I just built up an amp with 2 1500uf caps in parallel (41hz amp4) for the reserve caps. Im powering it with an external 24vdc 250watt smps with an 80mv ripple meant for plc's. I have a 5-8khz noise coming from the speakers that i can hear from a foot away, regardless of source.
Is there something i can do to remove the noise? Maybe a clc or crc filter?
Is there something i can do to remove the noise? Maybe a clc or crc filter?
Maybe it's the difference frequency between the carrier and some of the harmonics of the SMPS.
But nightanole could try to load it with a constant 10 W to check if it's a burst mode operation.
In most cases the grounding/shielding system is the culprit, not the SMPS alone. Try to alter things, and watch the result! As an experiment try to remove every unneccessary things (input selector, volume pot, even the input cable, short inputs instead)! Try to move SMPS away or closer! Etc...
In my experience the extra supply rail filtering never helped (at least in a single amp modul system), but you can try it also.
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