You should check out the "parts count" of typical, common, or high end solid state equipment and you'll have your answer.
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If direct path is preferred in the speaker by most, why the acceptance of a glass army in one's amp/preamp?Not sure what is meant by 'direct path'... But if you need a lot of power, you might need a lot of tubes to make that power. If so, they'll be in parallel, which means the signal is fed to all of them and they all work in tandem to make that power. In that particular case, the signal path complexity is the same whether one power tube is used or 20. We have a good number of power tubes in our amps because the power tubes, which are triodes, don't make a lot of power. But those amps only have one gain stage in the entire amp! That's about as direct as you can get. |
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Too many tubes? That reminds me.... https://youtu.be/H6_eqxh-Qok?t=35 Which tube do you have in mind to remove? |
Power from an amplifier is dependent on three things: the gain of the input signal, the voltage at the output, and the power dissipation of the output devices. The more output devices there are (tubes or transistors) means the more power can be dissipated without them burning up. So if you want a tube amp that can deliver 40, 50 or a 100 watts of power, you need more tubes. And more tubes means more parts and labor and that drives up the cost. |
what about preamps specifically? except for heat, the more the merrier? mine is a tube tuner/preamp, 17 tubes in all http://www.mcintoshcompendium.com/Compendium%20Docs/Tuner%20-%20Pre-Amps/PDFs/MX110LATE.pdf |
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Not sure what is meant by 'direct path'... But if you need a lot of power, you might need a lot of tubes to make that power. If so, they'll be in parallel, which means the signal is fed to all of them and they all work in tandem to make that power. In that particular case, the signal path complexity is the same whether one power tube is used or 20. But… the signal is added up coherently, whereas the noise is adds non coherently. So in theory it is better to have the elements in parallel. |
Atmasphere nailed one good reason (duh). There are quite a few others, from using tubes to rectify, regulate, as differential amplifiers....none of which greatly complicate the signal path. Plus several gain stages, each very linear, are sometimes better than one gain, over stressed stage. And a million more answers that really benefit from a fairly extensive understanding of electrical engineering.... |
You need to use a lot of power tubes if you want crank up the output without putting a really heavy burden on each tube. So that's why you see the 100w tube amps often use an octet for example. Not my cup at all as I prefer lower output triode amp paired with high efficiency/easy load to drive speakers. But the technical explanation is simple...to the point this does feel like a trolling thread. |
I don't use high power (Lamm ML2 SETs in the main system) but everything from phono stage and power supply to line stage to amps is tube circuitry so I do use a lot of tubes. That in itself is not a problem. (I like to think of them as "field replaceable" parts that solve some, not all, problems). The difficulty is finding good sounding tubes that satisfy--and in that, I don't mean to be a snob-- to the contrary, a modern circuit that can work at optimal level with current production tubes would be preferable to having to hunt for increasingly scarce, and expensive, NOS that is fresh. With tube gear, I've had pretty good luck since the early '70s with medium powered amps (70 watts or less) and minimal issues with tube preamps. My current amp set up is the above Lamms-- pretty simple and lower powered at 18 watts per amp-- or in current operation, some restored Quad IIs running real GEC KT 66s. I haven't counted how many tubes are in circuit in either system, but it's probably a lot. I replace/refresh when necessary. It's part of the routine operating cost of tube gear, with the above caveat about sonics and NOS/scarcity and cost. |
For non output tubes sometimes a gain tube is followed by a cathode follower which is sort of an electronic transformer to lower the output impedance of a gain tube so it drives the next gain tube better. Goof examples are 1970s and 1980s Audio research amps and preamps.. This effectively can double the small tube count. Another possiblity(which can be also combined with cathode followers) is push/pull voltage gain stages. This doubles the number of small tubes also. Again look at the Audio Research products from the 70s and 80s. Push/pull needn't be used for voltage gain even with push/pull output amps. And many preamps are single ended too even from manufacturers who made push/pull tube output amps. |
Not a troll thread at all. Seems like a complicated way to reproduce music. And yes a little bit of laziness involved, but electrical engineers make lousy writers as the subject is a difficult exposition. So some of tubes are the same as the power transformers? And I am open to SS to being more complicated. |
Respectfully, the idea that the number of cylinders in an automobile has a relationship to horsepower is NOT a good analogy... Let's consider a modern V-12 power plant say from a Bentley or Aston Martin. Now, let's compare that to a V-8 funny car or top fuel dragster. Or an F-1 motor. Ridiculous comparison, yes? Of course, you need to take into account displacement, air/fuel delivery, torque delivered, etc. which are VERY different in the above examples... however the number of cylinders has little to do with ultimate power output but does have to do with HOW that power is delivered... Happy listening. |
@musicfan 2349, No it’s a totally valid comparison. You can take 12 el34s and run them conservatively or you can take 8 kt150s and run them hard in dual mono set up. A V12 top fuel drag car (if they existed) will walk away from the V8 top fuel drag car. There’s no replacement for displacement...remember? You’re being a bit nitpicky with you’re point...but I think you know the general sentiment. |
Seems like a complicated way to reproduce music. And yes a little bit of laziness involved, but electrical engineers make lousy writers as the subject is a difficult exposition.From this I get that tubes are complicated and transistors are moreso. That's correct. The alternative is no music. That makes me crazy and then it gets complicated :) |
