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

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.  

@flash56 

You have 2 easy options - 

If you purchase the Icon PS1 you would need to buy a SUT wth 1/10 step up ratio and plug it into the MM input. There are plenty of vintage units such as Denon AU320 or Denon AU340 that will do the job. Alternately bobs Devices are a company that build SUTs, get good reviews,  and they can advise you on the appropriate SUT to buy.

Second option is to buy the Soundsmith MCP2 phono. This has fantastic loading options and will match your cartridge. I have compared this phono, using a Soundsmith Paua, to some much more expensive phono stages, eg Lamm, Linn Uphorik and others and it is a very good phono.

Personally in your instance I would recommend you buy the Soundsmith MCP2, it's very good and will save you a lot of headaches. They also come up second hand  from time to time if you want to save some money.

It is unfair to blame Soundsmith for not knowing what is inside the Icon. It is clear from the comments by the Icon designer that they have chosen a fixed 100 ohm ;had for MC cartridges based on recommendations from Ortofon.

 

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.