Koetsu step up transformer - who knows about it?

I used a Koetsu step up transformer back in the 80's w/ my Koetsu Black. Then I went all-digital until about 6 months ago, when I re-habbed my Linn and bought a new Koetsu Black. And not long ago, I came across my old Koetsu transformer, unused for some 17 years.

I hooked it up last night (using an EAR 834P phono pre, in MM setting). The sound was interesting, and sort of good. I played a couple of Lps that previously sounded kind of edgy to me (an EMI Barbirolli Vaughan Williams for one). They now sounded more full, and almost dark. In fact, as I was first listening to it, it sounded so dark I thought there was something wrong with it, and tried some different Lps. I think in theory it shouldn't need any warm up, but it seemed to sound better after it had been in use for a bit. (Sure, it could be pure psychology...)

I saw a similar Koetsu transformer listed on Audiogon a few months ago for $2K. Seemed kind of high to me, but maybe I don't realize what I have. Maybe systems sounded a lot different 20 years ago.

So who knows about these, and who can tell me what they're supposed to sound like, and if what I seem to be hearing is what is supposed to be there, or if something like this would go bad after this many years...is there any upkeep that should be performed, etc.?

Many thanks

theres not much information to find about these exotica. The price of the actual unit is >3000,- $ or Euro. I have one of the very very rare, earliest model (with some more japanes letters on front the the actual model (it says Musashino Sound Institute in Japanese)). The older models use Alnico instead of permalloy I've hear. The newer ones also don't have custom wound transformers as the older ones, instead they have OEM ones from some manufacturer. There should be something like 3 different models. But this is just what I've heard.

Some people say theyre no very good transformers and therefore overprized. BUT I think at least the older ones are very fine and well balanced step up transformers. I use several others like Audio Note/Kondo An-S6c, Auditorium 23 T1, Jensen 346, Denon Au-S1, Kiseki MCT2...compared to the best I know the Koetsu step up I have is comparable in musical satisfaction...if not the most analytical or neutral. here we are talking about "tone" and the Koetsu step up fits wonderful synergetically with a Rosewood for instance.

I heard my Koetsu step up with a Rosewood vs. my Audio Note S6 with Audio Note Io Gold in a friends system. To be true I liked the Koetsu combination more. But both played on a very high level.

i would keep the step up and would get a actual Koetsu since these will yield high musical satisfaction.
I agree with the statement that no mc tranformers sound worth a damn. I personally wouldn't give you $.02 for any of them. If you want to read one of the best articles I think was ever written on the sound of step-up devices, get the copy of TAS where David Wilson wrote the definitive article (this was before he acheived fame and fortune as the Wilson Audio company). I agree with David Wilson 100% Transformers rob the life out of the music. They dumb it down. If you want to use a low output mc cartridge and you want the sound to resemble live music, you need an active device. I have a Counterpoint SA-2 pre-preamp which is all tubes including the rectification and voltage regulation. If people knew how good these sounded, they would be selling for $10K in this wacky hobby. As it is, they rarely come up for sale and they are a steal at whatever price is being asked.
Xronx - Many thanks for your thoughtful response. In fact, my Koetsu transformer is apparently similar to yours--there are Asian (I assume Japanese) characters on the front (two of them, one above the other). And, of course, it is from that vintage.

The more I listen to it, the more I respect and enjoy it. I have been using a Rhea phono stage, about which I have mixed feelings, and I just sent it in to Steve Huntley at Great Northern Sound to modify...which is in part why I happened to be looking around at my other gear and decided to try out the rediscovered Koetsu transformer. And, I should be clear (in response to your last comment)--I am using a Koetsu Black cartridge. Perhaps at some later point I will move up to a Rosewood. But the Black is very pleasant.

With respect to Mr. Wilson's reported comments about transformers "dumbing down" the music, I just don't what to say. What I'm hearing is definitely music, and it's rather sweet and alive. But everyone's ears focus on different things. And, I don't care for the man's speakers (based on the few times I've heard them). So I guess we're looking for something different in the reproduction of recorded sound.
I would say trust your own ears, if you like the Koetsu step up..keep it, if not sell it :)

I was a solid state guy for years and had some phonostages like Gryphon Orestes, ASR Basis Exclusive, Audio Research PH5...the point when I started to listen to music instead of Hifi was when I discovered my Paragon 12a tube preamp and transformers...

My experience is totally different to the things Mepearson said. I dont know if he has any experience with very very good step up units like Audio Note, Kondo etc..

In direct comparison no active phonostage I tried against the Paragon Step up combination could made so much dynamic lively and almost touchable music in my listening room. Not even the highly regarded Gryphon Orestes (>7000$). With my Audio Note step up and the Paragon I had not to sacrefice anything in precision, frequency extension to active phono stages. Sometimes I think transformers have a bad reputation to some people before they ever had the chance to hear a top transformer under good conditions.

And personally I cant trust what Mr. Wilson says...I had a Watt Puppy 5.1 and I have to say that this was dead, sterile and boring sounding compared to for instance my Cabasse 500. So his taste how music sound is maybe something wich doesnt get along with me...

I just can propose in general to try to listen less to "more bass, more resolution..." whatever and judge a component more after if music is touching more or less via the specific unit.
Does anyone have the Koetsu step up transformer for sell I like to buy it, thanks!
Xronx is giving good advice.

Oddly enough, I too compared a Rosewood cartridge through a Koetsu SUT (unknown vintage) and an Audio Note AN-8. The AN was much more revealing, and I would have to say somewhat better - but the cost!

What I eventually did was to build my own SUT box with Sowter 8055's, Vishay VAR loading resistors, and ETI RCA's - total cost, much less than $1000, and nearly as good as the AN-8; not quite as revealing, a little softer, but very musical.

All tests in my own system, using ESL's.