I love my SUT's and have a small collection of 6, but certain cartridges pose a challenging electrical match for a SUT when your MM stage is fixed at 47K loading.
One example is the Benz Ruby / Gullwing / LPS. These have an output of only 0.34 mV to a (relatively quite high) coil impedance of 38 ohms. And your DV Karat is spec'd very close to that: 0.3mV at 32 ohms. An ideal SUT ratio for 0.3mV is the range of 15x - 20x step-up. Let's take 20x gain - into 47K, which makes a reflected load of 118 ohms back to your cartridge. Most "rules of thumb" will say you want at least 10x load-to-coil ratio. In this case, 118 ohms / 32 ohms is only a ratio of 3.7x. You're going to be throwing away 2.0dB of cartridge signal in this scenario from Ohm's Law (and hence the noise floor creeps in that much more), and also probably introduce other sonic aberrations that the cartridge designer didn't intend.
I've successfully used as low as 6x load-to-coil ratio, but it's still not optimal and some cartridges will object to that more than others (Koetsus seem relatively well behaved as low as 6x). Below 5x is really asking for bad sound. BTW I've also tied the Benz LPS into a SUT and it just will be nowhere near its potential at 47K loading, no matter the SUT ratio (I have several to try).
Now if you had phono stage that could run higher than 47K load in MM mode, then you could "fix" this problem. A load of 100K with a 20x SUT reflects back 375 ohms. 375 / 32 = 11.7x. That's OK! The Rogue Ares Magnum is one example of a phono stage that allows loading well above 47K in MM mode, but unfortunately this feature isn't nearly as common as I'd like it to be.
So in short, I'm normally one who encourages SUT experimentation (even after college), but not with certain cartridges without the right MM loading options. In your case, I'd pass on the SUT.
One example is the Benz Ruby / Gullwing / LPS. These have an output of only 0.34 mV to a (relatively quite high) coil impedance of 38 ohms. And your DV Karat is spec'd very close to that: 0.3mV at 32 ohms. An ideal SUT ratio for 0.3mV is the range of 15x - 20x step-up. Let's take 20x gain - into 47K, which makes a reflected load of 118 ohms back to your cartridge. Most "rules of thumb" will say you want at least 10x load-to-coil ratio. In this case, 118 ohms / 32 ohms is only a ratio of 3.7x. You're going to be throwing away 2.0dB of cartridge signal in this scenario from Ohm's Law (and hence the noise floor creeps in that much more), and also probably introduce other sonic aberrations that the cartridge designer didn't intend.
I've successfully used as low as 6x load-to-coil ratio, but it's still not optimal and some cartridges will object to that more than others (Koetsus seem relatively well behaved as low as 6x). Below 5x is really asking for bad sound. BTW I've also tied the Benz LPS into a SUT and it just will be nowhere near its potential at 47K loading, no matter the SUT ratio (I have several to try).
Now if you had phono stage that could run higher than 47K load in MM mode, then you could "fix" this problem. A load of 100K with a 20x SUT reflects back 375 ohms. 375 / 32 = 11.7x. That's OK! The Rogue Ares Magnum is one example of a phono stage that allows loading well above 47K in MM mode, but unfortunately this feature isn't nearly as common as I'd like it to be.
So in short, I'm normally one who encourages SUT experimentation (even after college), but not with certain cartridges without the right MM loading options. In your case, I'd pass on the SUT.
