I agree with your assessment. There are some surprises, however. For example, certain Reggae pieces (Bob Marley, Rastaman Vibration) sounds better in triode, not tetrode (as I originally thought it would). Vocals are a lot clearer, and it sounds more real, live.
On the other hand, take Vivaldi's Four Seasons with Salvatore Accardo on Philips, and it sounds better on tetrode (more liquid, smoother, soaring highs on the massed strings), at least to my ears. Weird. |
Hi Frogman,
thanks for your response. I'll try the German Amperex or Telefunken 12AT7, that's a good idea.
But what about the 6350 tube (phase splitter)? Any suggestions there?
And the output tubes (Russian 6550C) are probably ok, right? (I don't think you can change them anyway, even if you wanted to).
Right now the rule of thumb for me is: Anything from solo instrumental, up to seven or eight players, use triode. Anything above, use tetrode (this is also what T_bone mentioned above).
BTW, i use B&W N803 speakers (90 db sensitivity). |
Frogman:
whew! I appreciate your insights. Lots of things to try out when it becomes time to re-tube, that's for sure. Right now, I'll enjoy the sound and definitely check out the power cords, and perhaps the other two tweaks you mentioned. Again, thanks! |
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. |
My MB-450 have the MIT caps, I'm not sure if they differ a lot from infini caps in terms of sound reproduction.
I agree, power reserves are crucial. (I just find it astonishing that 220 watts for small-scale music might not be enough). However, all of the clues certainly point in that direction. And I'll give the Sonny Rollins "Way out West" a spin as well in both tetrode and triode. That should be interesting.
So, what to do? Get the MB-750s, or more efficient speakers, or keep everything the same and listen to tetrode mode? The audio hobby just doesn't appear to have an end to it. |
Thanks. I will, for sure, look into the infini caps. This seems like a logical, first step to take. I really appreciate the feedback from everybody.
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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. |
I feel like a complete fool, but I recently plugged each mono block into its own dedicated outlet, and man, what a difference! Now tetrode and triode sound a lot more alike, and I actually prefer tetrode for 80-90% of my listening.
Tetrode sounds perhaps "grittier," but more real! I certainly agree with Zaikesman that with tetrode there is more extension, and that the frequency spectrum is flatter. This is important to me, as I can lean back, listen, and there is nothing missing (highs, mid-range, lows, everything is there, and nothing jumps at you - - just like in the symphony hall). The soundstage is incredibly linear and extends well beyond the speakers to the left and right (but is also deep).
Conversely, with triode, I feel that the midrange is accentuated. Vocals are clearer with triode, yes, but over the long haul, it's not as involving (it get's a bit "glassy" and the soundstage is smaller than with tetrode. Actually, the soundstage with triode stays beween the speakers, and it's more "curved."
My experience is that the db difference for equal loudness is maybe 1.2 to 1.5 (i.e., triode needs to be set at 1.2 to 1.5 db higher than tetrode, which is also easy to do with my preamp (Levinson 380s).
I agree that it would be nice to keep tetrode the way it is, but also have triode's better harmonic structure and inner detail. Why can't VTL do that? Hopefully, they will at some point in time. |
Yes, the outlets are separate, dedicated lines @ 20 amperes each. It is funny we have the same preamps. My speakers are B&W 803 Nautilus, hooked up with Transparent super Bi-cable speaker wire. I also use Transparent super interconnects, and my digital source is Mark Levinson 390s. Good sounding system, very lively, I like it now (but it took me a while to get there)!
BTW, your thread is interesting, thanks! |
Zaikesman:
I'd be curious to get your report on the KT-88 tubes vs. the 6550s. I called VTL a couple months ago and they advised against any tube-rolling (at least for my amp). So long. |
As I stated above, for me it also Tetrode now (90% of the time), it just sounds better. As an aside, I understand that there is more negative feedback with tetrode (about 6dB or so), and some people (whose opinions I generally respect) claim that negative feedback is BAD, no matter how it is applied in the circuit. So I'm a little baffled why Tetrode would sound more real in my system, but it does. Go figure. |
On my MB-450 (and they have plenty of power), I now only listen to Triode with solo instruments (or solo voice). For everything else, Tetrode is far superior in overall satisfaction. Even with small ensembles (duos, trios, quartets, etc.), Tetrode gets the timing right, the individuals come together and really play as a group.
As an example where this is easy to hear, try Brahms piano trios, e.g., Trio No.3, op. 101, Fontenay trio (on Teldec), first movement, when the piano gets really hammered. In Triode mode, the piano is just too loud, reverberates, is simply overbearing, and the overall melodic structure gets lost. With tetrode, what a difference. Sure, the trio is farther back in the room, but the melodic structure is intact. And it puts a smile on my face!
