Phono Stage Hum

Not sure what you mean by having the phono stage set to no gain. The specs at the Jolida site show 70db gain for moving magnets (which seems like a lot, btw). And I assume you have its riaa equalization in the path.

Is the hum equal in both channels?

Do you have the turntable, phono stage, and integrated amp all plugged into the same outlet or power strip or surge suppressor? If not, I'd suggest trying that, to make sure that ground offsets between differing ac sources aren't causing the problem.

Are the components physically some distance apart, so that for instance ac fields from the power xfmr and associated wiring in the integrated amp aren't being picked up through the air by the phono-level wiring.

I'm not familiar with the cables. Do they by any chance have directional markings, which might signify that their shields are grounded at only one end? If so, try them the other way.

It could also conceivably be a tube problem, such as a filament-to-cathode short.

Do you get the hum when the turntable is not turning? If not, it would suggest Grado-like pickup by the cartridge of 60 Hz emi from the turntable motor.

Also, if possible disconnect the turntable from the phono stage, and put a shorting plug on the phono input, and see if you still get the hum.

HTH,
-- Al

I'm totally confused by what the dealer told you. As I indicated, 70db phono stage gain for your 4mv cartridge does seem a bit excessive. But "no gain" is absurdly too low -- that would say that on loud passages only about 4mv would be going into your integrated amp -- WAY too low.

Also, how physically was the gain adjusted to 0 or whatever it was set to. Based on the JD9A description at their website it just seems to have 3 settings -- 70, 85 or 95 db.

Re RIAA equalization, as you may know records are cut with non-flat frequency response (20 kHz boosted around 20 db; 20 Hz cut around 20 db, relative to 1 kHz, with boosts or cuts for other frequencies corresponding to a specified curve). The phono stage has to apply an inverse frequency response curve, to restore a flat response relative to what was recorded.

The JD9A description at the Jolida site says something about "Two Outputs RIAA, Line stage." Not sure what that means, but it sounds like one pair of outputs might not have the RIAA equalization in the path, for whatever reason. If not, and if that is the output you are connected to, you will not get good sound to put it mildly (although that may be unrelated to your hum problem).

Regards,
-- Al

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