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

Another update.

Icon finally responded today. I said that I would post the response. So here it is. Just to put things in prospective, I am going to post my question also. David at Icon had said that it was strange that there was no mention of SUTs on the SS site. And speculated that the cartridges were designed for MC head-amps only. Antinn had been kind enough to post the link.

Question:

Hi David,

Thanks Antinn! I will definitely check into it. It would be nice to have it refurbished. It is a good preamp. Much like the design of the Manley Chinook but without the loading resistors and capacitors being installed into dip switches. There are posts in which to solder the needed resistive or capacitance loads. It uses the same 6922s for the gain stage. It differs from the Chinook by using12AT7As for the output stage.

I want to apologize again to Soundsmith. I was just frustrated and had hoped for some guidance. I should not have taken my frustration out on them. It is really Icon that deserved all of my frustration, not Soundsmith.

In fact, it was Peter Ledermann who told me, in the first place, that if I could get a schematic from Icon that he would be happy to look at it and tell me if the circuit   allowed for a simple modification. That is what started my whole quest with Icon. Only to be told half-truths. Saying that there was no schematic simply because all that the MC circuit consisted of was a simple 1:10 transformer. They knew that I was looking to alter it to fit my needs. And when I had managed to educate myself enough, thanks to this forum and other publications, to question them on the 100Ω impedance. Simply because the math didn't play out, if it was, indeed, only a simple 1:10 transformer. And requested for a second time to be given a schematic of the MC section. That request has resulted in silence. Not even giving me a response at all. Or so it would seem. Quite possibly they are working on a response. And I will receive one eventually. If I do. I will let you know what that response is.

I feel good that Peter is doing the SUT. He will make sure that it is done correctly. As he states. Not all 1:10 transformers are necessarily a good match. The impedance of the transformer windings come into play. That can differ by the construction. How tightly together they are wound. The core. All of which can make a difference in the impedance. He designed the cartridge. And I have absolute confidence that the SUT will do the job correctly.

Thanks, one more time, for everyone's feedback and advice.

@flash56,

Parts Connection Parts Connexion services Sonic Frontiers components and does improvement mods on some.  I am quite sure they could refresh your SFP-1.  

An update.

I take back what I said about Soundsmith. Peter Lebermann quickly responded. He said that he would supply me with a stand alone SUT for the Zephyr MIMC for a very reasonable price of $500. I have taken him up on his offer. So that problem is solved.

I am currently using an old Sonic Frontiers SFP-1. Which is a tube phono pre that uses a FET MC step-up pre. I am going to use the SUT with it through the MM inputs. And see what a SUT sounds like. Maybe I will like it, and maybe I won't. But I am intrigued enough that I want to find out. The Sonic Frontiers is getting old. The company no longer exists. And I have yet to be able to find a schematic for it. If anyone should know where I might find one. Please pass that information along, If you would be so kind.

As far as Icon Audio is concerned. Now that I will have a stand-alone SUT that matches the Zephyr. I would consider purchasing the Icon PS2 MM phono pre. But the fact that they have not yet bothered to reply to my very valid questions concerning the PS1 MKII causes me hesitation about doing business with them.

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

@flash56 

Both the suggestions by @tablejockey are good options.

Manley Chinook & Zesto Andros. I've listened to the Andros for a couple of years with a variety of cartridges - it's very good. musical and underrated in my opinion.

@lewm 

You are muddying the waters again.

The Icon PS1 MM input is 47k and an external SUT 1/10 will load the cartridge correctly.

All you are doing is confusing the person who started the thread with your hypothetical postulation.

Using the SS MIMC with a tube phono doesn’t need to be so involved.

The OP can get one of these for LE$$ and either choice is good

https://www.audiogon.com/listings/tube-zesto-audio-leto-1-5-preamp-2017-06-21-preamplifiers

https://www.audiogon.com/listings/lisbbb6a-manley-chinook-limited-edition-phono

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.

@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.

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.  

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.

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.

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.

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.

Thank you Antin for the Soundsmith link. I could not find it. That is reasurring.

I have been in contact with Icon. They made the comment that transformers are largely self adjusting.  I also asked them for a schematic of the MC input. They are telling me that there is no schematic since it is merely a 1:10 ratio passive transformer with a required output load of 47KΩ. And that I should follow Soundsmith's advice.

I have contacted Soundsmith, and supplied them with the PS1 MKII Specs. I  am waiting for a reply.

I am also confused about the 100 Ωs. If Icon is using a 100 Ω resistor across the secondary. Then they should have notified me of that, or sent, what amounts to a schematic showing the 100 Ω resistor across the secondary. Which could easily be removed from the circuit.

My calculations were exactly the same as the Soundsmith link.. The source should see a 470 Ω load. Which is perfect. If the Sussuro is seeing 470 Ω. Then that is what I should expect with the Zephyr Star.

I am anxiously waiting for Soundsmith to weigh in on this. I will let you know what they say. But from what is stated in the link. It seems to imply that a 1:10 SUT should do the job of delivering a 470Ω load.

I am also going to supply Icon with that link. And inquire how the 100 Ω load is being calculated.

Since I am unfamiliar with SUTs. This has proven to be an education for me.

Thanks to all for your responses.

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 a low output Soundsmith cartridge (Sussurro MkII ES) and it sounds perfect through a 1:10 SUT that shows it a 470KΩ load.

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.

Soundsmith specially states a 10:1 ratio SUT is perfect for their low-output MI such as the Star - Transformer use with Soundsmith MI/Fixed coil designs | Soundsmith (sound-smith.com).  A 10:1 SUT should yield 470-ohms load to the cartridge.

However, the Icon manual icon Audio clearly states 100-ohms which does not make sense since their literature on the separate SUT -icon Audio states:   The impedance of a transformer varies according to its load, so in this sense they are self adjusting.

Contact Icon Contact Us | Icon Audio and a get a specific answer.  Does the 10:1 SUT actually load the cartridge at 470-ohms.  Tell them you are using a Soundsmith low output MI that needs 470-ohms.  

Music Direct are misinforming you.

Loading the Soundsmith cartridge below the recommended 470ohms load will result in awful sound.

You need to find another phono.