VTL Tetrode/Triode

This also reminds me that we audiophiles are using a particular definition when it comes to the word "natural" - one where we are mostly talking about matters of texture and tonal and harmonic balances, and here the word applies best to triode. If we expand on that definition a bit to consider other aspects that could also be described as being more so, then I would say that tetrode has the more 'natural' spatial presentation, dynamics and articulation, and ability to resolve fine detail. But we normally use other words to denote realistic performance in these areas.

I'll also mention an analogy I've used before to sum up the different impressions I get from comparing the two modes: With triode, I often feel as if the performance is less 'electronically' rendered than with tetrode, but also that I'm listening to it at some remove, sort of as if I were in the next room - while in tetrode, the performance sounds slightly more like an 'electronic' artifice, but also as if it's a performance that I'm more in the direct presence of, in the same room with if you will. Or put another way, with triode I more feel like I'm hearing the real thing but also that I can't 'touch' it, and in tetrode I feel more like it's embodied right there in front of me, but that it's less quite like the original thing and more of a slightly 'off' clone. The choice is like looking through a window at your very own mother (triode) vs. exchanging a hug with her replicant (tetrode). I guess people buy even better amps (presumably - hopefully, for me - at a higher cost) so the two qualities can be combined to an even larger degree than these amps can manage strong glimpses of in the respective modes...

I think where we are seeing things different is in the presence part of our descriptions because we both agree that triode provides the most realistic rendering of the music.

For my system and ears the triode mode conveys much more detail and recorded room ambience, more direct palpable presence of the instruments than in tetrode (small group, preferably acoustic based music is forming the basis of this comment). Listening to Keb mo i feel that i could walk around him while listening to triode, not so defined in tetrode. For me tetrode tends to provide the wash of sound that you attribute to triode, though it tends to have more body/fullness, just not as pinned down and accurate..the slightly off clone that you describe.

Seeing that we agree on a number of our observations my guess is that the way our speakers (and rooms) deal with the different modes (and resulting drop in available power in triode) may play a significant part in our differences

What are your speakers/cables? To reiterate, I'm listening through Thiel 2.2's and either Satori or Au24 cable (though these impressions were formed only with the Satori, as I'm still evaluating the newer-to-me Audience cables).

Anyway, I'm not sure I can put a tag on which presentation is 'most realistic' so easily. I think it depends a lot on the recording and type of music. As I said above, in general I find tetrode more realistic in terms of qualities I would call 'physical'. But I think triode is more 'accurate' in its tonal and harmonic presentation. I've had some recent success in transforming the tetrode tonal balance more to my liking by both changing input tubes (the previous ones had become microphonic, and were brighter) and by placing tube dampers on them. However, I'm not quite done sorting this all out yet, because I've also gone from Svet 6550C's to EH KT-88's, and on top of that I haven't yet carefully evaluated again the tetrode/triode question with all the new tubes in place. Not to mention that I'm auditioning these speaker cables, which sound perhaps more transiently accurate but less warm than my reference, and I also just had a tweeter and crossover resistor replaced and that speaker is still breaking back in...it never ends :-)

Anyway, yes, my physical impressions are pretty much the opposite of what you describe in your second paragraph above, so apparently our 'clones' are 'slightly off' in different ways. Where you say triode gives you more detail, room ambience, palpability, walk-around transparency, and is more pinned-down in space, I feel tetrode does all those things better, with triode being the mode giving more body/fullness (if less extension and tautness). It's enough to make me wonder if our mode switches are wired-up the same way or if one's reversed! But I guess I envy anybody who's come to the comfortable conclusion that one mode is usually best for them...at some point here I'll revisit this question with the new tubes and post my findings.

I'm using Dunlavy Athenas, a VTL 5.5 pre, ARC CD-2 with harmonic tech pro silways between the CD and the pre and truth links from the pre to the amps (i needed 22 ft so budget had to fit in there somewhere).

I re-read your original post and noted where your switch had to be reinstalled...Putting it in 180 out could be the reason our interpretations are opposite.

As to the conclusion which is best it depends on the music, my mood and whether i have the ambition to get off the couch and monkey with the switch. If i had to live with only one it would be tetrode though...got to have that power when the application calls for it.

I was kidding about the switches being reversed - that's pretty unlikely with two monoblocks, and besides you can't mistake which mode has less power. Last night I did my first listening tests between the two modes with the KT-88's installed. I'm not ready yet to report with certainty, but preliminary results suggest that my impressions will be different with these tubes...