I hate to say it, but now I think maybe I like my amp in ultralinear mode versus triode

LOL, those that agree with you are rational and those that disagree irrational. Argument from incredulity is a logical fallacy.

That's not what I said viridian.  What I said is that there are two rational conclusions that can be drawn from the information provided, and that for ghdprentice's sake, I hope it's one conclusion instead of the other that he is experiencing.  If you think there are other rational, not irrational conclusions, that can be drawn, then please, tell us what those are. 

That is hardly all that you said, but I appreciate the back pedal. We will agree to disagree and leave it at that, logical fallacy, or no.

From a design perspective, ultralinear taps must be added to an output transformer at the manufacturing stage. They have a cost associated with them, a PP output transformer designed strictly for triode operation would be less expensive without the UL winding. So if the manufacturer spends the extra money for a UL winding they would, seemingly, have optimised it for the tube type and circuit.

No back pedal. I’ve told the forum what I said; please tell tell us what you think I said.

@ghdprentice: I, and presumably atmasphere, and all other rational thinkers, would rationally conclude that your amps are optimized for triode topology...and, necessarily, that the ultralinear topology was added, presumably as a gimmick, to presumably, attract more purchasers. Let’s hope so anyway, as the other option is that the amps are not optimized for either topology and that you and the other folks just like the same not optimized topology over the other not optimized topology.

That is exactly what you said.

So if the manufacturer spends the extra money for a UL winding they would, seemingly, have optimised it for the tube type and circuit.

@viridian This assumes that the manufacturer knew about the patent and designed according to it rather than the tradition that developed trying to get around it. In a way, David Hafler might be the one responsible for that; he was one of the inventors when he was at Acrosound, to whom the patent was assigned. When Hafler moved to Dynaco the patent didn't go with him but he knew full well how to get around it. So its reasonable to assume that Dynaco OPTs are not optimized.

So a rational thinker, in possession of that knowledge, might conclude that the UL taps were improperly placed, causing the triode setting to work better. However, a rational thinker might also wonder if the OPT had windings to accommodate the difference in the plate load impedances required since that value for a given tube is different for a pentode as opposed to the same tube wired in triode.

I'm certainly wondering that. Whether I'm a rational thinker is another matter.

@emergingsoul , at on or about the 16th reply to this thread, at my request, @mulveling  did provide a description of the different (triode, ultralinear, and pentode) topologies..

@mulveling 

Out of all the possible questions to be asked on this forum, this is one I would never have expected before now. No, UL is not solid state. And it’s about as much a marketing term as "gravity" or "electromagnetism".

You have a way with words.

Thanks Ralph, you are always a breath of fresh air.

Yesterday afternoon going into the evening I put five more hours in in the UL mode.  I note a "fuller" presence in UL that I was getting in triode mode.

I won't go  blow by blow into yesterdays session, but I'll mention a couple of things that stood out (from yesterday).  I have been planning (for some time) on listening to to a couple of SACDs (Jacintha Goes To Hollywood and Patricia Barber/Modern Cool) but I never made it past digging out red book CDs that caught my eye and then my ear.  I saw a movie a few nights ago on TV that reminded me I owned Chris Isaac/Heart Shaped World which I bought in 1990 but never listened to all the way through.  Probably over produced for my usual tastes, but the sound was was room filling and it sounded quite good.  I bought Brandy Carlile/The Story quite a few years ago because I heard her sing The Story on my car radio, and I thought that I would like to hear the choruses in which she was literally screaming on my system, which, in theory should sound way better than  the AM/FM radio in whichever vehicle I was motoring about in at the time.  But the playback on that one never met my expectations.  I put in that CD (The Story) yesterday specifically to hear her sing The Story, and I can honestly say that I was struck by the visceral impact of the choruses more in UL than I had been in triode.  I actually wound up listening to the whole CD, and it does have a nice sound.  (It was one of the CDs that kept me from getting to those two SACDs by Jacintha and Patricia Barber, but I am leading off with them tonight.)

However, with all that typed, I will also say that my initial reactions could be the "new toy syndrome"; I am admittedly prone to that infection.  Also, as noted before, my hearing is changing and not for the better, I have introduced different speakers to my system, my system now resides in a different room than it did when I first set it up, and the way I listen has changed significantly over the years..

