Step Up Transformer

Two different things. I think you’re referring to current driven phono stages that supply all the gain needed plus RIAA correction. There is a plethora of those. I’m talking about a current driven external gain-only device that does not supply RIAA or by itself is it capable of driving an amplifier or downstream linestage. It drives an MM phono stage. IOW it’s a head amp or pre preamp that works off signal current not voltage. I only know of one such commercial device, made by Sutherland.

Another new option to consider is to use an outboard current driven gain stage to feed a very good MM stage. Sutherland make one, and I’m using one from another source that was custom built for me. Results are excellent if you’re limiting your choice of cartridge to very low output MCs with very low internal impedance. But that’s what you do anyway when you choose to use a SUT.

Not sure what you're after. Bobs Devices SUTs are certainly "off the shelf", and if you purchase one of their best SUTs, and one that is suitable to both your cartridge and your phono stage, you will probably have wide bandwidth and low distortion.

Pindac, I am not sure you directed a question at me, but if so, as regards voltage vs current, in the case of a SUT, you are aiming to amplify voltage, not current, so the fact that you lose current in proportion to the voltage gain is of no consequence to the downstream voltage driven phono stage.  The advent of current driven phono stages has muddied the water for some, but you'd never want to use a SUT with a current driven phono stage.

For what it’s worth, and that’s probably not much, a SUT increases signal voltage (not “current “), and a SUT decreases signal current in direct proportion to the increase in voltage. The product of voltage X current at the primary is equal to the product of voltage X current at the secondary side. So if V goes up by 10X, then A (current in Amperes) goes down by a like proportion. In this regard, a current driven phono input is the opposite of a SUT.

Did not mean to offend anyone. Just trying to make a point about the subjective nature of these decisions. It seems the OP has chosen a SUT. One hopes he will be happy with it, and even more than that, it will be interesting to learn how he  likes it compared to his high gain phono stage for sound quality with his cartridge. 

edgewear, Wouldn't it be more fair or accurate to say that you are the one who prefers one or the other mode of phono amplification with this or that cartridge?  (Rather than to say that the cartridge prefers a particular sort of voltage gain.) Nothing wrong with that, but we are talking about personal preference, which is always unchallengeable.  Similarly, the OP may prefer a particular SUT vs using his high gain phono stage, and that's OK too, but apart from helping him to choose a "good" one, no one of us can say what particular SUT flavor he will like.