Happy listening. |
Hmm . . . good points, Zaikesman. I've never listened to the MB-750 in triode mode in my room, and they could certainly sound better than the 450 in tetrode. Who knows?
But the comparison here is tetrode/triode for a given unit, and yes, maybe that's unfair to triode (with only half the power). However, listening to small-scale ensembles shouldn't tax the power requirements too much.
As far as your swapping of tubes is concerned, do you need to do anything special before you swap KT-88s for 6550s in your MB-185? I'm wondering if I could do the same, if I had the urge to do that at some point in time. And what did you do with your input/driver (phase-splitter) tubes? Did you change them as well? Just curious. |
Zaikesman: Thanks, I'll do that. Rechecking the bias is pretty easy to do and doesn't take much time. I guess all I wanted to convey that triode mode (with new tubes) has an incredible immediacy and clarity, which I didn't experience before. |
Yeah, that is somewhat strange. But everyone needs to make a living, I guess. I emailed VTL about prices but haven't received a reply yet (maybe because I bought my amp used, so I'm not exactly a priority customer for them).
On another note, I listened to Sonny Rollins "Way out West." Here is my take: Everything sounds more similar in tetrode vs. triode than on the Brahms piano trio No.3, mentioned in a previous post (maybe because that piece has more of a dynamic range?). However, track 4 (Wagon Wheels) does sound better in triode (at the same loudness settings), even ravishing, especially at the beginning, but maybe it is almost too pretty. On other tracks, especially track 1 (Old Cowhand), I can make the bass lines out better in tetrode. But from the midrange on up, triode preserves the harmonic structure a little better, and there is more air between the players (if I don't crank up my pre-amp too much).
It's almost as if triode makes the music slow down a little, and you can hear more into the internal fabric of the instruments. In tetrode, everything appears a little faster, with better rythm. I noticed I foot-tapped more in tetrode mode, and listened more closely in triode. |
Zaikesman: Isn't that a pain? Flipping a switch on the back of the amps is one thing, but unscrewing the covers, pulling out the two input tubes, and replacing them? Or do you leave the covers open? Maybe, in that case, it is not too bad.
Well, anyway, that's an interesting thought. Enjoying the music is what this is all about. |
Update: I just replaced all tubes (input, output, and driver) and I must say that now, triode is a lot better than it used to be. In comparison, tetrode is a little hazy and distant. But triode is crystal clear, and now, for example, the the above mentioned Brahms trio is unbelievable, with fantastic rythm to boot. Also, piano is fantastically present. Take Richter's performance of Beethoven's Appassionata sonata on RCA. You can hear every tap, all the hidden gems, counterpoints, etc. Amazing! And now triode (with new tubes installed) has the power to preserve the waveform, as that piece has incredible dynamics, from ppp to fff.
So, maybe this is what happens over time: as the tubes age and lose power, triode loses its magic, at which point tetrode sounds relatively better. Could it be that simple? |
Update: Tetrode/triode mode appears to be speaker dependent, too. I recently switched to B&W N802s from N803s, and with the Nautilus 802s, I'm back to tetrode for most of the time. Those babies like power, and triode is fine only if the dynamic swings in the musical fabric aren't too pronounced. Tetrode gives a much deeper and wider soundstage, and preserves all of the waveform; which makes for an unflappable presentation.
Well, anyway, I thought I'd post this, I'm just glad VTL provides both modes. With other speakers, it will be different, no doubt. |
Zaikesman: thanks for the above, informative post. I'll try that, as this will be a more "fair" comparison. But in any case, I suspect I will continue needing to run with full banks in tetrode, unless I upgrade to a MB-750, or to the Siegfried (yeah, right!).
I also agree with you that being able to change the sound at the flick of the switch is perhaps "unsettling." But with other amps which don't have a switch like that, the problem just isn't that apparent, but present nonetheless.
Any amp, whether tube or solid state, has a certain sonic signature, let's not kid ourselves. So the VTL amps have two sonic signatures, that's all. |
I'm not sure whether or not the upgrade of the input stage to the differential design has any sonic benefits IF one's cabling is all unbalanced, single-ended, with conventional RCA connectors. But it does make a difference if you're running balanced components with XLR connectors (or so I've been told).
Anyway, with my setup, which is unbalanced, it probably doesn't matter. (And in my system, unbalanced actually sounds better, there is more of a texture to the music, whereas balanced conveys a more bland, "bleached-out," sound. I gleaned this from having compared Transparent super unbalanced to Transparent ultra balanced - - but this was, of course, with the old input stage). |
