Do I need a sut?

Anyone know about this one? Fidelity Research  XG-5 moving coil step up transformer with selectable input impedance.
Low - 3 ohm or lower 34dB Mid - 3-18 ohm 26dB High - 18-40 ohm 22dB
I know nothing about Fidelity Research and can't find out any good or bad info on this unit, it's as old as my cart.
Probably a "swing and a miss" but thought I'd ask.

The XG-5 is a pretty re-saleable SUT so if the price is right why not give it a try, you can always resell? The 34dB/3 ohm setting would work

Remember to budget for a quality pair of interconnects (of low capacitance as Al notes)

There's more helpful guidance including specifics on this model here
https://www.vinylengine.com/step-ups-and-mc-cartridges.shtml

I found one that's not pretty, but  a super price. It's worth a try, let you all know what I find out, it will be a few weeks(coming from off shore)

Thanks for all your input

Jeff

I think Al has it pretty much summarized.  Most transformers are intended to be used in front of a standard MM gain stage, for two reasons:  1) matching of gain, and 2) transforming of load. A MC stage typically has an input impedance of around 100 ohms. A MM stage typically has an impedance of 47k ohms. Remember, the transformer doesn't just STEP UP, it transforms from a low-impedance, low voltage to a high impedance high(er) voltage.  You need to match impedances as well as levels, and the 100 ohm MC stage would just bog down the transformer - it would effectively be driving a short circuit.  I bet your MC stage can be configured as MM.  All mine are - same basic circuit, different loads and gains.

Thanks, Itsjustme!

To clarify regarding the Herron VTPH-2 specifically, the input stage it provides for LOMC cartridges utilizes a FET (Field Effect Transistor). Consequently, as I mentioned earlier, it has an input impedance that for practical purposes is essentially an infinite number of ohms, but it provides connectors on its rear panel for purposes of connecting loading plugs. 47K loading plugs are supplied as standard with each unit, and Keith Herron can supply plugs in any other values that may be desired. He recommends that with many and perhaps most cartridges the VTPH-2 will provide best results with no loading whatsoever, and I and some other members here have found that to be true with our particular cartridges. Even though, for example, my AT-ART9 has a load resistance recommendation from the manufacturer of "100 ohms minimum."

As you may have seen in the past, Ralph (Atmasphere) has stated in a number of threads here that the need for relatively low impedance loading, where necessary, is mainly due to sensitivity of the particular phono stage to RF frequencies, which can be introduced into it at significant amplitudes as a result of the resonance that is formed at RF frequencies by the interaction of the inductance of LOMC cartridges and the load capacitance that is applied to them. Apparently the VTPH-2 can handle RF frequencies in a more graceful manner than many other phono stages, meaning that such frequencies will have little if any effect on audible frequencies.

So as I had mentioned interposing a SUT between an LOMC cartridge and the LOMC input of the VTPH-2 can be handled in a reasonable manner from the standpoints of cartridge loading and transformer loading. But the concern that would arise in this particular case would be the possibility of a voltage overload in the phono stage and/or in whatever preamp circuitry may be "ahead" of the volume control.

Best regards,
-- Al