SUT help

Different SUTs apparently can sound different from one another, even when they are the same with respect to turns ratio (i.e., the amount of voltage gain added).  This can be due to the nature of the core material (the transformer wire is wound around a core; there are many different choices for core material, and I am not equipped to discuss them), the nature of the wire used (purity of copper or silver or silver plated copper), the input and output jacks per se, and the interconnects that must be added into the signal path in order to install a SUT.  If you think that's a virtue or that you can make it a virtue, go for it. I am sure a transformer manufacturer can list still more factors that affect SQ.

I watched the video. The SPU 1 cartridge puts out 0.18mV, by a very liberal criterion of 5mV/cm stylus velocity. The JC3+ affords 64db total gain on MC. Could be that the amplified output of the JC3+ is not quite enough to get the most out of the downstream sound system. (The signal voltage output would be about 0.27V, not by itself enough to get the most out of most amplifiers.) Could be the JC3+ has an inherent lean sound on MC settings. Could be his ears. Anyway, for sure a SUT is an option.

Pindac,  I know nothing about your phono stage and certainly never said or even implied that it was inferior. Originally, I was merely asking about how the term "Transconduction" might apply to the mystery phono stage that you like. The way you used the term, it seemed you were suggesting it is a category of phono stage opposite to a "Transimpedance" or current driven phono stage. To me, the alternative to current drive is voltage drive, and there is no need to adopt the term transconductance because in fact all audio gain devices act through transconduction.  Then you revealed finally that your phono stage at least starts life as a Paradise phono, made on a custom basis in the UK, so far as I can tell.  I read something about it and commented that it received a lot of favorable mention on the internet, and that it appears to use an FET and a tube complement that are both reminiscent of the Herron phono stage that is much liked on this side of the pond. Please show me where I criticized the Paradise phono, on any basis at all, let alone its relatively low cost. I also never in any way said that cost is directly proportional to results in audio.  It most certainly is not.

Pindac, what a pile of rubbish!

Pindac, I have no doubt that what you say is a true summation of your personal experience. I can only suggest that maybe you haven’t sampled some of the very best high gain phono stages. This is not to say that I would argue the superiority of any single approach to amplifying LOMC cartridges. Also, I might point out that a “head amp” either voltage driven or current driven is naught but an outboard gain stage that mimics the gain characteristics of a good high gain MC stage, which puts everything in one circuit without the necessity for a separate chassis and an added pair of ICs.

Elliot, The phono stages in both of my phonolinepreamps have sufficient gain to handle any LOMC cartridge. I am going to generalize and say they both produce a total gain (including linestage gain) of more than 75db, probably more like 80db. They are both fully balanced designs. (One is my modified Atma-sphere MP1; the other is Raul’s 3160 Phonolinepreamp which can be configured for either of two levels of MC gain.) No MM stage is involved. 80db applied to the MC2000 output is enough gain to drive my Atma-sphere amplifiers with room to spare, and the amplifiers drive Sound Lab 845PX speakers which I have modified to make much more efficient than stock. To the OP: I have no beef with SUTs. I have heard SUTs do a fantastic job paired with an excellent MM stage. I just chose not to go that route. I can’t even give you a good reason why, except maybe I am a cheapskate.

I've experimented with "transimpedance" stages, and I prefer the above two preamplifiers to what I have heard in my system.  Let's call them "current driven", not transimpedance, because the latter term implies that impedances make no difference. They do, or it does make a difference.

Ralph, You should know by now that in my case you are preaching to the converted. I do not now own a SUT. Nor have I ever owned one. Furthermore, except for one amplifier I built myself from scratch for the fun of it and because I came into a pair of fine vintage output transformers, I have never used a transformer coupled tube amplifier. But all that is part of a personal belief system that I keep to myself (except for now), and I would not foist it on anyone else who likes to use a SUT.

I also now have two very fine phonolinepreamps (to use Raul's parlance), one basically tube and one all SS, both of which have sufficient active gain for any MC on the planet, which is to say the Ortofon MC2000 at 0.05mV output can be accommodated by both with no intercurrent audible noise.

Elliot, So, to boil down what you wrote, your FR SUT used with an LOMC cartridge, has no effect on the overall SQ of your MX110 used straight in with an MM cartridge, even taking into account that the two cartridges themselves are different from one another in SQ, like tonal balance, bass accuracy, etc.  Would that be a fair summary of what you wrote above?  Because I am on your side; a SUT, like any other component of an audio system, ought to be as neutral as possible (even though nothing is neutral except subjectively).

In my opinion, if you are dissatisfied with the SUTs that are built into the Modwright, you ought to talk to Modwright about having them install a better pair of SUTs. You would have pretty much the same array of choices, you probably will save money because you don't have to pay for the box that houses the SUTs, you probably gain some advantage over any external SUTs in that you avoid another set of RCA connectors and wires with capacitance in the signal path, It's a win, win, win proposition.  After all, Modwright made their bones by modifying gear built by other companies; surely they can do the same for their own gear.

Either “handy” or superfluous.

This is very simple, besides the fact that you don't need a SUT.  You can use any SUT with a 1:10 step up ratio.  That means the signal voltage will be increased 10-fold, to 4mV with either of the two cartridges in question. That is easily enough signal voltage to drive the MM section of your Modwright, set to even 40db of gain.  If that seems a tad lean, you can use the 46db setting, but the 52 db setting is definitely overkill.  (The phono gain needed is somewhat dependent upon the gain added by your linestage, if you use an active linestage, the input sensitivity of the amplifier, and the efficiency of the speakers.) The load seen by the cartridge is the input resistor of the MM phono stage divided by the square of the turns ratio.  If the Modwright has a  typical 47K resistor at its MM inputs, then the cartridge sees 470 ohms (47,000 divided by100).  That is absolutely fine for either cartridge.  This is all you need to know.