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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
almarg's avatar
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almarg
9,670 posts
 
See this recent thread for some ideas about what to try with respect to the radio signals:

http://forum.audiogon.com/cgi-bin/fr.pl?htech&1230309974

HTH,

-- Al
dubhouse
19 posts
 
It might be those Zu Xaus cables. Are they shielded?
tjnindc OP
91 posts
 
The Zu Xaus is shielded. I think that I need to:

1: Play around with the cable from the phono pre to the integrated.

2: I've heard that using a three to two prong adapter on the phono pre power cord at the power conditioner can help.

The problem is volume sensitive. That leads most to think that this is not a ground issue. I don't always get the radio broadcasts which is strange but also seems to support the idea that it may be driven by external interference. I guess the challenge is figuring when it is introduced.

I've swapped the cartridge to confirm that makes no difference--it did not.

Any other thoughts? Anybody know the acoustic revive equipment?

Tim
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