Atma-sphere MP-3 Mk III vs Alnic L-10000 OTL linestage + Allnic phono aotl

I had both units Mp3 and Mp1 in my set up.   Using stock tubes or aftermarket NOS, no way i can say that the Atmasphere Phono section works on Low MC.  Balanced cables or Rca single ended, whatever choice of cables ( i tried them all).  It gets worst when the cartridge is low at .25mv ( according to the manual, it’s doable for low mc) all you hear is tube noise rush.  That is from my own experience and honest assessment!

We show at audio shows with Dynavectors and the like that only have 0.25mV and don't seem to have any problems (we got Best Sound at Show from Dick Olsher with exactly that cartridge). The cartridge that we use in the shop is only 0.25mV and it seems to work fine.

So I suspect you've been using noisy tubes without realizing it. It could also be that your tonearm cable isn't set up properly; certain hookups will cause the phono preamp to be quite noisy because the cartridge isn't presented to the input of the preamp correctly.

I had an atmasphere mp-3 over a year and then upgraded to an mp-1, For the money it is hard to find something better than an mp-3 for both analog and linestage, excellent preamp, the phono stage if you have RF around your place or EMI sources and you are not not using a good phono cable could pickup some external noise, the phono stage is designed around gain and it is hard to keep quiet if you are not using the proper interconnects or tubes, I loved my mp-3.

If you use a high gain MM cartridge you might want to use gain attenuation plugs which are inexpensive from Ralph, I ordered some for my mp-1 phono stage, that’s the way you would switch the preamp between high and low gain.
Edit 1 - I have a truly balanced system using balanced pre (damn autocorrect always typing pee) and balanced amps, but I have tried single ended amps with no issues as long as the interconnects are properly build.