phono pre loading and gain question


I have a Motif mp-11 phono pre. Inside, through switches, the gain can be set between 40, 45, and 48 db. On the front is a knob selector for loading with positions: 70 ohm, 100, 150, 250, 470, 1k, 2k, 5k, 10k, 20k, and 47k. I have read most of the threads and am still confused about how low of an output mc I can use. This feeds into a Sonic Frontiers preamp with 20db gain. I don't want to get a step-up transformer if I don't need one...but I would like to try a Shelter cartridge out. Also, why would my phono pre have so many loading choices but so little maximum gain. One more thing...are step ups very prone to noise or hum. thanks
skeyebox
I now use a phono stage with 45dB gain in MM configuration in conjunction with an internally wired Lundahl LL9206 step up transformer set at +20dB gain for MC. I have a Shelter 501 MkII pickup.

When I ran it through a passive linestage (no gain) and into a McCormack DNA-225, 30dB gain, I experienced very good performance, indeed. I tried this setup with and without the step up and found greater dynamics when using the additional 20db gain, As such, I can see where Tom feels that Skeyebox might be teetering on the edge with respect to gain and the Shelter. As a side note, I find that, in my system, the Shelter sounds much better on most recordings when loaded at 300ohm, as opposed to the 100ohm recommended by Shelter. For some reason, the sound is generally just a bit thin when loaded at 100ohm. Too dumb to know why, just know what I hear.

I have used the same phono stage running through a linestage with 14dB and, of course, have more than enough gain and, in fact, am thinking of dialing back a bit on the MC step up.
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Well, my amp is very low power, maybe I don't have alot of gain there, so I need to get it earlier in the system. I don't have a gain spec on my amp. Heck, all I know is that is what it takes to sound good in my system.
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