@immatthewj Not exactly. But its likely that one tube type in that list will perform better than others. That’s a bit different from saying that it will ’work’; sure it will play but the output transformer should be optimized for a particular tube.

@atmasphere , although I do not understand circuit topology what you write does make sense. I’ve often found that tools that are advertised as fulfilling multiple functions do not work as well as a tool that is designed to perform one specific task. And hand tools are much simpler to understand and work with than circuits are.

As far as rolling tubes, I am not trying to speak for Dennis Had, but from reading the writeups he provides for several of his products (including the V12, from which I sort of recently quoted the manual), I sort of get the impression that he likes tube rolling. I remember reading one of the blurbs he wrote for one of his fairly recent SET amps, and he described it as (I belive the words he used were) ’a tube roller’s dream.’ Anyway, as far as the V12, after reading through the recent posts I am going to assume that it was "voiced" (I’ve read that term elsewhere) for the EL34 and after reading the recent responses on this thread, I am not going to mess around with other tubes. (Although I do have three different quads of 6550s for another amp that I am not using right now, and if worst came to worse, I could drop one of those quades in and bias the amp for two tubes per side). I’d also note that in the manual, Mr. Had writes about the virtues of the triode circuit toplology, and from what he writes about the V12, I am assuming that he includes the V12 in pushpull. Meaning that I guess he probably "voiced" the V12 in triode, but for at least the present moment, I am preferring UL.

@xenolith , I was going to jokingly type thgat you are a buzz-kill, but a lot of jokes are not taken as such. In reality, I wouldn’t be surprised if you are correct. I don’t have much of a grasp on the subject of circuit topology and back when I was setting up my system (the ’90s), I didn’t have a computer and didn’t know about A’gon, and what I learned was from reading Stereophile, what dealers told me, trial and error, and what manufacturers and their tech guys told me when I called them to ask questions about their products.

Anyway, if I NOW had the wherewith all to start completely over from the ground up, I would do a lot of things differently. However, I retired early and I made a few bad life choices before Idid, so I am probably going to find a way to try to be as happy as I can with what I have. But I will add that before the V12 I had a couple of strictly UL products, including a pair of ARC VTM120s which I have referred to previously in this thread, and if they were more relaible than they turned out to be, I’d still own them, and although aural memories (at least mine) are often flawed, going from the ARCs to the V12 was, at best, a lateral move. As far as the sonic presentation, that is. But when I flip the switches to turn the Cary on, I do not have to cross my fingers, and that is worth something.

@decooney , I really liked the sound of my V12 with the Ruby branded EL34s it came with, and I am assuming that those were the same as the Chinese tubes you just referred to.  I don't think that I will be rolling any tube types other than the EL34s.  In an emergency I guess I might try rebiasing to two tubes perside, and trying those old NOS Tung Sol 6550s I got from Andy way back when.  Maybe.

I also remember a couple of conversations we had about biasing that amp.  I di try backing it way down, and I didn't think I liked it at the time.  But maybe that was a preconceived notion I had that low bias couln't be good.  At the moment I have both sides set at just under 270.  As long as I am experimenting with different things, I'll back it off tonight.  I was thinking about 240 mA aside and going from there.  Also, when I last experimented with backing the bias off, I was listening in triode, and triode was another of my preconceived notions that I turned out being open to rethinking.

Thanks for taking the time to replay, you always offer a lot of insight when answering my V12 questions.

@mulveling

@gs5556

@atmasphere

Enjoyed reading all your comments to explain this technical area. Very difficult to understand things without a diagram and that’s what’s needed here.

I think the term ultra linear is marketing in nature and I dare say most people have no clue what they’re buying when they do. I remember loudness controls on a receiver I had a while back and was curious at times and clearly pushed more power through the circuits. It’s all about compromise which can be understood without getting terribly technical and my decision was to do biamping of a solid state and tube amplifier. At least the harmonics are more favorably affected and I do really like isolation of tubes in the upper area and let solid state handle the heavy duty stuff below. It seems to be working pretty well so far.

But again it would be kind of nice to see a diagram of all this to better understand the differences between modes of operation which on this amplifier tend to be switchable so easily which always raises skepticism in my tiny mind. But ultra linear does drift more toward solid state and isn’t that what we’re really saying overall after all

@immatthewj Also, when I last experimented with backing the bias off, I was listening in triode, and triode was another of my preconceived notions that I turned out being open to rethinking.

