the tough question: Which preamplifier? and why

Larryi hit the nail on the head. This has certainly been my experience time and again. My most recent example is a CJ pv10 and premier 14. While the 14 was under repair I put my spare pv10 in and the result was an incredible improvement. They were driving Mcintosh 501's which have a low input impedence - the pv10's output imp is around 800 while I believe the 14 is around 200, I'm guessing that's the reason? The synergy is clearly better in every area.

That's what I thought lower output impedance for lower input but this one shocked me. I'm using MIT 350 ref 1 meter which has a higher capacitance I believe.

Now that the slap fight is over, I stand corrected the pv10 is 800 ohms and the Mac is 10Kohms so the 10 to 1 ratio applies...

Tvad, it does sound warmer, richer, cleaner highs, better seperation, better tonality all around. This was not the case when these preamps were connected to a Classe amp which has an input impedance of 47K.

Tvad, I'm telling you it's bizzare, better bass definition and clearer, cleaner highs...what gives?

I've been looking for this and the texture I use to have and it was right under my nose. I don't think the premier 14 has it compared to the pv10. I've tried several cable combinations trying to get it back, put the pv10 in and whoa! there it is!