JohnSwenson wrote: > Actually the regulators I'm using have 60db PSRR out to over 3MHz. The > clocks and DAC chip have separate regulators. I haven't done a full > analysis of the power at different points (haven't had the time!) I > should do that soon. > > John S.
I use Belleson Superpower (super regulator) which has >110db PSRR out to over 100K. It is still not enough to filter the switching noise from the digital ICs, especially when powering an ultra low jitter clock. I added LC filter in front of the super reg to block RF currents, and now and it seems to do the trick. I use a 1uH non-magnetic inductor and a 1uF acrylic film cap for the LC filter just before the regulator. In my designs, I no longer use any X7R SMD ceramic caps, even for IC decoupling. They are bad to the sound (i.e. piezo-electric effect, non-linearity ESR vs freq, etc.) I now use SMD film caps. Mostly 0.1uF. They do wonders to the sound. I have a few rules in audio designs: 1. Do not use ceramic caps unless it is C0G/NP0, use SMD film caps if all possible, 2. Use digital IC chips that has the lowest power possible, less di/dt, all to the better sound, 3. Try not to use any component that is magnetic (including resistors), 4. Use non-magnetic inductors to all Vcc pins of IC chips if all possible to block RF currents, 5. If LPS is required, use silicon-carbide Schottky rectifiers. Huge improvements in the harmonics structure of the sound :) ------------------------------------------------------------------------ Kuro's Profile: http://forums.slimdevices.com/member.php?userid=16701 View this thread: http://forums.slimdevices.com/showthread.php?t=97881 _______________________________________________ discuss mailing list discuss@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/discuss
