Hi everyone, So. I finalized my second stereo system after having restored two Eico HF-22 monoblocks, and having acquired a C22 (1960-s version) in rebuilt condition (recapped+power) plus SA-14S1 SACD player (used but fairly new - I picked it because I had one I bought new and I liked it, and the price was good) I put it to the test. The speakers I have are a pair of Klipsch Cornwalls, the ones with vertically oriented horns. The C22 which is the item in question here had originally JJ 12AX7 in it mixed with Marshall ones. The Marshalls tested a bit on the lower side (still good, but one of them borderline) and they were, I think, in V5 and V6 places. Well. I listened to some things I have in my phonotheque - - Nazareth (Malice in the Wonderland) - QUEEN (II, NITO) - Vivaldy Stravaganza (Rachel Podger) - Tom Petty (the best of, mostly using the "Free Fallin'"). - Lynyrd Skynyrd (Sweet Home Alabama). The system sounded great the way it was. However knowing a couple of tubes deserved retirement I ordered the following setup from Jim McShane (I only say that to anticipate the questions about what the source of the tubes was - I think with Jim it is as good as it gets); my choices were pretty much the result of consulting him: - Two Sovteks for the Phono input (that I was not using in the audition as I am not playing the phono at this point, so I used the placeholders - the tubes that are not necessarily good but will provide the needed filament interconnect) - Four Genalex Gold Lion for the V3-V6 position - Two Tung Sols ECC803S to try in V3&V6 positions (described as "more energetic") - Two good original used Mullards ECC83, that Jim had for sale. So the first arrangement was all (except the noted V1&V2 phono tubes) Genalex. Then I tried the Tung Sols, and then - Mullards, getting back to all Genalex. What can I say. Before you guys start bashing me, I have to say that as a child I was diagnosed with "Golden ear" condition which, I believe, still persists (I recently started learning playing classical guitar and my teacher is quite amazed with what I have, though my playing...well....sucks but this is the hands, not the ears). After putting the Genalexes in, I noticed.....no perceived change. I did sound great before, it still sounded great, but when I went back and forth, those details that I noticed did not change with the tubes. Then I put the Tung Sols in V3 and V6. I tried to listen to it after warm-up, tried to see the "more energetic" changes....I failed to discern anything different. And then there were the Mullards. With very much the same results. I spent quite a bit on the extra tubes. I do not regret it, it is good to have a supply of good tubes if one owns tube equipment. But......here's what I want to ask: Is there any setup you guys use when doing that type of comparative listening? It is not like I intend to go the whole hog and buy two C22 amps and a switch. (I mean, I do have a second one, but it is a re-issue so not quite exactly the same). Obviously comparing sound after you played one set, then turn it off, swap the tubes, turn in on, wait 'till they are warmed up, is not ideal at all - you will forget the sound of the first set by that time. I even think maybe what would help is building a small chassis with several tube panels and extention cables, and a switch that would keep the tubes hot and switch only the non-filament electrodes (has to be thought out well, as that could result in popping/transients/etc), so different sets could be plugged and evaluated without long wait, but.....if there were substantial differences, wouldn't I noticed at least something? I'd like to hear from folks with experience of doing this kinds of things. Best, Mike.