Higher Impedance MC Carts on Transimpedance Stages?

The inductance of an LOMC is trivial, in the sense that it’s very low, on the order of 1000 times lower than MI which is already much lower than MM. Your acquaintance is probably happy because it works and he has yet to try an LOMC with truly low internal resistance. I feel that I must be misinterpreting Hagtech’d equation .

There is no real contribution from phonostage, since it appears as a dead short, we are talking transimpedance, right?

Nevertheless, first order bandwidth rolloff is from L/R ratio of cart (and tonearm wire). Think current, not voltage.

I know it may feel counter-intuitive, but what is happening here is a sacrifice between output amplitude (maximum current) and bandwidth. 

Similarly, the gain you will need from transimpedance stage (assuming it's like an SUT into MM phono) is given by:

G = 5R / V;

where R is cartridge resistance (plus tonearm wire) and V is cartridge output in mV. For example, an 0.3mV cartridge with 8 ohms gives G = 133 ohms.

Yes, gain for a transimpedance stage is given in ohms... 

@hagtech +1

Transimpedance works nicely if you have a nice low output. Not so well as the impedance of the cartridge goes up.

In a transimpedance circuit, the cartridge replaces the input resistor of an opamp. The gain of an opamp circuit is the ratio between the input resistor and the feedback resistor. Since the feedback resistor is fixed, this means that the lower the impedance of the cartridge, the more gain the circuit will have (and also greater distortion since there is a trade-off between the two).

The loading is less than ideal. The cartridge has a certain compliance which interacts with the mass of the cartridge and tonearm, resulting in a mechanical resonance. This resonance should fall between 7 and 12 Hz for best tracking. When you load the cartridge with a low impedance, the result is the cantilever becomes harder to move (so has less compliance). This results in a very measurable loss of ability to trace higher frequencies. So at best the cartridge choice has to match the transimpedance circuit so this doesn't happen in the audio range.

As Deep Thought once said, 'Tricky'.