Ideas for noise reduction

[DragonMaster]

To reduce noise level for any synths there are important things to remember : clean PSU and good opamps. (I am suscribed to forums including many audiophiles so the following ideas might be too expansive or maniac)

Clean PSU:

while 78xx are simple, they are pretty noisy. Using better variable regulators is better in this case. Look at the PSUs here : http://www.tnt-audio.com/clinica/tnt1541_e.html they're quite complex.(I'm building this project, but I'm not maniac to the point of buying 2$ resistors, 0.09$ will still do the job) Separating digital and analog circuits can also help. Clock and PIC noise is not introduced in the signal. Since the SID is affected easily by signal noise(From what Yannes told in "the" only interview with im avail. on the Internet), it should have it's PSU separated from anything else(Or at least it's own regulator with ferrite beads in front).

Good opamps:

If you're really a noise maniac, you will find that TL0x4 is pretty noisy. In this case give the opamps their own PSUs and put OPA4134 opamps instead.