What is the Sound of Impedence Mismatch?

Yes Bob I am familiar with LCR effects in cables. What's your point? I was answering the question about preamp amp interaction without considering cables. Poulkirk brings up the professional 600ohm standard which while correct is likely not answering the question which is probably possed from a RCA connection perspective. I was addressing the loading issue, not a potential frequency rolloff due to inductance effects. You might want to explain the issue of frequency rolloff to Drubin and how the R in the LCR circuit is partially the output impedence of the preamp since you are so keen on it.

Thanks for all the input everybody. It's the damndest thing, but the brightness has gone away. I loaned the First Sound to a friend for a few days, and ever since its return it has not sounded bright at all with the Pass amp.

This hobby can be so maddening sometimes!

--dan

And now, the First Sound sounds too dull and soft with the Pass. These days I am using a 4M run of interconnect, which could be a factor. Or I could be losing my mind.

Dan

Nine months later, I still wrestle with these same issues. The First Sound sometimes sounds too dull (or soft) and sometimes it's plenty alive. Honestly, I think it is variability in my hearing that does this. How can it be that one week I'm ready to sell all my tube gear and the next I want to dump the solid state? That's why I still have both.

dan

May I suggest you look up the thread: How to match ohms with amps & preamps