Nothing blows up. The mating would be inefficient as the internal impedance of the cartridge exceeds the input impedance of the BMC, which we think is around 2-3 ohms. Thus some of the signal voltage derived in the Kiseki would be lost to ground. But also, the Kiseki probably produces very little signal current; you can estimate that by dividing its output voltage by it internal impedance. I don't know the output of a Kiseki but for example if it is 0.4mV then its signal current is around 0.4mV/40 ohms = ~10 micro-amperes. For comparison, even my Ortofon MC2000 which produces only .05mV of signal voltage makes 25 micro-amperes of signal current because its internal impedance is only 2 ohms. Nevertheless, one might take advantage of the BMC's adjustable gain (0, +7, +11, or +14db) and set the gain high using the internal jumpers. My prediction is it won't be satisfying but worth trying.

Higher Impedance MC Carts on Transimpedance Stages?

Can anyone explain what happens if one pairs a transimpedance / current injection phono stage with a moving coil cartridge whose impedance may be higher than optimal? What would the result be?

This question arose from someone who wanted my thoughts on the BMC MCCI Signature ULN phono stage that I use as my reference, but that individual is using a Kiseki Blue which is spec’d to have an internal impedance of 40 Ohm, which I’ve found is higher than typical MC cartridges.

@lewm and @rauliruegas, you guys likely can answer this easily, but of course open to anyone else that can explain.

Thanks!

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- 13 posts total

- 13 posts total