Koetsu Step-up Transformers

Anyone out there have any experience with the Koetsu step-up transformer?
RC, I owned one in 1985 to run the Koetsu ONYX sapphire I had, going into an ARC Mag phono input. While I assumed it would be the step up of choice, the Cotter, beat it in the Mk IIL version. I later purchased a preamp with enough gain, and that beat all of the boxes I had on hand (including the highly regarded Klyne and ARC MCP-33. Hope this helps.....Frank
Koetsu is good, but try Vendetta SCP2-D (I go from Red Signature to ARC SP10-II input!)the best even made.
Good luck!
Thank you both for your input. Actually, my preamp has considerable gain (Jadis JP80, which replaced a Vendetta/Jadis JPL combo years ago), but the Koetsu cartridge I recently purchased is low enough output that it forces me to turn up the volume pots to where tube noise and a persistent hum I still haven't gotten rid of become intrusive (this problem was not noticable with the higher output Ruby 2 cartridge it replaced). I once used an Expressive Technologies step-up with the JP80 for a Transfiguration cartridge with excellent results, but sold that years ago when the Transfig. gave up the ghost. Silly me! I have a chance to pick up a recently manufactured Koetsu step-up for a decent price, with a home trial, and do a favor for a friend at the same time, so ultimately I can decide with my ears, but I was curious about others' experiences because I had not realized Koetsu made them.
The Koetsu is very under-rated. I owned many step ups, except the Expressive Technology. I have Cotter P and L. To use with Koetsu, the best sound is obviously with Koetsu step-up, followed by P and L. I just don't find L better than the P. The sound of L was too under-damped for me.

If you find the Koetsu lacking it is because there're some tricks into getting it to work and sound well. Pay particular attention to the grouding, as unlike Cotter, the Koetsu was constructed with wood case, not metal.