Sean, thank you for the tests, I had not intended this to get into an adversarial issue, I'm just trying to find out whats going on here to get the best sound.
I appologize if I have "cast aspersions" on you or your products that has not been my intent. In order to try and get to the bottom of this I took everything all apart and rebuilt it and reinstalled software etc. All the following is with the low jitter clock in the DAC feeding the SB3 and the "I2S" lines going into the DAC where they are split(taking into account the left justified format), reclocked by the low jitter clock and fed to the DAC chips. The resultant jitter is somewhere at 10 or less ps(its vert tough to measure down there) With some single frequency wave files at various levels and frequencies I get exactly the same output as with the same files sent over USB (but much lower jitter). With music files I get mixed results, some have the same volume as USB and some are lower in volume. This was done using a peak hold feature of the peak to peak measurement in the scope. I finally tracked this down, it was due to replay gain. It turns out that the installation of slimserver was not preserving settings, so even though I had set replay gain to disable, the next time it started it went back to "SMART GAIN". Some of the music files had gain tags and others didn't, thus causing the disparity. Due to switching back and forth between SB and USB inputs I had to reeboot the computer often and did not explicetly check all the settings every time slimserver started up. BTW the "preamp gain" doesn't seem to affect the bits going to the DAC chip, it must be implemented in the attenuator builtin to the DAC chip. The "not sounding as good" issue turned out to be EMI coming from the SB3. Because the cable between SB3 and DAC is very short they have to right next to each other. I tried a test where I was running data over USB and turned on the SB3 and played music through it, this caused the "degradation" even though the data was not coming from the SB3. Wrapping the SB3 in aluminum foil got rid of the problem. It didn't even have to be grounded. It does make it difficult to read the display. In the unwrapped mode I tried different display brightnesses and different screen savers and could hear no difference, it doesn't seem to be a display issue. The upshot is that I'm now listening to a rather interestingly styled, very brightly shining, SB3 with replay gain turned OFF, with very low jitter going to my DAC, the results are stunning. Sean, thanks for puting up with me while I worked this out. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=26002 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
