Phono Stage Hum

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

Might be the nature of the beast. I have the 9A and also have a low level hum. It is not audible unless it is very quiet or I put my ear to the woofers. I have tried all the suggestions mentioned above with no luck. Play with your cartridge settings as I was able to reduce, but not eliminate the hum.

On the Jolida: There is a high output and a low output. Both seem to be line level. I have been running the high output to my integrated. Maybe I will run the low output to the integrated, and then set the gain for the MM cartridges. That might be the best way to start.

In the manual, it says that the "low" is for preamp separates and the "hi" is for integrated amps or line stage preamps. That is why i have been using the high.

I just pulled the phono cable out of the phono pre. I still get some low level hum (actually a noise more like wind blowing across a mic) but I have not put the shorting plug in yet. That strikes me as potentially noise around the tubes.

One more update:

-I ran the turntable directly into the phono stage of my Creek 5350 SE. No hum.

-I then ran the turntable into the JD 9A and the JD 9A to the Creek. Hum.

It seems to me that it is clearly something in the phono preamp. Right? or in the connections/settings.

Off to play around with the placement and settings on the 9A.

Tim

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.