A V12 top fuel drag car (if they existed) will walk away from the V8 top fuel drag car. There’s no replacement for displacement...remember? False. Cylinder count and displacement are not mutually exclusive. You can have a 4 liter 12 cylinder Ferrari and a 4 liter 6 cylinder. Exact same displacement. Depends on the designers goals and the desired torque and horsepower band and at what RPM. There is a reason you wont find a 12 cylinder top fuel dragster and it isnt because they cant figure it out. |
There's a 50cc class of racing motorbikes. Back in the 50s and 60s it became all about how many cylinders you could get to displace only 50cc. Things got real small and because things really didn't weigh all that much revs were over 20,000! So they put a stop to it and 50cc is now limited to one cylinder. In the audio world this would be akin to using a lot of really small tubes to make an amp but it would be a really poor analogy. |
@ghasley Yeah, you gearheads are too deep in the weeds on this. The point...the general point...is that you can run a bunch of small tubes softly (small piston v-12 jaguar) vs fewer big tubes (big block American V8) run really hard. " Depends on the designers goals". Do you get it now? It’s the general idea as an analogy. It’s just a valid comparison...not the exact same thing. |
Seems like a complicated way to reproduce musicYes, it is. It’s taking sound vibrations, storing it on a physical media, then retrieving the signal, modifying and amplifying the signal as needed to drive transducers in speakers. It’s an imperfect process, a facsimile of reality, but that’s all we got for now. Then you have high end audio which emphasizes quality sonics which often means: lowering the noise floor, minimizing EMF and RFI interference, cleaning the AC power, minimizing distortion, shortening the signal paths, minimizing internal vibrations, controlling case vibrations, designing better circuits, using higher quality/specification parts, using cutting edge materials and techniques,...etc. |
There's a 50cc class of racing motorbikes. Back in the 50s and 60s it became all about how many cylinders you could get to displace only 50cc. Things got real small and because things really didn't weigh all that much revs were over 20,000! So they put a stop to it and 50cc is now limited to one cylinder. Yeah but Ralph you are Da Man with stuff like this so I have to ask, what about going the other way? Why not use one great big high power tube? The reason I ask is some guys I respect are going that way with SET and real happy with it. Of course everything else still matters too but might there some inherent advantage to using fewer tubes? |
@jpwarren58 Not a troll thread at all. Seems like a complicated way to reproduce music.please enlighten us, what would be a simpler way? So some of tubes are the same as the power transformers? https://splice.com/blog/vacuum-tubes-in-music/ https://www.electronics-tutorials.ws/transformer/audio-transformer.html https://en.wikipedia.org/wiki/Valve_audio_amplifier https://www.youtube.com/watch?v=Aj3LNHqUt3A https://www.rs-online.com/designspark/building-a-valve-amplifier-part-1-design-components-and-layout as you posted the original query, hope you have the patience to absorb the info above for some basic knowledge on the subject |
Yeah but Ralph you are Da Man with stuff like this so I have to ask, what about going the other way? Why not use one great big high power tube? The reason I ask is some guys I respect are going that way with SET and real happy with it. Of course everything else still matters too but might there some inherent advantage to using fewer tubes?Not really (if we're just talking about power tubes). All tubes are imperfect. So you run with one tube you deal with its imperfections. When you parallel a great number of them the differences tend to iron out and act more like the tube is supposed to in the data books. But you have a lot more current capacity so more power- without a distortion downside as long as the driver circuit can handle the grid capacitance of so many tubes. And that's not really a problem- we've been doing that for decades. To give you an idea of how different the distortion figure can be, almost any SET when driven to clipping will make about 10% distortion (for this reason a good number of SET manufacturers spec the power at the 1% or 2% power level. rather than clipping). By comparison as an example, our M-60 makes between 0.5% to 1% THD at full power, but that power is 60 watts, compared to an amp that might be making only 8 watts. You can see that if the M-60 is then operated at the same power levels as the SET that its distortion will be much lower- probably 2 or 3 orders of magnitude lower (since both amps are zero feedback and their distortion decreases to unmeasurable as the power is decreased). Distortion obscures detail, and it adds coloration since the ear interprets all forms of distortion as some sort of tonality. So even if the amp has a good distortion signature (which will cause it to sound smooth and not harsh) it simply will be unable to express detail in the way that an amp with the same but much lower distortion signature can. So while the guys you know might be quite happy, that isn't the same as hearing everything out of their recordings that they could. One power tube is fun, it has a nice gothic steam punk appeal and SETs have a good distortion signature even though its quite high. But you can do better. |
@invalid “The only problem I have with all this detail is you don't hear it like that in a live environment “ I think it is a question of emphasis. All the details are there in the live environment, but typically they don’t stand out as much as the tend to on some systems. My experience is that tube systems frequently get the emphasis right. Solid state tends to spotlight the details. |
The number of tubes increased as speaker efficiency decreased. Paralleling tubes or going push pull can increase power but also can muddy the sound. As a builder of SET amps I focus on using as few tubes as possible. Each tube has its own sound due to its harmonic signature. To many harmonic signatures can lead to a softer or muddy sound. A well set up SET can be as detailed solid state amp. With the addition of a level of harmonics that keep it from becoming sterile. But you are back to using efficient tubes. As to using a giant 50 or more watt transmitting tube. They are hard to power their heaters. |