Thanks for taking the time to replay, you always offer a lot of insight when answering my V12 questions.

Does your V12 still have the original Audio1 coupling caps installed in it?

Worth flipping it over when you remove the tubes, pull the cover and check. Installing really good caps in that amp brings it to another level of enjoyment.

Does your V12 still have the original Audio1 coupling caps installed in it?

@decooney , no, it came with Jensen caps, and so far that is the only true failure (one of those original caps), and I won't go into the details, but I think that may have been my fault.

Anyway, I think you and I may have discussed this as well; I replaced all four caps and went with the Mundorfs. (I'd have to look at the receipt, but I am pretty sure they were the most expensive Mundorfs that PCX was selling at the time, so "air oil supreme" or something like that, but I'll check the receipt tommorrow and get back to you.  I think I remember you telling me that the caps I picked were okay, but would not have been your first choice.))

@emergingsoul

I think the term ultra linear is marketing in nature and I dare say most people have no clue what they’re buying when they do.

But ultra linear does drift more toward solid state and isn’t that what we’re really saying overall after all

I am not sure whether you are just troll posting, but assuming that you are not, do you also feel that, for instance, single ended triode is also "marketing in nature"?

the differences between modes of operation which on this amplifier tend to be switchable so easily which always raises skepticism

Are you also skeptical about the sonic differences between different vacuum tubes because it is quite easy to swap them out? Adjustable feedback? For that matter, do you believe that possibly the whole concept of vacuum tube gear is also a marketing ploy, and underneath it all lies solid state circuitry?

Just curious.

@immatthewj here are the 80510 units I put in the Cary V12R and Quicksilver Mono 120s.  From the Partsconnexion site.  

Mundorf Capacitor 0.22uF 1000Vdc MCap® Supreme EVO SilverGold Black SESG Series Metalized Silver Gold Polypropylene Axial

SKU: MUNDORF-80510

MSRP: USD $59.88

Unit of Measure: Each

@immatthewj

A technical reference to triode in marketing literature makes sense, it’s not sexy. Ultra linear Whatever it is that it does is a sexy marketing term. If it’s switchable that’s probably discouraging a lot of people from taking it seriously especially in an amplifier.

The manufacturers don’t really provide much info on what’s being done. A nice schematic would be nice because it does get involved.

Audio manufacturers do an abysmal job explaining what their products do. It’s a mystery box and you really have to dig in to figure it out.

There are clearly harmonic changes with tube amplifiers that are especially appealing unless you enjoy clinical accurate Music which is less than enjoyable a lot of times.  It's all about the quality the recording after all and there's only so much you can do to improve it and that really really sucks that they didn't get it right to begin with we have to spend a lot of money to enhance and bring out the best of what it has to offer

@decooney , I found the receipt for the Mundorf capsI bought from PCX:  they were the 71552s (0.22 uF 1000 Dc Supreme SilverGoldOil) @ 52.68 each.

A technical reference to triode in marketing literature makes sense, it’s not sexy. Ultra linear Whatever it is that it does is a sexy marketing term. If it’s switchable that’s probably discouraging a lot of people from taking it seriously especially in an amplifier.

@emergingsoul , at this point I am almost certain that you are troll posting. Did you actually read any of the circuit-technical posts from the more tech savvy members?

Here is an article from Wiki that I do not expect that you will bother with, but I’ll post a link anyway:

ultralinear

"Ultra-linear electronic circuits are those used to couple a tetrode or pentode vacuum-tube (also called "electron-valve") to a load (e.g. to a loudspeaker).

" ’Ultra-linear’ is a special case of ’distributed loading’; a circuit technique patented by Alan Blumlein in 1937 (Patent No. 496,883), although the name ’distributed loading’ is probably due to Mullard.^[1] In 1938 he applied for the US patent 2218902. The particular advantages of ultra-linear operation, and the name itself, were published by David Hafler and Herbert Keroes in the early 1950s through articles in the magazine "Audio Engineering" from the USA.^[2] The special case of ’ultra linear’ operation is sometimes confused with the more general principle of distributed loading."

