PMG Phono Question

Audio Components
1

I just watched Paul’s video discussing the PMG Phono preamp and expected availability.

I have some questions about the transimpedance application. I have a moving magnet phono stage with a transimpedance step-up amplifier. The step-up unit has a single dial that adjusts resistive loading and gain at the same time. As gain increases, resistance decreases. For a lot of cartridges, when the recommended resistance is set, there is enough gain. Not so in my case. I use a Soundsmith low output Zepher MIMC Star. This cartridge needs a resistive loading between 470 – 1,000 Ohms and a gain of 58 – 64dB. My transimpedance step-up amp only goes up to 300 Ohms at which point it has 9dB of gain. I don’t use this phono/step-up stage for the Zephyr Star. I use my Stellar phono preamp with custom loading set at 750 Ohms and Low Gain.

My question is, since the PMG phono preamp uses transimpedance, will it work with Soundsmith’s low output cartridges.

2

I have the same question since I have the same moving Soundsmith moving iron cartridge.

3

My take from Paul’s comments is that transimpendance is only on the MC input. And I am surmising that those of us fully satisfied with our MM cartridge (Ortofon 2MR LVB Black on a Rega P8) won’t get a big SQ boost from Stellar → PMG. Not sure I want to re-explore the realm of MC, in part because I now discount most reviews as there is no way to know if the cartridge was properly set up. And if you spend a spare Saturday exploring a sub topic, say, anti skate, you might come away wondering if anyone actually knows the optimal set up parameters, even presuming the cartridge itself is “perfect”. Willing to bet an outside “expert” mounted the Lyra on PS Adios VPI turntable.

4

Transimpedance (in the sense mentioned by Paul) is used only with MCs having very low internal resistance - ideally much less than 10 Ohms.

5

As seen on the back panel of the PMG Signature Phono Preamp it has voltage inputs for MM/MC as well as transimpedance inputs for MC. So for MC cartridges it will provide you with the option to use conventional voltage gain or transimpedance (current) gain circuitry. As some have stated transimpedance gain works best with low output impedance MC carts so you’re given a choice.

6

Yes but a Soundsmith Zephyr MIMD Star is a low output moving iron cartridge. On the Stellar phono preamp I run it at 800 Ohms and medium gain.

7

I’d suggest contacting PS Audio’s customer support to ask about compatibility with your cartridge and desired settings.

8

Won’t work (or won’t work well). I’m pretty sure the lowest internal resistance MI cart made at SS comes in at about 10 Ohms. Can’t (or typically won’t) get the best out of such a cart with a transimpedance stage.

9

So it will come down to what loading/gain options are available on the MM/MC inputs.

10

I noticed Paul mentioned no Optical Phono input. The Transimpedance current drive idea sounds cool. I’m sure that Darren’s Design and Bob’s implementation will be different from the Sutherland stuff.