Koetsu Urushi + MC step up transformer

Nsgarch, You wrote, "spider, the values one uses to match a MC cart to a SUT have nothing to do with the load resistance you would use if connecting the cartridge to a phono preamp or headamp." Are you suggesting that my advice in my previous post was completely incorrect? If so, I'd like to know, because I hate to think I've misinformed spider (or anyone else). When he bought the Lundahls (presumably from K&K), I presume that they knew how he was going to use them and that therefore the ones he's got are already a reasonable match gain-wise for the Urushi playing into the CJ.

Re your last post, the consensus among us other users of the Urushi is that you would be best off with a load of ~100ohms. If you really want 47K ohms, then just off the top of my pointy head you will need to replace the 47K resistor at the input of the CJ with a very much larger one; the value would be 169 X 47K (given your reported 13:1 turns ratio), nearly 10 Megohms! You may as well try 10M. I don't recommend it but try it if you are convinced that the cartridge performed best into 47K ohms load. You are not alone in this belief; Allen Wright, a well-respected designer and manufacturer runs all his LOMCs into 47K. You need either to remove the stock 47K load resistor entirely and replace it with 10M or to place 10M in series with the 47K one.

Lew, probably what I should have said was that it takes different value resistors (across the transformer taps) to achieve the same load conditions for the cartridge as if it was simply driving a phono preamp. So your explanation of how to load the SUT seems perfectly logical to me, but then I've never tried to do it, so I have no credibility whatsoever ;-)
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I just did not want to be the dispenser of incorrect information. I've never used a SUT either, but I came close at one point and read some of the excellent white papers on the Jensen website at that time, to gain what little knowledge I have on the subject.

Spider, I hope it's clear in all this that the circuit should be as follows: cartridge to transformer to load resistor, so that the load resistance is on the other side of the transformer with respect to the cartridge and replaces the built-in load resistor in the preamp. To really make it simple, you could just leave the 47K resistor in place. With your transformers, that would result in a very acceptable load on the Urushi of about 200 ohms. (I'm too lazy to do the math.)

The maths works out as 47000/(13*13) = 278 ohms and I'll give that a try tonight.

Trying to replicate a 47K load through the transformer works out as 8M (47K*13*13) ohms as Lew points out. That will require modifying the pre-amp and seems quite a big change that is surely going to have an effect on the phono stage as a whole.

My thinking is that I probably don't need 47K load to get the sound I am used to and that I should take the SUT out of the equation and change the loading of the MM stage down until I find the lower bound. If that turned out to be only 3K for instance then that means I would only have to change the pre-amp to be 500K which seems more reasonable. Does that sound right?

I actually got the Lundahls from diyparadiso but Benny has been on holiday so I haven't been able to go through this with him. I'll also checkout the Jensen website and lookup Zobel networks.

Thanks for all the help so far.