And apparently, if you are not troll posting, you do not believe that switches could be used to toggle between two circuits, even if it was not the optimal way of achieving either circuit?

Meaning that I guess he probably "voiced" the V12 in triode, but for at least the present moment, I am preferring UL.

@immatthewj IMO 'voicing' is a bad practice. I very much doubt this amp was 'voiced'.

I think the term ultra linear is marketing in nature and I dare say most people have no clue what they’re buying when they do.

@emergingsoul The term 'ultra-linear' was used to describe the invention that is the subject matter of US patent number 2710312A. You'll see it used in the text of the patent. Its an accurate description of  the time about a break thru in amplifier technology. Diagrams of how it works are at the link.

Loudness controls have to do with how the ear's frequency response changes with volume. Its a tone compensation.

WRT UL, It can be made switchable by having a switch connect the screen of the power tube to its plate as opposed to the tap on the output transformer.

Its not a marketing term any more than the word 'triode'. Its part of engineering lexicon.

Ultra linear is a sexy term used by the manufacturer. Cary has not done a very good job to explain it on their website.

I think they’re taking advantage of the technology to promote something that is questionable as to sonic credibility. It’s not a very popular feature. I have never seen it before. Most people who buy this have no clue what it actually does only that it sounds different. It’s a rabbit hole and it’s clear when you read through this thread how confusing it is. Again a nice diagram would be nice.

Genius is the ability to explain involved complex things in a manner that can be understood.

@emergingsoul ... Audio manufacturers do an abysmal job explaining what their products do. It’s a mystery box and you really have to dig in to figure it out. ...

 

Ultra linear is a sexy term used by the manufacturer. Cary has not done a very good job to explain it on their website. ...

What you are not aware of and dont seem to understand is these amp circuits and designs were intentionally kept secret, undocumented, not openly shared by the original owner, founder, designer - so others dont try to cheat, steal, copy them.

For your awareness, its done this way on purpose. As you research more, you’ll learn more about what these circuits of strapped triode, ultralinear, actually represent beyond the uninformed nonsensical marketing jargon you are trying to make it out to be. When you own and use one of these amps, you'll understand more that its not just marketing.  They truly can sound different, and people pay up for them just to own one.  

@atmasphere , I probably used the term "voicing" in error. I probably do not even have a layman's grasp on the subject that we are discussing, but at least I keep a relatively open mind and I am always trying to learn more.  What I meant was that, although I cannot speak for the designer of the V12, was that maybe he probably designed with triode being the optimal mode and the EL34 being the optimal tube, even though he also designed it to be switchable to ultralinear via six toggle switches and that besides the EL34 he lists a few other octal tubes that he says can be used?

As an aside, back in '20 I contacted Jim McShane about retubing that amp, and I had heard so much about the Gold Lion (reissued) KT77 I told him I was interested in them.  He emailed me back and gave me the impression that he wasn't crazy about selling me anything but EL34s for that amp.  I emailed him back and said that 'you know more about it than i do, so if you think I'd be happier with EL34s  than GK KT77s, let's do EL34s.'  He emailed me back and said something to the effect of, 'That's not what I said.  The GL KT77 is a fine tube which I can sell you, but there may be issues with biasing it in that amp.'  Which, with my limited understanding & knowledge of the subject, was good enough for me, and I bought a dozen of the reissued Tungsol EL34Bs from him, which I am still running today.

Anyway, I appreciate the time you take explaining things on this site.  

@immatthewj having dealt with both of these characters on amps, different tubes, options, I’ll say you are a bit on your own until you partner with a great local tech who can open up these amps and tell you what’s really going on inside of them.

I’m always leary of tube resellers who are likely trying to sell you what they have on hand or can get easily vs something they dont’ have on hand or need to order or cannot get so easily during different cycles of tube availability any given month of the year. Yes, and, Dennis did and still does "voice" his amps [in his own mind] trying different circuits, tubes, transformers, and more to achieve a different sound that he likes. Having owned various Cary Audio and Inspire by Dennis Had amps, all of them sounded different in triode, strapped triode, ultralinear modes too. And, my other ultralinear circuit mono tube amps sound different yet again from the former Cary and Inspire amps. Voicing, Marketing, whatever - back to listening to be the final judge of what you like and hear for your own system :)

@emergingsoul

Ultra linear is a sexy term used by the manufacturer. Cary has not done a very good job to explain it on their website.

ultralinear is a term that is not limited to just one manufacturer, kind of like AC or DC is not limited to any single manufacturer.

