Does anyone have experience matching an Icon PS1 MKII with a Soundsmith Zephyr MIMC Star?

Dover, I guess you haven’t read the thread.

Dover, Apparently the Icon PS1 has a bulit in SUT about which there is much confusion, as you know. We don’t know how they achieve a 100 ohm input R with the built-in SUT, which is said by them to be 1:10. One way to achieve a 100R input impedance with a 1:10 SUT would be to use a 10K resistance on the phono input side instead of the standard 47K. If that is the case, then it would be futile to use an outboard 1:10 SUT (bypassing the internal SUT) in hopes of achieving a 470 ohm net impedance for the Soundsmith MI cartridge. You'd still end up with the cartridge trying to drive 100R. This is assuming that both the MM and the MC inputs feed the same phono circuit. Easiest thing to do is not to buy the Icon.

Any unadulterated SUT with a turns ratio of 1:10 (i.e., a voltage gain of 10X) will show the cartridge a 470 ohm load if connected to a standard MM phono stage with an input resistance of 47K ohms, which is the industry standard and has been for probably 80 years.  These are laws of physics. So price is not an issue; a cheap SUT will yield the desired impedance. To achieve a higher impedance, you must use a SUT with a turns ratio of less than 1:10.  Then do the math as described in my post above.  But 1:10 seems perfect for your needs.

It actually would be a simple matter to open up the chassis of the Icon and find out what is really going on, then fix it so you end up with the cartridge seeing 470 ohms, but that is assuming that their other information stating the turns ratio is 1:10 is correct.  We don't even know that for sure.  So yes, buy something else.

By the way, I don't understand why you would indict Soundsmith.  They can only reiterate what is in their package insert, that their cartridge wants to see at least 470 ohms.  There is no reason to expect PL to be an expert on the Icon.

You would not achieve a 100R load by putting a 100R resistor across the secondary. God forbid! That would result in the cartridge seeing a 1 ohm load across a 1:10 SUT. But if they inserted a 10K ohm resistor, THAT would result in a net 100 ohm load seen by the cartridge. But it seems they have denied doing that and claim they use a standard 47K ohm resistor at the phono inputs. Which would indeed result in the desired 470 ohm load. (Cartridge load is equal to the value of the resistor on the secondaries divided by the square of the turns ratio; 10-squared = 100. 47,000 divided by 100 = 470.) They cannot have it both ways. So some info is missing OR in fact you have no problem.

I think you mean 470 ohms, not 470,000 ohms.  But you would not want to load your Sussuro at only 100 ohms.

I have to suspect Icon installs a resistor across the secondary of the SUT, thereby reducing the load seen by the cartridge to 100 ohms, instead of the expected 470 ohms. Either that or the base load resistor at the MC inputs is 10K ohms instead of the standard 47K ohms. Either way, the problem is easily remedied. But I agree that the seller gave bad advice to ignore the issue entirely.