I’ve got a several dB difference in volume between channels. I’ve gone through everything and narrowed the likely culprit down to two possibilities, with the spdif run between a modified Oppo 203 and dac being the most likely, for reasons I’ll leave aside for now (the other is one of the dac’s outputs). Swapping in another spdif cable got the same result. Since I don’t have another source to sub in for the Oppo, is there way with a multimeter to check what’s arriving for each channel on the destination end of an spdif cable? Thanks,
Your problem is not very clear for me, I need more data. For to do the things like I should be, you must have a audio generator and a meter or a oscilloscope. If you don't have any of these things, you can try to download and copy a CD test with some audio tones, like Yeds18. There is some 1Khz and other tones in some tracks. Just try...
Best regards
Best regards
Then swap the RCA plugs at the DAC output, and see if the problem switches speakers.
All swapping has switched speakers for the differences. I also was able to measure 1.0V out of each of the dac's RCA outputs. That would suggest the problem is not there. However, one of the outputs was sloppily put together during a warranty repair in the U.S. -- loose nut, weak center pin, bare wires shorting -- so I'm not ruling out that might be the cause. For that reason reason it looks like the dac is going back to Poland to be checked over. Before then, I'll wire directly from the dac directly to the active speakers, bypassing the preamp, to see if I learn something from that.
I don't see how the SPDIF cable could modify the left/right balance. All the bits and bytes go through the same cable in the same way.
If swapping cables between the analog DAC out the the (pre) amp input changes the imbalance you hear in the speakers, the issue is either on the analog side of your DAC or something is wrong with the cables. Since you seem to think the DAC is fine, try different cables.
If swapping cables between the analog DAC out the the (pre) amp input changes the imbalance you hear in the speakers, the issue is either on the analog side of your DAC or something is wrong with the cables. Since you seem to think the DAC is fine, try different cables.
SPDIF cable cannot alter one channel, either it works (no bit errors) or it doesn't (random bit errors on both channels).
To know if the SPDIF signal is correct, you can use a PC or laptop with SPDIF input and simply record it and look at it in audacity. If there is nothing in your house that has a SPDIF input, you can borrow a USB soundcard or a home theater amp from a friend. If the SPDIF signal has one channel louder than the other, it's probably a software/configuration issue in the source.
You should test your DAC with another SPDIF source. If you don't own one, but you have a recent TV, you'll probably find a SPDIF output at the back. Some PC motherboards have one. You can also borrow a device like a DVD player.
Try a divide and conquer approach : you own another signal source, like a phone or a laptop, try that on the speakers and the preamp. Also try the headphone output on the preamp, and switching channels with RCA cables.
If you don't have a scope, try a low frequency sine wave like 20 Hz. You can generate the signal easily in audacity and save that as an audio file. Low frequency makes it much easier to hear the scratching from a bad contact, which a multimeter will not measure.
To know if the SPDIF signal is correct, you can use a PC or laptop with SPDIF input and simply record it and look at it in audacity. If there is nothing in your house that has a SPDIF input, you can borrow a USB soundcard or a home theater amp from a friend. If the SPDIF signal has one channel louder than the other, it's probably a software/configuration issue in the source.
You should test your DAC with another SPDIF source. If you don't own one, but you have a recent TV, you'll probably find a SPDIF output at the back. Some PC motherboards have one. You can also borrow a device like a DVD player.
Try a divide and conquer approach : you own another signal source, like a phone or a laptop, try that on the speakers and the preamp. Also try the headphone output on the preamp, and switching channels with RCA cables.
If you don't have a scope, try a low frequency sine wave like 20 Hz. You can generate the signal easily in audacity and save that as an audio file. Low frequency makes it much easier to hear the scratching from a bad contact, which a multimeter will not measure.
It turned out the best way to isolate probable causes was to pick up a DVD player at Wal-Mart and wire the dac directly to the active speakers. The result was pink noise was the same from both speakers, while from the midrange on down there was considerable difference, varying between speakers depending on the frequency. Same when I hooked everything back up. A matter of the room mainly which is not optimal, I assume.
It did. That says it’s not the speakers, which was confirmed today when pink noise readings were virtually the same. Perhaps you misunderstood my comment about variation with midrange and lower test tones. One speaker was considerably louder at some mid bass frequencies and then lower as the tones got down under 80 Hz or so.