I think they’re taking advantage of the technology to promote something that is questionable as to sonic credibility. It’s not a very popular feature. I have never seen it before

I am not sure what you mean by all of this, but just because you have never seen it before doesn’t mean anything. Read the Wiki article I posted the link for. I think it states that the UL circuit was originally patented in 1937. As far as being switchable from one circuit topology to the other, that’s nothing new either. For all the good that it may not have done me, I subscribed to Stereophile throughout most of the ’90s up until ’02 and I’ve read reviews of more than one manufacturers amp that was switchable. What sticks in my mind were a pair of VTL or Manley Labs (I get the two manufacturers mixed up) that were switchable between triode and either ultralinear or pentode. Earlier in this very thread, in a part of the conversation with @decooney , we were talking about an amp called The Baron which was manufactured in the late ’90s by Mesa (dual monoblocks in one chassis with adjustable feedback and a dozen 5881 output tubes); the circuit(s) were switchable between triode and what Mesa was calling pentode, in thirds, and for that, Mesa was using ONLY TWO toggle switches PER SIDE. One switch controlled two pair of tubes, and the other switch controlled one pair of tubes. In other words, both switches could be in either triode or pentode, OR, one switch could have one pair of tubes in triode while the other switch would put two pair of tubes in pentode--OR vice versa. For those who think amps do not make a difference in the sound . . . they should hear the Mesa baron . . . I tiook one home for a weekend and the sonic differences were significant--but not all good. I stayed with the smaller tube amp I was running at the time (another smaller Cary wired in full time ultralinear) and later upgraded to a pair of ARCs (also wired in full time ultralinear) and due to reliability issues with the ARCs (although they sounded fantastic) I bought the V12 I started this thread by discussing.

If you think that the word ultralinear is "sexier sounding" than the word "triode", I can only tell you that if you read Dennis Had’s (the designer of the V12) description of the triode circuit, you might come away thinking that triode is the "sexier sounding" term.

Seems the self-inflicted-comical poster sees the initial post heading, reads little in between, goes straight to the end, and just starts replying with whatever comes to mind to get folks stirred up.  

@immatthewj You don't have to dig deep on this one. The Dynaco ST70 is arguably the most famous ultra-linear amplifier made although all the Dynaco amps were ultra-linear.

@immatthewj having delt with both of these characters on amps, different tubes, options, I’ll say you are a bit on your own until you partner with a great local tech who can open up these amps and tell you what’s really going on inside of them.  

@decooney , well, okay, but you did tell me that the only tube you wound up using were the Chinese Ruby branded EL34s, right?  At the time I needed to retube that amp, Jim had a bunch of tubes listed in his inventory, including the GLs, which was part of the reason I contacted him for that retubing.  (The last I read he said he was retiring and prior to that wasn't going to sell any tubes made in Russia anymore.)  I was quite happy with those re-issued Tung Sols, and I will say that he gave me what seemed to be better personalized service than any other tube seller I've bought from (with the possible exception some NOS small tubes from of Andy from Michigan).  Jim would send me an email every day or so telling me how the matching process was going, and as I recall, it took a few days or maybe even a week until he emailed me telling me he had two matched sex-tets ready to ship. A couple of years prior to that I had bought a dozen reissued Mullard EL34s from Viva, and it was wham, bam, thank you ma-am, and I had them, but they didn't run long at all (about two years) before the bias(es)  started doing goofy things.

Anyway, as another aside question, did you ever experiment with running your V12 configured in anything but FULL triode or FULL ultralinear?  I mean like 1/3 + 2/3s?  I know that the owner's manual says only run FULL one way or the other, and after the amp arrived to me I talked to Kirk Owens about it, and he didn't sound too crazy about the idea. . . .  I know that the Stereophile review said it was okay, but I always felt better about defaulting to what the manufacturer said than what Stereophile said.  I think I remember that I may have tried it for a real real short time, but I do not remember how I felt about it, meaning it was nothing at all close to as dramatic as the Mesa Baron was.  

In audio reproduction, linear is sexy.  Ultra linear is ultra sexy.

