QSXM3 hum problems

[peranders]

Glad it all turned out well. Wiring is a serious business! Please do send some photos.

[peranders]

I have checked your pictures and so far I have hte following comments:

All skrews should be insulated so the groundplane is connected to the chassis only in _one_ single point, preferrable X1 and pin 3, "chassis".

The cartridge should be connected with a shielded wire from both inputs. The turntable you have, has probably a separate ground for each channel.

Otherwise it looks very tidy and nice.  :D

[rcgomes]

All screws are insulated both from bottom, and from top with rubber o-rings.

I'm now using shielded cable as you advise.

Thanks for every thing.

PS- does this unit benefit from changing the 7815/7915 for your speacial regulators?

[peranders]

PS- does this unit benefit from changing the 7815/7915 for your speacial regulators?

It might be the case but used opamp has pretty good PSRR. If I had designed the amp today I may had made it differently but having R+C+R+C+R+C+R+C+R+C+R+C in front of the regulator is a positive thing in order to reduce hum and after the regulator I have 2.2 ohms + 470 uF which reduce the regulator noise.