VTL Tetrode/Triode

Hi Lissnr:

All larger-scale works that I have played on my VTLs do sound better in tetrode, I agree there. For instance, with a Beethoven symphony (try Karajan's 1963 cycle with Berlin Philharmonic, 9th), triode just can't match tetrode's steady grip, with a totally steady soundstage, all instruments staying in their places, just like you would hear in the hall, especially when the chorus comes on in the last movement.

But listen to some small-scale jazz or classical, and triode just is more real. I attend live music performances quite a bit, and to my ears, there is no contest.

In fact, with tetrode on smaller-scale music, one loses the inner detail, the beauty and air around instruments, and the ambience of the recording venue. It sounds flatter and less involving.

But to each his (her) own. I just wished VTL would make the switching less of a pain. Always having to turn off the amps before switching is inconvenient, to say the least. And they should either have the switch on the front panel, or have an indicator light for triode mode. That would be nice.

I understand the new Siegfried amp does automatic switching.

Try listening at reduced volume, and I think you will find that triode has a decided advantage over tetrode, even with large-scale, complex orchestrations; the issue is simply that to unravel and amplify a complex signal, more power is needed. It's not that tetrode ever has an advantage, per se, it's that when the music is more demanding, the extra power makes up for any loss in transparency that triode provides under ideal circumstances (higher speaker efficiency). Conversely, try turning the volume up, higher than normal, while playing small cale jazz or classical. I think you will find that you lose the detail and purity.

I think that we can all agree that filet mignon is a better cut of beef than sirloin; but if the budget only allows for one pound of filet, and we are trying to feed six adults, would it not be more satisfying to buy two pounds of sirloin, than one pound of fillet. Poor analogy, perhaps, but the point is that I think that if you were to compare tetrode to triode, using something along the lines of a Klipsh corner horn with it's extraordinarily high efficiency, it's unlikely that there would be any advantage to tetrode mode; unless, perhaps, if you were trying to fill some incredibly large space with sound.

By the way, it is not necessary to turn the amps off to switch between the two modes. You simply have to be sure there is no signal running through them: mute the preamp.

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.