In audio reproduction, linear is sexy. Ultra linear is ultra sexy.

If you say so; however, neither word strikes an erotic chord for me.

WRT UL, It can be made switchable by having a switch connect the screen of the power tube to its plate as opposed to the tap on the output transformer.

Thank you for that, @atmasphere , that's a nice nutshell that even a layman (at best) like me can just about grasp.

@immatthewj to answer your questions, after I recapped with those specific caps, and tried different designs of silver-over copper and more pure copper interconnects between source/preamp, preamp/amp, in my case, and for my particular speakers it was a dead-on match for my taste and ears. Not to over think this too much - I simply enjoyed those particular EL34s at the time. I figured out who was making them for Ruby lable brand [at that time] and the sound is where I wanted it to be, for me. So, I did not change to different tubes, although I came close to trying the reissue Genelex KT77s regardless of what anyone says about them, and the only reason I did not do that is I wanted to try separate tube mono blocks with a dedicated ultralinear circuit, double the transformers and power caps instead - with my speakers. Someone really wanted to buy my V12R at the time, and I struggled with selling it. I sold it only to try the monos as an experiment to run with my speakers [trying different amps with my own custom speakers I build/built], to install the exact same caps, and even better Nichicon power caps, and compared from there. Everything was how I needed it on the V12R. Had I kept it, I might have tried KT77s, and once again, keeping bias down to 200-210 per side, max. Sound find, tubes last longer. btw, I’m trying new input tubes this weekend, on the monos to try and model one input tube set I had on the Cary V12R, trying to bring the sound of the new amps closer to what I had with the V12R prior. Just testing, trying, listening.  

Oh, and No, I did not want to mess any more with the prior amp or the switchable circuit or trying to un-switch it, left it as is, it sounded great as-is, and decided to move to dedicated ultralinear mono amps.  This has been yet another chapter of learning, upgrading, listening and has paid off nicely too fwiw.  

@emergingsoul  wrote:

Again a nice diagram would be nice

@atmasphere  had previously written:

@emergingsoul The term 'ultra-linear' was used to describe the invention that is the subject matter of US patent number 2710312A. You'll see it used in the text of the patent. Its an accurate description of  the time about a break thru in amplifier technology. Diagrams of how it works are at the link.

Again:  

Diagrams of how it works are at the link.

@immatthewj 

Yes the link was very helpful. It's good that I am very intelligent and can understand these things. Thank you

Yes the link was very helpful. It's good that I am very intelligent and can understand these things. Thank you

Yes, that is good.  I am happy for you.  But do not thank me; thank @atmasphere ,  as he posted the link a few posts before you said you would like to see a diagram.

Regardless of what we each think of the term "UltraLinear", and its alignment on the good-versus-evil spectrum, I found the following diagram most succinct and easy to digest. It’s from a web search that hits el34world dot com.

Note the wiring in the orange boxes (these would be easily controlled with switches), and the "UtraLinear" taps coming from the transformer primary, to the right - these UL taps are the legs that are positioned (symmetrically) between the 2 outer taps (each tied to their corresponding push/pull tube’s anode plate) and the center tap. These particular taps are disconnected in triode and pure pentode modes. They are connected to the corresponding tube screen grid in UL mode.

I assume the exact % of the UL taps’ positioning between outer taps and center tap is what’s at issue for "optimal" UL loading to a given output tube type - as circuit gurus like Ralph have pointed out.

In pentode mode, both tube screens are tied to the center tap. In triode mode, each screen is tied to its own tube's anode plate. 

Thank you, @mulveling !  I have printed that as well.

You asked for a diagram, @emergingsoul , it appears as if your wish has been granted a couple of times over.

Circuit topology of appliances sexy? I would not want to clean your Roomba. 

Circuit topology of appliances sexy? Someone needs to go on a date....with a human.

@viridian , going on about 25 years ago I was buying some 12AU7s and 6922s for a preamp and amp I had, from Andy from Michigan. I probably made two or three phone calls to get the deal done, but in the course of those calls and conversations, Andy got off the topic of the tubes he was selling me and got to talking about a push pull amp he had recently restored or built (I wish I could still remember his exact words) but it was just a massive amount of class A wpc and when he said something about ". . . liquid fire coming out of the . . ." his tone of voice was almost orgasmic.

