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 shall, thank you. I was replying to your statement:

Second, the SoundSmith cartridge is an MI type, not an MC type for which SUTs are most suitable.

You are, of course, correct that a 2.4mV output would be increased far too much by a typical SUT, but I can't let the suggestion that MI cartridges of any output are unsuitable for an SUT stand unchallenged.

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.

Mind you, the proof of the pudding is in the eating, no? I have two low output MIs (0.4mv and 1mV), and prefer them both through a SUT rather than the MC input of my phono stage.

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. 

Consider a step-up-transformer. Come in various flavors, some even adjustable (Zesto). I have the latter, and gives fuller sound, though introduces a bit of transformer hum. So I have to chose between tube hiss from EAT eglow petite PS, or transformer hum from SUT. Cart is Aphelion 2 (also have a SS Zephyr, but have not mounted that on the new naia yet).

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.

@mdrone 

I am curious to lea4n, did you buy the Leben phono or end up going with another phono? 

Dear @mdrone  : Do it you a favor and don't put any $ on your phono stage is, is not woth to do it and a waste $.

Instead invest in a new unit as this one, please read the overall review including the measurements ( important. ):

https://www.stereophile.com/content/ps-audio-stellar-phono-phono-preamplifier

R.

Now that I look more closely at the cited phono stage -- as others are saying, this Leben RS - 30 EQ is spec’d at only 23.5dB gain, which is way too low, crazy low. I personally avoid MM stages below even 40dB. However, the picture gets much more rosy if we check out Stereophile’s actual measurements of a review unit:

The RS-30EQ phono preamplifier offered a voltage gain of 37.1dB, which is very much higher than the specified 23.5dB but is appropriate for moving-magnet cartridges.

37dB is serviceable. You may still desire for extra gain when using a lower output MM or high output MC (below 2.5mV), but it’s workable. The Hagerman Piccolo I previously suggested has a lowest gain setting of 12dB which would add up to 49dB -- a bit on the high side, but could be beneficial over 37dB in certain cases.

Unfortunately when we read a bit deeper into the Stereophile article the picture gets a bit less rosy again:

The wideband, unweighted signal/noise ratio, taken with the input shorted and ref. 1kHz at 5mV, was modest, at 40.3dB left and 43.9dB right, mainly due to some residual hum components. These ratios improved to 65 and 67.7dB, respectively, when A-weighted.

That’s poor signal-to-noise performance for an MM stage, much less one on the left side of the MM gain bell-curve. Adding an active head-amp gain stage will just make this worse. You might just try the phono stage as-is and see if your line stage + amp gain can cover for it. Given the measured performance of this unit, I think it would perform best with very high output MM’s 4mV - 5mV+. I know the Ortofon 2M series has a very high output level; I don’t know of others as I mostly stick to MC’s.

Stereophile reported high overload margins for this unit, which is good -- that means it should be able to take high output MM's, or medium output MC's plus a 10x - 20x SUT ratio, without distorting. If this phono stage had low overload margins, it would have to be considered a failed product. 

@mdrone as you have a Soundsmith cartridge you may wish to consider a Soundsmith Phono. https://www.sound-smith.com/phono-preamps/soundsmith-mcp2-phono-preamp.

I’m using an MCP2 MKII with my Zephyr MIMC on my Gyrodec w/ SME M2-9-R tonearm and I’m very happy with it. In all honesty I expected this little SS phono to have a temporary place in my rig. It’s still here after 3 years.

That said, I’’d still like to try a Modwright 90x, @elliottbnewcombjr located a great deal on one. I’m tempted to explore it further.

Did you discuss budget.

This versatile ModWright tube mm/mc was listed 4 days ago, plenty of gain (read the manual for facts). note: canadian dollars

https://www.canuckaudiomart.com/details/649985374-modwright-ph-90x-tube-phono-stage/images/4486346/

https://www.modwright.com/sources/ph-90-tube-phono-stage.php

.....................................................

Another versatile unit 

https://www.usaudiomart.com/details/649899087-vinnie-rossi-lio-w-avc-tube-stage-dac-phono-headphone-xlr-out/

@mdrone 

The problem is that the Leben has abnormally low gain. Most MM phono stages offer around 40db of gain.

I have had the Leben in my system and quite frankly it is quite vague - not worth the money in my view. Even a cheapy Soundsmith phono at around $1k was significantly better. 

My suggestion would be to get another phono stage or if you have the Leben, sell it and use the money for another phono.

If you're the patient type, keep a lookout for a used Herron VTPH-1MM. 44dB gain.

If you are considering the Marcof, I would really recommend the PPA2 over the PPA1. More load options,better parts.  Not sure but we may still have some new. I would have to get by Ed's, but I believe we a a couple 

+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.

What is the gain of the line stage that you are using? You should add that to the 28db gain of the phono stage!

You would need a head-amp with flexible loading and gain options. The Hagerman Piccolo is perfect for this, and not too expensive either. The only potential hang-up is it lacks capacitive loading options, though technically you can play with cables for this. 

Paradox phono-30 amplification is done via a pair of LSK170 JFET to providing 30dB gain and an external plug for loading your cartridge with any value resistor.

@mdrone  : Thank's. According the real time measurements made by J.Atkinson in theory the true gain is a little over 37db so you don't have to have a problem running  your cartridge other that maybe a higher than normal noise levels but the critical issue with your unit is that its RIAA accuracy is really poor and goes against the quality levels that your cartridge can shows:

https://www.stereophile.com/content/leben-rs-30eq-phono-preamplifier-measurements

R.

mdrone

I am using a Tavish Design Adagio with a Soundsmith Carmen II cartridge with an output voltage of  2.12mv ,  the MM ( MI ) gain is 44db . 

I was unsure if the gain was enough when I switched from a Grado with an output of 5mv since I am going thru a passive attenuator .  If you think that 44db is not enough I believe that Manley makes a phono pre that is adjustable up to 50db .

The phono stage I am looking at is the Leben RS - 30 EQ.

I’m thinking, set yourself up for future MC cartridge while you solve this problem

This seems to be a versatile unit, I’m sure there are others

Dear @mdrone  : Which phono stage do you own? , normally a MM phono stage comes with 40db gain.

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

the cartridge is a soundsmith Zephyr MK iii.

Output is 2.40 mV  Suggested Gain is 38-44.

The phono stage gain is only 28

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.

Has to have RIAA correction. 

You need a linear amp with added gain - a head amp. The Marcof PPA-1 will work! Battery-powered! I have one for use with low-output mc cartridges. Some Grado cartridges have 1 millivolt or less output. 

How low are we talking? What cartridge is it?