VTL Tetrode/Triode

horsepower wars in sound reproduction, man how reality changes. I remember in the early 80's when i played in a loud rock band (we're talking marshall half stacks running 3/4 by the end of the night)and all we had driving the vocal mains was a lowly crown dc 300 that need a fan blowing over pitchers of ice to keep it cool enough to run. The last band i was in was a pretty quiet blues band and we used almost six thousand watts a side for the mains. My home system is the same deal, i'd love a mb750 for my 14 by 22 room and i'd probably play it quiter than my high school system of klipsh cornwalls fueled by a crown d 150. Headroom is a good thing.

first, as to the potential for switching with no signal, i wouldn't trust it. At the dealer i saw a sales person do juet that with a vtl 150 much the the chagrin of several tubes. I just switch the power off on one mono amble over to the next switch it off then go back to the first, switch mode and power up and then go to the other. about half a minute total switch over time with no problems.

I pretty much concur with the above opinions. I always found triode nice for acoustic blues, small scale jazz with an emphasis on acoustic music, vocals. To me it gives the instruments better 3-d presence. Once the music gets complex or needs a boost in the bottom end the tetrode is a must, even for small 3 piece blues bands that still rely on a solid thump to make it all work.

Recently a friend and i sat down with a couple of bottles of good cab and proceeded to test the limits of my MB185s and neighbors. He has listened to tons of live music but relatively little high end audio. His unsolicited opinion of triode vrs tetrode was that the triode tended to sound more like the music was being beamed at his head while the tetrode had a more spacial ambient sence about it. I had switched modes based on my preferences and recieved that responce. We then spend the rest of the listen session doing a lot of switching. Overall his preferences tended to be very recording specific rather than music type. It was interesting to get a non-audiophile biased opinion. I also tried to get his feel on vinyl but we were to far into the cab by the time that experiment rolled around

Zaikesman, you description of the physical qualities of tetrode verses triode are exactly what i would say...only completely opposite. I agree with you where you say tetrode has a greater dynamic range and has more purity and naturalness. But i find triode to be more detailed, have a more focused images, tends to reveal more high end detail with a little less body, all characteristics you attribute to tetrode. Interesting.

Doh! I did indead mis quote you, but i do agree, as you noted that triode is more natural and pure. It appears that I forgot to add "triode" at the appropriate place.

As to our other observations being 180 out, that's strange because we both are apparently hearing the same things but in the opposite modes and have a similar overall impression of the two modes (ala triode being more natural). The question that arises is: are there system dependancies that are driving our observational differences or are we describing the same thing differently. If the latter it would seriously cause one to take all reviews with an even larger grain of salt due to the subjective listening impressions being overprinted with imprecisly defined descriptions. Just some philosophical head scratching.

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

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.