Hi, previously my stock crack had a slight audible hum. I tried resoldering every joint with new solder and cleaned all the pins. Used bigger caps but the issues remained. Surprisingly when I changed the power supply diodes to a single package vishay bridge rectifier the audible hum was gone, well at least with hd600s. But when I use the 600ohm beyerdynamic dt990 I can again hear the slight hum although not as noticeable as before. Same with high impedance iems. The hum does not change with the volume knob. The magnitude remains same no matter how much I turn the volume knob or change the dac volume. My mains frequency is 50hz.
Is there any solution ? Or this is just normal for crack ? Any suggestions are highly appreciated.
Thank you.
