wayne325;558884 Wrote: > > > What did you find for oscillators and how did you source them? > >
The original versions used Tent clocks with low noise IC regulators. The current versions use Silicon Labs 530 series oscillators which are rather unusual. They are actually frequency synthesizers with internal crystal reference. Several companies do this, but these have unusually low jitter. Its quite a bit better than the Tent clocks. You can get a 7ppm version from Mouser for $20. You'd be hard pressed to find any traditional oscillator for that price that sounds better. If you want to spend quite a bit more, yes you can do better. Since its programmable you can get it in any frequency you want. Mouser doesn't actually stock them, thy are custom programmed, but the turn around time is very quick. They also have one with external programming pins, you can change the frequency on the fly. With this you can make a really high quality frequency tracker (I hesitate to say PLL because I would never use it for that tight a lock). The jitter is just as good as the fixed one, they do cost more though. I'm actually working on an FPGA controlled one of these this week. I have a board all up and running, I just need the small matter of he FPGA configuration to sense the buffer and modify the frequency of the oscillator appropriately. I have a DAC with a S/PDIF receiver implemented in the FPGA, no PLLs or any such. This assumes that the source is already synched to the local clock. With this and the adjustable oscillator I should be able to sync to any source and produce results close to what I can get from a true feed the clock back to the source scheme. It will be interesting to see how well this works. These oscillators eat power like it going out of style. The fixed frequncy ones take about 92mA and the adjustable one is over 100mA. Even though its not officially oven controlled, the guts get hot enough that it almost is. I would never turn the supply on and off to these. The behavior changes enough as they warm up that I just leave them both on all the time. I also have several supplies: one for digital stuff, one for clocks, one for DACs, and one for analog stage. (current one is also JFET discrete). MANY discrete regulators. I use designs with LEDs as voltage references, some red, some green. The thing looks like a Christmas display inside! Aint DAC design fun1 John S. -- JohnSwenson ------------------------------------------------------------------------ JohnSwenson's Profile: http://forums.slimdevices.com/member.php?userid=5974 View this thread: http://forums.slimdevices.com/showthread.php?t=79677 _______________________________________________ audiophiles mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/audiophiles
