What's a Triode configuration?

Your last paragraph is probably the most important factor. I'm going thru it right now. I have a very nice preamp that unfortunely is a mismatch with my amp. Even after lowering the amps input impedance the pre has too much output impedance and overloads the amp causing a distortion.

Kora makes a nice tubed pre-amp, called the Equinoxe, I believe. I had very good success with its predecessor, the Triode. I ran the Triode with both the (SS) Plinius SA-100 and the (SE) Melos MAT-185, both with good success. There is a Triode for sale on the Audiogon right now for $400, I think.

Of course as Jeffreybehr points out all low level signal amplification is done with triodes, often the ubiqutous 12AX7, and its clones. The alternative to a triode is the pentode, which is used in power amps that have transformers. The extra grid in the tube is used to apply feedback from the transformer secondary winding so as to correct frequency response deficiencies of the transformer, and, as a secondary purpose, to reduce distortion.

IMHO your shopping list should not be constrained by arbitrary factors like the type of tube. You might not like the sound of triodes.

Audiogabby - sounds like you have a gain mismatch as opposed to an impedance mismatch. An impedance mismatch will usually result in prematurely rolled-off bass and treble. You are seemingly describing overloading the input stage of your amp. You need to pad down the output of your preamp. The easiest way is to get an outboard attenuator of some kind. The best way though is to see if the manufacturer of your preamp is able to lower the gain structure and if so send it in for updating.

Judy426 Is it actually a deficency with the AR or just a compatabilty mismatch between componets and ICs? I have been pretty fortunate with my matching and get very nice sound but I have been careful as to what I had and how I've changed. Also I have a great counsouler to toss opinions off of too. Right now I was looking as to how I tell differences between a pentode design and/or Triode, are all the AR Pre Amps/line stages Triode or what design would they be? Wanting AR is my personal choice I have always loved them and they were always out of reach for me, it's my personal dream. Now if Sonic Frontiers or another Pre was a better choice I am open to it I'm not being closed minded by any means, when I make a consideration for a seperate amp it will be a Classe though, becuse that was the reference for my speakers and I am hearing the joy of that matching and from the power cord changes I've made, so there I'm being unflexable at this time but, a Pre Amp to match might not be the AR as I would like and I'll have to ask at the time of that impemding change still again. We all have dreams and at this time AR is my first choices.