Marty, I have the Shelter and I use a Cotter step-up with 20db gain, a phono stage with 46db gain, and a line stage with 20db gain. That adds up to 86db gain, prior to entering the amplifier. I think that I am running a little "hot" and could drop back to about 80db without compromising anything. But I think that cartridge really needs about 80+db total gain in the front end before going to the amp.
You can do with less, but then you have to crank the volume, and raise the noise floor with it. I have also found that when you try to run the Shelter with too little phono gain, it suffers dynamically and sounds lifeless. I tried going direct into the phono stage and eliminating the 20db gain of the Cotter, and found it totally unsuitable with only 66db total gain in the front end. It was "dead" sounding that way. I put the Cotter back inline, and it was great. No contest.
You can do with less, but then you have to crank the volume, and raise the noise floor with it. I have also found that when you try to run the Shelter with too little phono gain, it suffers dynamically and sounds lifeless. I tried going direct into the phono stage and eliminating the 20db gain of the Cotter, and found it totally unsuitable with only 66db total gain in the front end. It was "dead" sounding that way. I put the Cotter back inline, and it was great. No contest.