Your post made me think of that.

Andy Bouwman, Vintage Tube Services? Have not heard that name in decades. Thank you.

Yes, @viridian , that was the Andy I was referring to. I enjoyed talking to him. Somehow he got on the subject of amps and the people who designed those amps that he didn’t care for. I won’t mention the names, but as we were talking about the amp, I said (and I do remember this word for word), "well, with the ____ I guess you get a lot of bang for the buck," and he replied with this kind of crazy laugh, "Hoo hoo hoo, or some times just a lot of bang!" And I remember him laughing some more. I don’t know why my memory for certain detail that doesn’t really benefit me in any way is so good, there are subjects that if I could have remembered them as well actually would have done me some good.

Optomized topology is a good point and also a good argument for buying an amp with a single topology because you know it's optimized for it.

@immatthewj I have a highly modified version of that amplifier and you can actually run combinations so for example.

UL

T

UL

or

T

UL

T

(I used the amp for mastering for like four years and it's been sitting around so if someone is interested in a very nice example, I'm happy to sell it for a low cost deal) 

@mulveling 

A wonderful diagram. Very helpful. The accompanying commentary is helpful although back-and-forth discussion to further clarify what's going on is always good.

It's an awareness exercise of all that goes on under the hood.  

When Ralph and others talk about "optimizing" the amp for UL or triode mode, one thing they’re talking about is maintaining appropriate levels of feedback for each topology (assuming the amp uses global negative feedback). Switching from triode to UL increases the gain of the output stage. Switching the other way, from UL to triode mode, will decrease the gain. This affects the level of negative feedback the input stage will see. Let’s say an amp is optimized for UL mode. If you switch to triode mode without changing anything else in the circuit, you *decrease* the amount of feedback. I think this is often why people hear an "improvement" when switching to triode mode. You’ve reduced the amount of feedback, resulting in a sense of "clarity." The problem is, you’ve also reduced the output impedance of the amp and thus reduced the amount of control the amp will exert on the speaker. So the other comment you get is that bass sounds "looser."

Conversely, then, if an amp is optimized for triode mode, switching to UL mode will *increase* the feedback, and this may detrementally affect the stability of the amp as well as the sound.

Some "switchable" amps will include a circuit that changes the feedback network for each mode, thus "optimizing" the feedback circuit either way. Whether the Cary amp does this or not is a question for Cary.

But more to the OPs point, I have built amps both ways and have always preferred UL arrangements, sonically speaking.

For those who want to understand a bit more about these different topologies, there is an excellent article geared for the layman here:

https://oestex.com/tubes/ul.html

And if you want to better understand the issues of "optimizing" an amplifier for various modes of operation, there’s a slightly more technical but superb overview offered by Dave Gillespie over at Audiokarma:

https://audiokarma.org/forums/index.php?threads/regilding-the-gilded-lily-heaths-w-2m.767851/

Even if you stop after the short history of feedback amplifiers Dave provides, you’ll have a better grasp on how your own tube amplifiers work!

The "Gilded Lily" Dave refers to is actually the amplifier I build for myself, using a modern copy of the original Peerless output transformer. This is where, for all intents and purpose, the "ultralinear" configuration is in every way preferable to triode operation--to my ears, anyway. ;-)

I'll also add, in reference to "marketing," that IMHO a "tube-swappers dream" is definitely a marketing ploy, in that there is no way an amp like that can be truly optimized for each tube--as Ralph cogently points out.  I don't believe there's any harm being done here, but anyone with a technical understanding of tube amplifiers (and I'm barely on the periphery of that circle) will shudder at the idea of a "one-size-fits-all" amplifier. ;-)

Shudder is right.  Thank you for your excellent contributions dogeared.

@dogearedaudio , I just took a look at the specs listed in the V12 owner’s manual and under feedback it says "zero."

I do remember on another "switchable" amp I referred to, the Mesa Baron, on the back panel there were knobs to adjust feedback. I do not recall playing around with that particular adjustment during the two days that I auditioned that amp.

As far as "tube roller’s dream", I should clarify that I dredged that up from my memory (which is USUALLY pretty good) but since I cannot find the blurb for whichever amp it was, I probably should not be providing a designer/manufacturer’s quotes that I cannot find to reference back to.