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

This sounds like a ground issue. 

Did you turn on subsonic filter button?

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.

The question that remains unanswered is when you are listening to the RCA input phono section “hiss” is the amp set for a MM cartridge input or the increased amplification factor of a MC cartridge.  I do not find the actual amplification in the R1000 specifications.  Many MC phono amplifiers with 60db to 72db amplification factors can have a more present noise floor when no signal is being put through them.  It could also be present with the MM setting which is usually around a 40db amplification but probably not as present as when MC is selected.  

Definitely a gain issue what's the output of your cartridge? And does the Technics have adjustable gain settings for phono?