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


I own Soundsmith Zephyr MIMC Star LO cartridge. I am looking to purchase an Icon PS1 MKII phono pre. The PS1 uses a passive 10:1 SUT with a fixed 100 ohm impedance for the MC input. The Soundsmith Zephyr MIMC Star cartridge requires a minimum 470 ohm load. Music Direct is telling me that I should be fine. But I would be interested in hearing from someone who has experience with this actual combination. Thanks.

flash56

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.

Icon appears to be very elusive with giving any kind of definitive answer.  In this review of their PS3 Icon Audio PS1 Mk. II All Valve Phono Stage — Audiophilia Icon expresses their view of step-up transformers stating So, that is why IMHO (and Ortofon + others) a good quality 10x step-up transformer is all you need. (at about 100 ohms).

I am not sure what Soundsmith can add.  They will only know what you know, and be as confused unless they know of a customer who has used an Icon with one of their low output cartridges.  

Here is a review of the Paua and the equipment list is an Icon PS3 which is the reference I found to an Icon and low output Soundsmith.  Just in case, do you have the option to return the Icon, that would be the safest option.

Icon has yet to respond to my question as to how they calculate a 100Ω load. I ask them if they were using a RC across one or both ends. It seems as if they are ignoring the question.

After sending Soundsmith the specs of the PS1 MKII. And describing what my concerns were. Explaining to them, that I felt that I was out of my depth concerning SUTs and asking for any advice that they could give me concerning the issues. After waiting two days for a response. The response that I received was, "Peter says that the Zephyr needs a ≥ 470Ω load." WELL, NO S###!!! I may be unfamiliar with SUTs. But I can read basic specs. Thank you.

Quite frankly, I am disgusted with both companies at this point. I spent $2,000 on a  SS cartridge and that is the best advice that SS can offer?

And as far as Icon is concerned. Give me a break!. You haven't discovered cold fusion, or room temperature super conductors. It is a SUT for god's sake! Why all of the covert BS?

I have another question for this forum that is related to this thread. Can anyone recommend  a company that makes a SUT with a reflected load of 470 ohms or greater, at a reasonable price? I can't seem to find one. I would welcome any suggestions that might steer me in the right direction. I have, once again, ask Soundsmith for suggestions. I will wait to see if Peter has the time to give me a useable response this time. Until then, I must rely on this forum for information.

BTW, I have yet to purchase the Icon PS1 MKII. And I seriously doubt, at this point, that I will. And, as much as I like the Zephyr MIMC. I don't like to be boxed in with no options. I am rethinking my entire approach at this point.

Thanks again for your advice. It is highly appreciated.

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.

If all you are looking for a SUT, then suggest MovingCoil (erhard-audio.com).  He took over for K&K when Kevin got out of the business.  Erhard builds with Lundahl SUTs and there are a number of different versions (kits can be fully built for a nominal charge) at various price points with most having 2 different ratios such as 5 & 10:1 and 8 & 16:1.  Lundahl does not offer a 10 & 20:1.  The 8:1 should yield about 735-ohms which would be good for the Soundsmith, while 16:1 would offer about 184-ohms which would offer you the opportunity to use a moving coil cartridge.  You can contact Erkhart and see what they recommend for you price point.  Then you just need to mate the SUT with a MM phono-preamp noting that you want to keep the cable between the SUT and the phono-amp short.  Also, the MM phono preamp would need enough gain.  I have no specific recommendation for a MM phono preamp but depending on whether you want SS or tubes, there will many recommendations.  But understand that using an external SUT is just one way of doing this.