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Tubes vs Transistors: An Audible Difference?
cgenman writes "Are those vaccuum tubes worth the extra price? This paper, a transcript of a speech to the Audio Engineering Society of New York, indicates so, though the reason is surprising: Overloaded tubes behave better.
While the speech itself is from the early 70's, the paper takes on new importance with the recent trend in louder is better music."
If part of being better includes consistanly sounding the same, then glass audiophiles have to tuck their tales between their legs. Tubes wear out. As they wear out, their sound qualities change. Who's to say that the 'changed' sound is desireable? Maybe it's an improvement...that's the problem; it's not cosistent.
Regardless of which one you feel is more accurate in its source reproduction, solid state devices have the advantage in that they pretty much (not 100%) maintain whatever sound characteristic they start with.
Tube amps are considered more of a "status" item these days... When someone tells you they just got a nice new $300 tube amp, you kind of want to check it out, because it sounds cool...
from a 1970's vintage copy of Popular Electronics. When the inputs are overloaded, transistors will clip the input signal with a very sharp transition. Tubes will transition out of the linear state more gradually. A clipped sine wave coming out of a tube amplifer will have rounded edges. This reduces the number and amplitude of high order harmonics present in the clipped output.
That being said, the obvious answer is not to overload the amplifier inputs. But if you really, really like the effect of an overloaded tube amplifer it is easy enough to simulate with a little filtering. (Analog or digital)
If you really want that old "vaccum tube" feel to the sound, try injecting just a touch of 60 or 120 Hz hum into the output.
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I once met a guy who was a licensed electrician. He had installed a stereo system is his car. I don't know what the specs were or even what kind of car it was, the thing that stuck in my mind about it was how nice the stereo sounded. Moreover, when he turned it all the way up it didn't distort or hurt my ears, in fact, though it was impractical to carry on a conversation, I didn't come away feeling like I had just stepped off the tarmac at the local airport. Anyway, when I commented about how loud it got, he replied, "I didn't build it to be loud; I built it to sound good." Anyway, that kind of squashed the whole louder is better argument for me.
I think it's funny how something I post completely off-the-cuff because I'm in a cynical mood today more than I felt I had any insight into the history of volume in music, and I get modded up insightful twice. But on other occassions, I make truly thought-out posts and get modded down for flamebaiting. I know Slashdot is structured against a dictatorship, but it really feels like I'm always being moderated by a single retarded asshole every time.
It seems like you have listened to the 1970s-era solid-state proponents a bit too much. The "nice sounding distortion" myth is just that.
The issue brought up in the article is no longer a concern. There are transistor amplifiers with soft clipping, and clipping shouldn't happen in normal situations anyway.
However, high-quality tube amplifiers have one characteristic that class B transistor amplifiers do not: zero negative feedback. Transistor amplifiers need large amounts of negative feedback to obtain low distortion. Tubes don't need it. That means you have virtually no high-order distortion harmonics in a tube amplifier, while transistor amplifier distortion is mostly high-order.
It has been shown that high-order harmonics sound very nasty, even in tiny amounts. It has also been shown that the human ear produces its own low-order distortion, so low-order harmonics do not sound objectionable to us. Now put two and two together. Tube amplifiers may not have very good distortion numbers, but the type of distortion they produce is not as objectionable to a human. It's not that 2nd harmonic distortion sounds good -- it doesn't. It just doesn't sound as bad.
>Just try to design 3kW hifi audio amp and see what will be cheaper...
You have a source for tubes than can handle (assuming we are hooking up some magically-able-to-handle-3kw-home-speaker) 20 amps of current? If so, show me the money. Otherwise, you know the old saying, shut up or put up.
I say this because I am certain I can find transistors that can do that.
Now, since I can't find ANYTHING in a tube amp that can handle 3kw (examples, please), I'll post this example, a 200 watt tube amp running at (*GASP*) $6000!
To show I'm not making those numbers up, here's another (now discontinued) tube amplifier, weighing in at a "hefty" 60 watts RMS (my 30 year old H/K 430 solid state amp beats it! LOL!). MSRP: $1,995.
Now, assuming the usual laws of economics apply, I will again, assume, that a 3kw tube amplifier will cost much more.
I can assure you a 3kw RMS solid state amplifier will cost under $6000. In fact, it'll cost you $1,129. If you bitch you don't like the brand name, I can find others in the same price range. And you'll look silly bitching about it, too, because Peavy definately isn't Yorx quality.
