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henri47 wrote:yes.
In my opinion the only problem could be a fault in the dacboard or a corrupted I2S data signal. It also puzzles me the signals are so deformed when I made connection with the digital In connector on Dac board You will hear something (even noise) even if corrupted I2S. The only way to get silence is for the polarity of the all the internal DACs to cancel each other.
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If you don't get a lock you won't get noise.
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@git @Brian I searched for I2S on the web and found how the 3 signals should be. Comparing them with the I2S signals in my dac I see they are perfectly normal. So no corrupted signals. As you stated in your post I hear nothing: no hiss, no crackling: perfect silence. I changed dip switch S/PDIF autoselect (SW2,5) to Bypass. The Dac muted and refused even to play S/PDF signals Edited by user Tuesday, April 3, 2012 10:40:02 AM(UTC)
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Is the I2S locking? Are you sure there is music coming from the source?
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I have reinstalled the dac-board and took some oscillo pics. You can see the signals on the DAC Din connector are very different from those found on the I2S input header of the sidecar. Dac-board not connected: signals are normal on I2S input header of the sidecar and appear so at ribbon connector of Din on DAC-board Dac-board Connected: signals are normal on I2S input header of the sidecar and are heavily distorted or not present at ribbon connector of Din on DAC-board. On the I2S input header of the sidecar I can observe when music is present or not. The data signal is present with music being streamed and is absent when music has been stopped. On Din of Dac-board NO Data signal is present. When stopping music, nothing changes. So something must happen when loading the signals. @Brian: No lock on I2S Edited by user Tuesday, April 3, 2012 11:22:43 AM(UTC)
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Double check the solder joints on the sidecar and the DAC, and make certain there are no PCm or DSD jumpers in place.
Also check that there are no shorts from pin to pin at the DAT DIN header, or from any pin to GND.
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Hi Rus, I double checked all solder joints on sidecar and DAC. Could not find something to worry about, though used no isopropyl to clean the boards. Did a reflow of all solder joints on side car and Din connector on DAC. PCM jumpers are not soldered in place. What I do not understand is why S/PDIF signals, routed via the same relays, joints and connectors are delivering their signals on the same pins at Din connector of DAC without major problems. Edited by user Tuesday, April 3, 2012 11:53:51 PM(UTC)
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try to do like me use 1 or 3 on input selector board to feed 1.85 vdc to sidecar position "b" to trigger transistor to let through 5vdc fromBIII to engage relays
set sw block 2 pos5 to OFF
best
Leif
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Hi Leif, I'll try this today. Although I doubt it will help. Yesterday I've set SW2,5 to bypass and even S/PDIF did'nt work anymore. My opinion is the DAC, receiving an enormous quantity of HF-rubbish coming from other components and different inputs , is in a continuous state of hesitation about the signal to be handled. When I look at my build I feel uneasy about the lack of shielding around the components. It is not an example of good HF building practice. A few decennia ago I have builded an Amateur radio receiver for 10,20 and 40 meter band. It would not have worked without torough shielding and decoupling of the different circuits. This is digital stuff, so very fast switching and generating a lot of HF. I hope we can solve our problems, but if I would not succeed I'll try to do a rebuild with completely shielded units. Hope to see you have success and I keep following your posts, Henri Edited by user Wednesday, April 4, 2012 1:09:06 AM(UTC)
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Herni, the setup you are building is quite common, you should not be seeing what you are seeing. If you have a good solid switch at the relays the input side and the output side would be identical, as they are exactly the same net. So there has to be a disconnect somewhere.
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One thing to check would be the Placid shunt current with I2S selected (relays energized) make sure it still has headroom when things should be playing.
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Also the purpose of switch 2,5 is to turn off (bypass) SPDIF autodection. So it is natural SPDIF would not work after that, but what it does is prevent the DAC from thinking that an I2S signal is a SPDIF signal. Normally this is not required, but it can be helpful in troubleshooting.
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Hi Russ, Thanks for the trouble you took in thinking along with me. I'm happy to tell you my problem wit I2S is partially solved. Today I wrote in a PM to Gunnar: Quote:Problem solved. A least one of my problems. Problem with the sidecar was TPA deliverd the kit with a BC550C transistor. I assembled the kit and it did'nt work. After studying the schematics I saw the pin layout of the BC550C was not suited for the print layout. I replaced it by a transistor I had lying on the shelf with a suitable pin layout (BCE). But is was a different transistor with different characteristics. I adjusted the base transistor on the sidecar to 600 Ohm. After mounting the sidecar in the circuit I checked if the relays are activated via the B terminal. They did; I could hear them softly clicking. Checking I2S signals with my scope indicated the signals did not arrive at the dac terminals. I searched and placed a question on the forum related to BIII. After days I could pin down the problem to the relays. It seemed the base current via 600 Ohm resistor was big enough to activate the transistor partially but not fully switch it on. One or two relays are clicking but not all tree. So not all tree I2S lines where connected to the DAC terminals, hence no sound.
I replaced the 600 Ohm resistor by one of 100 Ohm I had on hand. And the first problem was fixed. For the first time I could hear music imported via USB/I2S.
BUT: this music, like the music coming from the S/PDIF sources loses lock constantly and randomly.
New problems, with hopefully new solutions. Kind regards Henri
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Ahh yes, the transistor there should be BC639.
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The kit ships with a BC639. Not sure how you ended up with the wrong transistor.
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