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This has been an intermittent problem that has turned to a constant problem. The system worked great for about a year or so...
Setup:
Twisted Pear (TP) S/PDIF Transceiver -> OPUS -> Ballsie (all vintage from 4-5 years ago)
Symptoms
Power on: 3 reds/1 green on transceiver, since no digital signal incoming, that seems sensible.
I can connect a variety of digital sources and here's what happens.
CD player (I've tried a couple, that all work with a different DAC) SPDIF out to TP Transceiver All green lights (solidly on) on the board, no analog out of OPUS
Squeezebox touch digital out to transciever -> All green (solidly on), no analog out of OPUS
Squeezebox touch digital out to Cambridge Audio DACmagic (it has a digital OUT as well) DACMagic digital out to TP transceiver -> lights flicker red/green but SOME, albeit crackly, audio out.
This is actually a stripped down version of my system. I removed the TP USB receiver and OTTO so as to remove those possible confounding issues.
I have tried different cables, different sources etc. Any ideas folks?
Thanks,
Ryan
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Can you post pictures of your whole setup and your current switch settings on the transceiver and DAC?
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I will do it. It may be a bit as I have some dis assembly to get a good look at it. Thanks Brian for the quick reply. Cheers, Ryan Edited by user Monday, January 7, 2013 12:24:52 AM(UTC)
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Photos of OPUS and Transceiver settings: ... I'll send more of the entire set up in another posting. I wasn't sure how to post photos directly so I have inserted links to a flickr site. Let me know if you cannot access them. Cheers Ryan Tranceiver SettingsDAC Setting
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Opus with Ballsie below and Transceiver moved out of the way: View 1With Transceiver back in position (sort of...): View 2The long leads are due to the fact that I removed USB Rx and OTTO. Cheers, Ryan
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Anyone had a chance to look at things?
Cheers,
Ryan
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Can you disconnect the Ballsie and see if there is audio at the outputs of the DAC itself? If not, then check (carefully) the voltages at the output os the two regulators. They should be 3.3V for VD and 5V for VA. You can measure across C13 and C14. Edited by user Thursday, January 24, 2013 9:14:18 PM(UTC)
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No problem to remove balsie and get at the balanced outputs of the opus. However, I don't have anything that takes a balanced input. Will I dork anything up if, for testing purposes, I use half of the balanced signal, i.e. just gnd and +? out of the DAC and feed a pre-amp?
Thanks,
Ryan
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You can measure for AC voltage on the outputs using a DDM. No real need to connect it to a pre-amp. If you want to connect it than use + out and gnd. |
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With coupling cap to be safe.
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So yes, there is a problem here: Voltage across both C13 and C14 is 7.6VDC. That is what the input voltage reads coming from by TP power supply feeding the DAC... So are the voltage regulators toast? Is it salvageable or do I start over? Odd thing is it ran just peachy for a couple of years. Thanks for the help All! Ryan Originally Posted by: Brian Donegan  Can you disconnect the Ballsie and see if there is audio at the outputs of the DAC itself?
If not, then check (carefully) the voltages at the output os the two regulators. They should be 3.3V for VD and 5V for VA. You can measure across C13 and C14.
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Ooops, my bad. Try measuring across C17 and C18, instead.
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Oddly... BOTH have 4.96V across them. Hmmmm ????
Ryan
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Those voltages are fine for the WM8740.
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Originally Posted by: Russ White Those voltages are fine for the WM8740. Yes, I keep forgetting how old the module is.
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Hah me too, I had to look it up. :)
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Shall I try getting sound out of OPUS as suggested above? Couple cap -> pre amp?
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Yes, that would be a good next step.
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I usually test with an old set of ear buds I have. I put an alligator clip on the base of the plug (GND) connected to GND of the DAC, then touch the tip to the output terminals to test for output. It's not good for the headphones (DC offset), but they are junky, and you definitely don't want them in your ear during the test.
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If you go from -OUT to +OUT instead of to GND there will be no DC. I have tested this way several times. :)
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