But please, please, do tell me where I can get get a 3000 watt tube amp for that price or lower. I'd love to buy, oh, say, 10,000,000 of them. I'd be richer than Bill Gates when I sell them for, oh, about 1000x the price without a hitch.
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~jeff
"Almost every high end audiophile system includes a set of power tubes specifically because audiophiles _know_ that tubes sound best. DSP simply cannot reproduce the warm tones of tubes."
:)
Similarly, synth manufacturers have started putting tubes into their products - for example, the recently released Korg Triton Extreme uses tubes to process the sounds. Considering this has an extremely powerful DSP engine, it's doubtful the effect could be used digitally.
That said, some manufacturers tend to use tubes as a "this makes our product instantly better" feature...not always true
I can not site a specific year and month but back in the early eighties, Stereo Review did extensive blind A/B tests using different speakers and db levels. In one test, almost ~90% of the participants picked a certain test to sound the better then another one. That test was the same exact pair of speakers but played an average of only 1db louder. The hard part is actually picking a better sounding speaker as a cheap piece of crap with a higher efficiency will fool most people. Take a very common case like subwoofers for example. IMHO, a sealed enclosure system sonically beats a typical ported box setup in just about every aspect except for one, output level at a narrow frequency range that the speakers port is tuned too. Ask a group of people which sub woofer "sounds" better and almost every one of them will select the almost monotone thumpy but louder ported box.
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So yes, there are tubes which can handle extremely large (nigh-insane) loads. The tubes might be big, bulky, and made of ceramic, but they exist.
I wholeheartedly agree with the article discussing the Rush album; those waves *were* severly clipped, and whoever mastered that CD should be very very ashamed of themselves (although it looks like the clipping happened in several stages, not just in the final mastering) for forgetting what matters the most in audio production: Quality control of the product by using their ears. Californication of the Red Hot ChiliPeppers lacked the same final check, it's horribly clipped as well.
HOWEVER, As someone with (some) experience in audio production, I should mention that when a signal is compressed and then amplified, this can help increase the detail in weak signals. This is nothing new; in old vinyl recordings, especially of classical orchestras (music with a lot of dynamics) the sound engineer had no choice but to apply some compression to the result.
For digital audio, it is easy to maximize audio levels with any wave editor: Almost every one of them has a "normalize to maximum" function. No harm in that; it allows to maximize the level without clipping it. Typically, gives a result with average sound level of 3-6 dB below 'professional' CDs which is so common to find in 'amateur' demos. The best way to punch up the volume further is by turning it up on the amplifier. However I found my customers wanted the CD itself to be louder. Here's how I did it without causing any clipping.
By itself there is no problem of punching up the level another 3-6 dB, but if you're going to do this by simply increasing the amplitude, the signal *will* clip and sound horrible. Instead, apply a very light distortion over the signal (in cooledit 96 it used to be under the Special menu, draw a slightly bent curve, amplifying softer signals a bit more than the louder ones), essentially mimicking what a tube does. This will increase the average level of the signal, increase perceived definition of the signal, but will not cause clipping. It will color the signal, but in a pleasant way, just like tubes.
This technique does however have two downsides: 1. Because it does color the signal, it may mess up with your carefully balanced mix and equalization. 2. when used to excess, it may still cause unwanted distortion sound. Use your ears to proof the final result. As with all audio matters, don't go for bullshit. Most importantly, let your ears be the judge. And did I mention to use you ears to judge the final result?
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Of course not, but they do contain extremely-hard-to-model non-linear responses of a bewildering variety of kinds. If they didn't, then no one would pay $500+ for DSP emulators like Native Instruments' recently released Guitar Rig, and everyone would just code their own in csound or Max/MSP.
In other words, the software market shows that it takes quite a lot to mimic the sound of classic tube amps (and speaker cabinets, etc.). So, when someone (who actually uses these things on a daily basis, for example) says that tube amps can't be matched by software, they're not necessarily saying there are magical fairies in their tubes (though some meatheaded guitarists might say that), they could be reflecting a knowledgeable point of view on the reality of the current situation.
Personally, since I use these things a lot (I do a lot of home recording) and have seen how they've progressed, I have no doubt that software will eventually match classic tube amp sounds for guitar; it may not even be that far in the future. But it ain't here now.
Shop as usual. And avoid panic buying.
