Increasing a Low output MM

I did not say that MI cartridges are universally unsuited to a SUT. True low output MI cartidges (let’s say <1.0mV) will still have about 100X more inductance than a LOMC of similar signal voltage output, but of course they can usually be mated to a SUT. In the case of SoundSmith low output MI cartridges, I would seek the advice of Peter Ledermann. (What privately puzzles me is the attitude of some, not you, Doggie, that one ought to find some way to use a SUT in the phono signal path, on the notion that SUTs are in some way magical.) High output MI cartridges, like B&O MMC1 and MMC20CL, Acutex LPM320, and etc, are among my favorite cartridges ever.

I guess if you could get someone to build you a SUT with a 1:2 or no more than 1:4 turns ratio, that might work. But I think it would be as costly as acquiring a different MM phono stage with more gain.

Hello, doggy, but this is an MI with an output of 2.4mV.  Which has commensurately higher induction than either of your cartridges are likely to have, since for an MI, votage output is proportional to inductive property, and again, the total gain into the MM phono stage would almost certainly be overload the input.  Those were my points. Sheesh!

Go and eat that pudding, if you like.

Sorry. "Oberon", not "Overon". Like the character in Midsummer Night's Dream.

There are several reasons why it would not be a good idea to introduce a SUT in the OP’s system. First, most commercial SUTs offer about a 10X voltage gain. If you increase the voltage output of the OP’s cartridge by 10X, it would be ~25mV fed to the MM phono inputs. That would be more than enough to overload the circuit at least on anything approaching a transient. Second, the SoundSmith cartridge is an MI type, not an MC type for which SUTs are most suitable. MI cartridges, especially high output ones, have about 1000X higher inductance than a typical MC and thus do not do well with the net input impedance you would get if you interpose a SUT.

Overon. No. Don’t consider a SUT. 

Just so we are all on the same page, I would not categorize the SoundSmith cartridge with an output of 2.4mV at standard velocity to be a "low output MM" cartridge. The output IS slightly lower than what one typically expects from an MM (~5mV), but there are truly low output MM cartridges that better fit the acronym, LOMM. Like the Stanton 980LZS at 0.3mV, and several others. So the situation is that we have an MM phono stage with lower than average gain, if average is greater than or equal to 40db, coupled with an MI cartridge (not even MM) that has low-ish voltage output compared to a typical MM (6db below a typical MM). Any good MM stage with a true gain of 40db (but a bit more is better) would work. You definitely should NOT need a head amp like the Marcof or any of several others (for instance Sutherland or Hagerman Picolo) for this dilemma. I agree with others who suggest replacing the Leben with a more typical MM stage that provides ideally at least 42-44db gain.

+1 for yogi and mulvie. No self-respecting MM phono stage would offer only 28db gain, is an editorial opinion. But if you love it, and if your linestage doesn’t help enough, add an upfront gain stage. Not a SUT.

Actually not if you’re feeding an MM phono stage that provides the RIAA correction. But I agree it would be nice to know the name of the cartridge: Input impedance would have to be tailored to the cartridge specs.