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
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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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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.
I never used a T-3000, so I have no personal experience with it. I have heard it is a very nice unit. Make sure it has the gain you want, and the loading selections you want.

Another choice that is good, is the EAR MC3 step up transformer.
Any suggestions on a step-up? There is an Ortofon T-3000 for sale will that work with most lomc? Thanks
Just to add more of my equipment. (and thanks for the help)I have a Sonic Frontiers Power 1 connected with balanced cables to the Sonic Frontiers Line 1 and all that goes into Infinity Overture 3s which have a sensitivity of 93-94db.
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To add to Plato's point, I have 100db speakers and my amp only requires three-tenths of a volt input to reach max output.
On the other hand, unless the amplifier input is very sensitive (like the Monarchy Audio SM-70) and the speakers are very efficient (maybe 95 dB/watt or better), TWL is probably correct that the 68 dB of overall preamplification would not provide adequate volume levels with the Shelter 501.
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.
Marty,
Sorry to but in on Tom's possible answer, but without knowing the input sensitivity of Skeyebox's amp and the efficiency of his speakers and the size of his listening room and what average listening level Skeyebox personally prefers... Who can say that he will or won't have enough gain with his present set up???
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With a step up transformer, the phono section would be loaded at the 47k ohm setting, and the load for the cartridge would be set at the input of the transformer, at an amount about 1/2 what is suggested as the normal load for going direct in to the phono stage, unless there is some specific directions by the manufacturer of the cartridge that it should be loaded at "X" for direct input, and "Y" for transformer. Some cartridge spec sheets will specify the loadings for both direct input and transformer.

I use a Shelter 501 with a step up transformer, and find that it works very well at a transformer loading of 40 ohms.
Thanks for the response...but if I use a step-up then I just leave the loading on my phono pre on 47k?
You'll be about 15-20db short on gain for a Shelter, with that setup. The loading choices are an entirely different matter than the gain amounts. The loadings are to properly provide the cartridge with the correct characteristics that it is meant to drive. The gain settings are to increase the output of the cartridge to a useable level for the preamp to accept. Both are important to get the best from the cartridge.

Step up devices are not inherently noisy, but some cheaper head amps might be. Transformers may have some rolloffs or bass problems if you don't get a good one. The key is to buy a quality one of whatever type you choose.