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Phono Stage Hum

I have been experiencing hum on the input from my phono preamp. In the past, any problem like this has typically resulted from a ground issue, but the ground seems to be well grounded. The hum/noise starts somewhere around the 25% mark on the volume.

The system:

KAB modded Technics 1200 w/ Audio Technica 150 MLX Cart.
Zu Xaus cable
Jolida JD 9A phono stage (high output line out)
(I have it set to no gain, but to the impedance to match the cart.)
Zu Gede
Jolida JD 102B Integrated

I have a second system that I can run my turntable through to trouble shoot. I don't get any noise over the line from my DAC (fed by my cdp and my digital library).

Any thoughts as I start the troubleshooting process?
tjnindc

Showing 2 responses by mapman

mapman's avatar
mapman
22,634 posts
 
Check all connections including those to the cartridge first.

If still a problem, check proximity of the phono stage to other components and any other devices emitting magnetic fields. The power amp is a prime suspect. Move it around physically and see if hum increases/decreases. Try to locate it where hum is minimized or hopefully gone.

If that is it, I have been treating a similar issue with my phono. Check my system postings for more info on solutions involving adding additional magnetic shielding, if needed.
mapman's avatar
mapman
22,634 posts
 
The phono pre-amp seems to be the suffering piece.

Hopefully it is just external magnetic fields that can be taken out of the equation (like kryptonite with SUperman) rather than some inherent problem with the piece itself.

Good luck.
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