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 I need to slightly amend a couple of the (mis)impressions I seem to have left from above.
Hgabert refers to agreeing with me that "with tetrode...the frequency spectrum is flatter". Yes, tetrode could be called 'flatter' in that it sounds more extended, both top and bottom, but I said above that triode sounds more neutrally-balanced to me through most of the audioband, including all of the midrange. To me, tetrode is less flat than triode here, which is where it counts most. Questions of ultimate tonal balance, however, are quite dependent on partnering gear and choice of input tube.
Piezo says he agrees with me that "tetrode...has more purity and naturalness". Actually (except for the part I just omitted about tetrode having greater dynamic range, which is true, and which he stipulates to), that is what I said about triode, not tetrode - which generally seems a bit less 'pure' and 'natural' than triode, for reasons I speculate some about above - and in that respect we really do agree. |
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. |
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! |
Interesting result on the outlets - are they separate dedicated lines too? I guess your 450's in tetrode were pulling too much from the wall to share nicely. My 185's probably don't - I have them plugged into the same Power Wedge Ultra PLC I use for all my gear combined, with its lone cord feeding from the single available outlet. I haven't minded, but I may find an improvement if I ever re-situate to allow plugging into multiple lines or outlets (then again, maybe not - hum can often become worse in such installations). Freaky that you have the same preamp as me - how many guys could be running Levinson pre's into VTL's? Our slightly different impressions of the relative tonal balances between triode and tetrode could be because of our different speakers, and also because of different tube and cable choices. I've recently done some switching in the tube department, you can read about it on this archived thread. |
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. |
I own MB-185's, powering Thiel CS 2.2's (not the demanding load that some associate with the brand - 8" woofer and fairly flat 4 ohm impedance with well-behaved phase angle, average sensitivity of about 87dB).
My general observations about triode vs. tetrode - the inevitable variations in recordings that cause disk-specific preferences aside - go like this:
Triode: Superior in only three areas, but three of the most important areas - tonal balance, harmonic structure, and audible distortion (within its dynamic limits) on transients.
Tonal balance: Triode has a more neutrally-balanced tonality throughout the heart of the audio range. Tetrode is is brighter and less evenly-balanced in comparison, with a relative lack of lower-midrange/upper-bass fullness combined with an overabundance in the 'presence' range of the upper-midrange through the low-treble.
Harmonic structure: Triode operation reduces odd-order harmonic production, while the push-pull operation takes care of reducing even-order byproducts. Tetrode produces more odd-order byproducts, which push-pull cannot cancel, so they will heard predominantly over the more pleasing even-order series. This skews the amp's harmonic signature to yield a 'harder'-sounding emphasis with tetrode, while triode gives a more natural descending harmonic distortion with asceding harmonic order, and lower total distortion overall. This is entirely independent of the tonal balance issue noted above, which can be addressed to some degree through choice of input tubes, cables, etc. Triode will always have the advantage over tetrode when it comes to natural sweetness of harmonic presentation.
Transient distortion: Although triode won't give the dynamic impact of tetrode, and its limits are lower due to the reduced max power, transients are cleaner distortion-wise, even though they are slightly compressed by comparison to tetrode. This means that triode will deal better with sibilants and sound smoother-textured overall, while tetrode will give some false emphasis to fast-rising impulses that produces a slighly 'edgier' sound, with more emphasis on 'detail' than is strictly natural. BTW, this is just my listening impression, not something I know from a technical standpoint, and I surmise it could be the result of either intermodulation or temporal distortions.
After those three areas, I believe tetrode holds the rest of the cards, including those relating primarily to all qualities physical:
Greater extension: Tetrode has more extended response at the top and bottom of the frequecy range.
Bass definition: Tetrode maintains greater control over woofers for more bass-range detail and tonal differentiation with less overhang, although the bass often won't sound as full-bodied in tetrode as in triode.
Dynamics: As mentioned, triode will compress earlier and more than tetrode on dynamic peaks. But tetrode is also better at eludicating subtle dynamic shadings of expression on the micro end.
Soundstage: Tetrode presents a clearer, and more defined and separated soundspace than triode, which by comparison sounds somewhat homogenized and foggy. Tetrode also has greater scale.
Imaging: Tetrode presents better-focused images, triode more amorphous ones.
Resolution: Tetrode is better at illuminating decays, and combined with its clearer atmosphere and better micro-dynamic tracking, the result is more transparency to fine detail and more precise articulation.
In sum, I think the amps pass more information in tetrode, but don't necessarily present it as nicely as in triode. (Of course, all my observations are drawn by me in my system, and are therefore not to be taken as universal truths.) I do end up using the switch as a tone control sometimes, dependent on the recording. If a recording is overly-aggresive, I'll likely go to triode regardless any impact or definition I give up. Likewise, if a recording is muddy or hooded-sounding, I'll use tetrode to help pry it open, harmonics be damned.
With well-recorded material, its a little more disconcerting to me to have an amp with two distinct sounds, neither of which I know is absolutely correct. I'd love to be able to combine the purity and naturalness of triode with the control, power, extension, and precision of tetrode. But since no amp is totally correct, I guess it can't hurt to own that at least gives you an option. So on decently-recorded disks that won't penalize you too much either way, my preference is mostly determined by the type of musical material, where its inherent priorities lead me.
BTW, I often do my comparisons on the fly, sometimes with music playing. Over the past year, switching with impunity has possibly cost me two output tubes and one output fuse, but I can't be entirely sure of the causes. One thing I know is that if you are going to do this, it is vital to flip the switch as quickly and positively as you can - no half-assed indecisive or scared-acting switch-flipping. Just do it. Or don't do it - this has got to be a personal call. I've flipped hundreds of times with no problem, but who knows what'll happen next time? Oh, and to make valid comparisons, you MUST compensate for the 2-3dB volume differential between the two modes (something that's easy with my Levinson preamp's programmable muting function).
