Anyone who owns a Technics SU-R1000, can you answer a quick question

I’ve been getting familiar with the new SU-R1000 for the past couple of weeks and I’m thrilled with it so far. Selling all my other gear, sounds amazing, couldn’t be happier and all that jazz.

But I am wondering if anyone here who owns one can answer a question about the phono preamp noise floor?

Stereophile measurements appear to be impeccable, but I hear a definite noise floor in the phono pre, even when the source is turned off. It is a hiss that is inaudible until the unit is turned up much beyond 40 on the volume knob.

I have swapped out my Pure Fidelity table with my Technics SL-1200, optimized both cartridges, and both have the sound. When the amp is muted it mutes the sound.

It is not audible on any of the other inputs.

So if anyone else has this preamp - could it be mine has a defective phono pre input, or is it just a higher noise floor?

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Thanks all, this is not a ground issue. The issue is that only on the phono pre channel (RCA, not XLR), when I turn up the sound beyond a certain threshold, there is a “hiss” noise floor not unlike a tube amp. It’s not a 60 cycle hum or a buzz or noise. It’s just not a “black” noise floor like all the other channels. It also goes away when the unit is muted.

The Line In input has a totally black background no matter what the volume, as does the digital input. 

The hiss is there whether I turn on or off the subsonic filter, crosstalk filter, or cartridge optimizer. 

It’s also not audible when music is playing. The R1000 does seem to accentuate surface noise a bit with its digital processing but this is not record surface noise, it’s just a “not-black” noise floor that is almost like a gain staging issue when you are turning up gain but input is not very high. 

It’s definitely “live with-able” but I was wondering if this was a factor on all units or just mine. I have to turn it up beyond 40 to hear the hiss.