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Hi,
I just finished making the OPUS DAC kit (power supply, dac module, USB input).
At first, the dac sounded wonderful. After running it for about ten minutes, the sound went away, only left the static noise.
Now, when I connect the USB cable, the windows and mac machine both recognize the sound card as USB dac. However, I only hear noise when the USB cable is connected. I hear the noise to be high pitched, low volume static noise (no music). Whenever the cable is disconnected, I don't hear any noises. What shall I do to troubleshoot the problem further?
Please let me know how I can describe the problem further.
Thank you,
Peter
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What bit rate are you trying to play from the computer. The USB module only supports up to 16-bit/48kHz.
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Hi,
Thank you for the quick reply. I ripped the CDs using FLAC. They're CD quality songs - 16 bit 48 kHz. None of them is higher than the CD quality songs.
Cheers,
Peter
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What to you get from the line outputs of the USB module?
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Hi Brian,
Would you tell me if I understood you correctly? Basically, I should try listening using the dac output of the USB module, right?
Thank you,
Peter
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Yes. The USB Dac has I2S/SPDIF outputs as well as analog line outputs. I am trying to identify if the problem exists in the USB module or the Opus module. Also, are you using a Metronome?
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Hi,
I do not have the metronome - possibly my next project.
Just to confirm the connection, this is correct, right?
OPUS - USB receiver
BCK - BCK
MCK - SCK
LRCK - LRCK
DIN - DO
G - GND
I will update you later tonight using the USB dac output.
Cheers,
Peter
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That looks right. Did you change any settings on the Opus after it was working and before it stopped? Also, what power supply voltages are you using?
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Hi Brian,
I followed the settings for the stereo configuration from the manual 2.0, and I have not changed them at all. The music went away in the middle of playing.
I tuned both power sources to be 7.5V dc as recommended. Just curious, why is 7.5v recommended over other values? Wouldn't it be better to use 5V instead, if it will be used as 5V? I read forum posts trying to find the answer, but I never really understood why.
Cheers,
Peter
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Hi Brian, I just connected the SE output of the USB dac to a stereo system, and I don't hear any sound. I tried it on both Windows and Mac, and they do recognize the dac. The stereo system input sockets work with other devices. Thank you, Peter Edited by user Tuesday, July 14, 2009 6:00:48 PM(UTC)
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Hi,
The SE output of the USB dac works if I put the jumper to the SPDIF. Would you please explain to me what I should do?
Puzzled,
Peter
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kgodfather wrote:Hi,
The SE output of the USB dac works if I put the jumper to the SPDIF. Would you please explain to me what I should do?
Puzzled,
Peter This is normal. Enabling the Analog output of the USB DAC module itself requires that either you connect DO to DI or have SPDIF output enabled selected at the format header. It sounds like you have an issue with the I2S signal, this could be at the source or at the DAC. Check continuity between the I2S terminals on the Opus DAC and the USB module. Edited by user Tuesday, July 14, 2009 7:12:09 PM(UTC)
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Hi Russ,
Here is what I checked.
1. Resistance around the I2S connections: I checked the resistance between the two soldered points (one from the USB, and the other from the Opus). I found all values to be less than 0.3 ohms.
2. DC Power supply: I checked the input voltage of the LCDPS to be 7.50 V on both of them.
What shall I do now to check further? Can I feed SPDIF to the Opus DAC? What shall be the control settings on the OPUS side?
Just as a side note, I wired the output of the OPUS directly to the XLR male connectors.
Thank you,
Peter
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