As a final thought, it's worth saying the change in modes is not a night-and-day affair - it can be pretty subtle, or pretty insignificant with certain sources. After all, most of what makes the amp sound like the amp that it is, remains the same in either position. Right now, I'm considering a coupling cap upgrade and some experiments with input tubes in order to try and bring tetrode closer to my ideal tonal balance, which for me is its biggest flaw at present.
So far, I'd say that I run the amps 80% in tetrode over triode, but when I first got the amps, the switches had been removed by a previous owner and left set on tetrode, so for almost the first of a year I had them I never heard triode. As I've gotten used to the restored switch and its effects, I find myself increasingly willing to forego some of the qualities I had become accustomed to before the repair and listen in triode. |
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. |
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 |
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. |
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? |
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. |
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. |
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. |
I'll go along with the generalization of "The less complex, the more fitting the triode works". I have VTL MB-125's and tend to keep them in tetrode most of the time... I prefer the extra gusto and sheer effortlessness. I can find triode intriguing with the right mood which usually entails late nights and some smooth jazz but I'm often dismayed by the less than agile bass if I kick up the volume to any more than moderate levels. I find the increased "3D" addicting in triode but the tetrode always gives me that extra kick. Another generality, (obvious?) : the better the recording, the more it will display the virtues of triode... tetrode can rock to much less sophistication. Oops, does that make me some kind of "Common Joe"? Oh well. Just for the record, my good friend runs his MB 450's (I've got my eye on those someday) and his Wotans (2 separate systems) in tetrode virtually all the time. "Too syrupy", and "not tight enough" being his opinion... . It's sure nice having the option though isn't it ?!! Good listening. |
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! |
The 6350's affect the overall sound less than the 12at7's do. It still pays to experiment, though. This is an American made tube and there are no exotic versions available, to the best of my knowledge. My favorites are the Tungsol's and the earlier RCA's. The RCA's that I have (two different vintages/two different internal construction), sound a bit more relaxed and romantic. The Tungsol's sound a bit more dynamic and alive, with a more prominent top end; this better suited my system. The differences are relatively subtle; but a definite improvement over the GE's that came in the amps. Try "Antique Electronic Supply" as a source of 6350's.
As far as 6550's go, I really don't have an opinion since my amps use 6L6GC's. I will say that the Sovtec 6L6's that the amps came with sound less refined than the NOS GE's that I have. The GE's are not a particularly great tube either, but in my system, a better sound. I hear good things about the Svetlana's; maybe worth a try. By the way as far as the 12at7's go, the Telefunken CCa (a super-premium version of the 12at7) is supposed to be THE tube for these amps. Very expensive, though.
Have you experimented with power cords? My amps definitely benefit from upgraded power cords. I use the old Tiffany "reds". Recommended by the Manley's themselves as the chords for these amps. This is going back several years, however, and I'm sure there are better cords out there for these amps, by now. The improvement over the stock chords was unmistakeable, however. Gutsier sound, with larger soundstage and more refinement. My amps also like to be placed on hard cone-type footers. The soft type makes the same a bit ill-defined and tubby. And finally, VPI bricks on the transformers are a very worthwhile tweak; the tighten up the sound, and make the spaces between instruments cleaner.
Good luck. |
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). |
Hi Hgabert
In my experience (Manley 200/100 Mono's, very similar circuit to your MB's)), in absolute terms, the amps always sound better in triode: much more refined sound, better detail, less grundge, etc., etc. Tetrode becomes advantageous when your system, wether because of your speakers' efficiency, or your preamp's gain characteristics, benefits from the extra power. If your speakers are efficient enough to meet all of the needs of every type of music that you listen to, at every loudness level that you listen at, with the amount of power that triode has to offer, triode may always sound better to you. It sounds like they are not; few are.
I found that in my system, with many speakers, tetrode not only allowed the speakers to play louder, with more bass, but more importantly, it let the speakers unravel complex orchestral passages, it let a string section sound like many individual players as opposed to one large mass of "string" sound; probably why the Vivaldi sounds better in tetrode. Most reggae, while "bassy", is not particularly complex music; so will probably tax the amps less. The problem became that I missed the purity and sweetness in the highs that triode offered. The solution for me was two-fold: get used to listening at slightly reduced volume; this taxed the amps (and my hearing) less, in triode mode, and experiment with the input tubes. I found that with the right NOS 12at's (for me it was W.German Amperex or Tele's), there was enough of an improvement in the detail and treble extension departments, in tetrode, to bring the sound close, if not quite, to the level of triode sound with run-of-the-mill 12at's. This allowed me to enjoy tetrode mode when I absolutely had to have the extra watts. Of course, the sound in triode became that much better also; and this is why it is called "audiophilia nervosa" :)
Good luck. |
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. |
When I first got my MB-450s, I played around with it. I managed to make it a difficult lean to get around to the back of them so I have since usually switched only once every couple of months - usually when I'm listening to large scale symphonic works or opera. The rest of the time it stayed on triode.
Recently I got a pair of MUCH more efficient speakers so have no use for the added "stomp" that tetrode provides.
FWIW, I agree that piano and almost all single instrument classical or chamber music, jazz, and vocal is better done on triode. Tetrode really shines with music with "impulse" dynamics - things like Holst's Planets, Beethoven's Fifth, above-mentioned Mahler symphonies, and good feisty operas (Carmina Burana, Don Giovanni, etc). |
