seconds. This difference could be why I see the large offset on the IVY - if it were connected. Note the average difference between the signals is around 1.25V .. Edited by user Wednesday, December 14, 2011 4:19:39 AM(UTC)
| Reason: Not specified S.Ward attached the following image(s): After Mute released.jpg (135kb) downloaded 242 time(s).You cannot view/download attachments. Try to login or register.
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Photo shows what happens after a power off - on 2sec restart. I can subtract the two signals to compose a good looking output signal. But trying to keep things simple.. Notice the offset has disappeared. Edited by user Wednesday, December 14, 2011 4:20:59 AM(UTC)
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Could this be something to do with the mute ?
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Disconnect the SPDIF ribbon on the DAC side. What happenes?
Also do you have all of the SPDIF inputs on thee SPDIF4 terminated?
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Also try testing with the firmware chip removed.
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Also I would put all of the DIP switches in the opeen ("off") position for the test.
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S.Ward wrote:Photo shows what happens when the mute drops off after 1-2 seconds. This difference could be why I see the large offset on the IVY - if it were connected.
Note the average difference between the signals is around 1.25V .. It almost look in that shot that one end is loaded and one end is not. Perhaps a loose test rig?
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I cant test with the SPDIF disconnected - catch22 without a signal to convert the mute will not release... I did try regardless but I just get the initial output as before. I have originally had the three remaining inputs open but have shorted them out - since last week. No effect noted. No the rig is fine I have 499 ohms measuring across each pin with a meter. its not just coincidence that this would fit with the large dc offset I will see at the IVY outputs if I connect it. Edited by user Wednesday, December 14, 2011 7:31:08 AM(UTC)
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Its a process. I don't have the thing in my hands so I have to ask you questions. :)
I didn't mean shorted on the inputs (but that's ok too).
Please remove the firmware as I asked and try again.
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Tried removing firmware chip with all switches off. No change same result.
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Hmmm... This is very odd indeed. Nothing I can reproduce for sure. Let me ponder this a bit. I may email you with some ideas.
It could simply be that the DAC is somehow damaged (by any number of means). Though I have never seen one fail quite like this before for certain.
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A couple of points to note here, one that I deliberately kept the DAC in its bag until I assembled it & I used Anti-static tie, matts, soldering station and workholder. I used a stereo microscope to check best I could for any solder tracks post assembly / before testing. So all precautions taken because there was no indication to say the boards should be assembled under anti-static conditions. Always best to hope for the best, but assume the worst.
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Oh ESD is not the only possibility here. But it is good you used common sense.
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If I experience with BIII turn on\off thumb, some HF oscillation when reproducing high pitch music details from the DAC itself, could it be the same problem?
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AndriyOL wrote:If I experience with BIII turn on\off thumb, some HF oscillation when reproducing high pitch music details from the DAC itself, could it be the same problem? Hi Andriy. It's impossible to know based on that little bit of information, but if I remember correctly you are not using the differential outputs as intended, nor are you using our output stage. If you are only using a single end of the output you would get exactly what you are seeing. The OPs situation seems to point to a damaged DAC or possible a bad solder joint (maybe at the chip). We are looking into it. Edited by user Friday, December 16, 2011 10:43:52 AM(UTC)
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Likewise any other quantizer setting, except 6 bits, won't work either, according to quantizer setting graphs on p27 of Integration guide? I have only continuous beep sound coming from the dac without any other out-coming signal when quantizer settings are changed regardless which setting to choose, 7 or 8 bits. Differential mode is set to true, also tried to pseudo. Inputs and outputs are not paralleled, OSF is USE, DPLL - default, multiplier 1X. Edited by user Wednesday, December 28, 2011 1:17:51 PM(UTC)
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You must know how to parallel the inputs outputs for some modes to work correctly.
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