Hello all, this is my first post here, I mostly hang out on the Audio Asylum. I recently aquired a SB3 and have started using it in some unusual ways.
I've been building my own DACs for a couple years now and have really gotten to dislike S/PDIF with a pasion, which why I've been doing USB DACs for awhile. The SB line has intrigued my for quite sometime, particularly the fact that the out is controlled directly by a crystal with no PLLs in the path, this can result in some very low jitter implementations. As an aside I've actually been using slimserver for a year and a half, feeding a small no moving part PC running linux with softsqueeze sending USB to my DACs (long line of evolving hardware). But I hadn't actually bought the slim hardware yet. I finally got an SB3 a couple weeks ago and was quite impressed with it. The analog outs are actually pretty decent, no not as good as my DAC (which uses PCM1704s with no digital filter driving a discrete output stage and buffer of my own design). I haven't tried the S/PDIF out, since I don't like S/PDIF my current DACs don't that input and my old stuf that does isn't anywhere near as good as the current designs, so I didn't even bother. No to the real reason for this: hooking up the I2S from the SB3 directly into my DAC, bypassing S/PDIF and using a very low jitter clock in the DAC. I used an 11.2896 Tent clock with very low noise regulator to feed both and internal synchronous reclocker in the DAC and also the SB3. I took out the 11.2896 crystal and fed it from the DAC. The I2S signals travel over a short ribbon cable to the DAC where they go through a CPLD which does the I2S splitting tasks since the 1704s are mono. The output from the CPLD goes to the reclocker which is just a set of flip flops, its not changing the data or the rate in any way. Thats the beauty of the SB architecture, you can feed in an extarnal clock so it stays in sync with the external clock in the DAC. Well the results were very promising, significantly better than anything else I had ever done, BUT my ears hurt after listening to it for more than a few seconds. This usually means there are some very high frequency signals getting through. At first I thought it might be the SB3 since the spectrum analyzer showed strong peaks in the very upper trebble, but Sean said they don't do any EQ, that effect in the analyzer was just for looks. I finally tracked it down to my unshielded interconnects picking up EMI from the SB3. It wasn't quite as bad when playing the analog outs since the cable exited straight out the back. With the I2S output I had to have the SB3 very close to the DAC, the entry for the cable was right next to the output RCAs so the ICs picked up a lot more. Some very good shielded ICs fixed the problem. Its now back to sounding awesome and I can stay in the same room with it! The quality of sound from the combo is just incredible its way more alive sounding than any other digital I've heard. An intereting artifact of this is that with the Tent clock feeding the SB3 the sound from the analog outs is significantly better than it was stock. The only other thing I have done to it is run it off a good linear supply (whih does make an improvement), but going to the Tent clock made a much bigger improvement than the external linear supply. And this is with the stock output stage, no changes to it yet. I think this technique of slaving the SB to an external DAC clock is definately the way to go for ultimate digital sound, much better than anything else I've heard. I guess thats enough for now. John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=24800 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/lists/listinfo/audiophiles
