VTL Tetrode/Triode

Hello again, I agree that turning the amps off is a definite inconvenience... I'm always pondering how long to linger (off) before flicking the switch and going on again (I do the whole procedure in less than a minute) but there's always that hesitation in my mind when I click back on after running them hot for awhile... So far they've been flawless every time. I try to choose my mode and music at the beginning of my listening session just to avoid doing it although it sometimes can't be helped... I honestly think that because you must turn it off for switching modes that it actually makes sense keeping the switch on the back... This will keep unknowing fingers from flipping a mistake. In fact, when I saw the recent review of those big Neo classic Manleys in Stereophile it was seeing the switch on the front that actually brought this concern to mind. A small pilot light [on the front] indicating which mode would be a clever and convenient feature. I actually keep a small index card with "triode" on one side and "tetrode" written on the other which I leave near the amps to remind me where I left the switch positioned during its last use.Anyway, nice talking to you, maybe I'll spend a little more time hanging out with the virtues of triode a bit more... it really is fun playing with each type of sound.Happy listening.

Oops, looks like my answer didn't get posted quickly enough. Is it really true we can switch simply without a signal going through? That would be a lot easier... mute the pre and we're all set? BTW, I am driving 95 db efficient speakers (into a fairly stable 8 ohms which never drop below 6.5 or so):Silverline Sonata 2's. What my MB 125's are putting out into them is probably close to 100 wpc or so in tetrode and I'd guess about half of that in triode?... What do you guys sit your amps on? Mine sit on 2 navcom silencers [in the back] and a few sorbothane isolation feet in the front. This is all on a couple of sandwiched marble slabs (about .75 inch thick ] which sit on a pair of 6 inch speaker stands (not spiked) on the carpet. Do you think tip toes would be better than the sorbothane/navcom silencers combo?

Yes, it is true that you don't HAVE to turn the amps off; according to Manley. However, by turning them off, I suppose the problem of forgetting to mute the pre becomes irrelevant. NO SIGNAL THROUGH THE AMPS WHILE SWITCHING!

Again, I found that if the goal is the purity and detail of triode mode, that any kind of compliant isolator sent the sound in the opposite direction. For me, hard cones between the amps and sandstone slabs(on the floor) gave the tightest and cleanest sound. Sorbothane tended to blur images and make the amps even more "tubey" sounding.

I'll stick to my comments about triode/tetrode. IMO, given the same circuit, triode operation is always superior. Does one then have enough power for the speakers being used, however?

Lastly, make sure that your tubes are biased properly! This will definitely affect the sound.

Happy listening.

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

Piezo: It would be interesting to know if your evaluation of tetrode vs. triode sound changed over time (as the cab got depleted). Perhaps it wasn't recording-specific, but cab-specific, what do you say?

Just kidding, thanks for the input.