Oddly enough, some seem to think that bipolar transistors sound better than MOSFETs. Go figure.
This whole tubes vs. transistors thing reminds me of some other debates over the years. Moving magnet vs. moving coil phono cartridges. Direct-to-disc vs. tape mastering. Linear tracking vs. radial tracking tone arms. And of course, analog vs. digital.
All much ado about nothing, IMHO. Each with a small but vocal cadre of fanatics extolling the virtues of their favored "underdog" technology. Usually that was whichever one was older, or more costly, or percieved as more exotic. Whether it was actually better was largely a matter of personal taste, and was rarely supported, and sometimes even contradicted, by any kind of objective tests.
The tube nuts need to come to grips with the fact that just because they prefer the sound of tubes doesn't mean that everyone else will prefer it too. That it's different is something we can establish objectively. That it's better is entirely subjective. Use whatever you like. It's no skin off of my back.
BTW, back in my vinyl days I had a moderately high end (350 1982 dollars) electret phono cartridge. That's a technology that was rarely taken seriously by those on either side of the MM/MC debate because it was generally associated with very cheap low-end equipment. But just as is true with both tube and solid state amps, a well designed and well built implementation can yield excellent results.
My old ~1987 Proton D940 uses magnetic amplifiers. The little reciever/amp clocks in at around 40lbs. Sounds better than almost everything available today.
I wonder why this technology quietly died.
Get a free ipod.
I used to believe this. I said, "Heck, there's two amps and they both have 0.01% distortion or less at reasonable volume levels, so who could ever tell the difference?" Well, when I upgraded my home stereo from a relatively cheap mass-market amp to a $2500 or so higher-end (but actually lower-power) amp I was astounded. It sounded ilke there was another octave of bass - all of a sudden, bass guitar sounded like the real thing. Kick drums had *kick*. And not just the bass end got better: the net result was nicely balanced, really clean, enjoyable sound (sorry I don't know any fancier audiophile jargon to describe this ;-)). I don't know the technical reason for this. Maybe it's the nasty reactive load a speaker presents to the amp that makes amps that theoretically are the same sound different. But I'm a believer now. (No, neither of the amps I'm talking about are tubed. There are good tube amps *and* good transistor amps on the market now).
Anyone remember this thing? I never heard anything else about it besides a little picture and comment in Maximum PC Magazine nearly 2 years ago. Are tube preamp boards still in production?
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... and CD's made more than a decade ago, the old stuff wasn't mastered with all the hypercompression and clipping that almost all modern pop CD's have to have to be contenders in the "VOLUME WARS."
You can make both tubes and transistors sound clean or dirty (distorted), and they do sound quite different when dirty and each is "appropriate" in different contexts, but having whole albums sounding dirty causes ear fatigue and it just sucks.
Does anyone else find it ironic that LP's were recorded with a substantially greater dynamic range than is used on current CD's?
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Maybe you should have highlighted this part of your post so I will for you: "the big stumbling block is this: you gotta know what transfer function you want to emulate first." Currently, the biggest difference between transistors and tubes is in the "texture" of the sound. Tubes tend to be more "immediate" sounding in the midrange. This isn't a frequency thing, it's not easy to place exactly what it is. The DSP guys have already figured out the distortion and frequency aspects of tubes but they haven't even begun to touch the tactile qualities of them. When someone figures out why tubes act this way, or even a way to reliably describe the effect then maybe we can get those great DSPs to emulate it. As for now, it's about as simple as tubes have it, transistors don't.
There is a very simple reason why tube are said to sound better. When a tube overloads, it induces 3rd harmonic distortion (odd order) whereas transistors output 2nd harmonic distortion.
The later is harsher on the ear, more edgy. The reason is that when a transistor overloads it actually "cut" the peak of each wave cycle overloading, effectively transforming the round wave into a square wave. Tube distortion is said to be warm because it's steady and fuzzy, when it distort it "squashes" the peak of each cycle oveloading instead of "cutting" it. Tube also have a better headroom than transistors (amount, in dB, a signal can overload before the distortion is actually perceivable).
Transistor are more clinical, which isn't bad at all and is something you'll often want, actually in recording mics and preamps and about anything are more like brushes to an artist than simple tools. Each piece of gear has its sound, each sound has its place. tubes aren't better than transistors, they're just different. When each of them starts to misbehave the tube is gentler though.
Don't take this the wrong way-- I'm a practical bang-for-your-buck sort of guy. But don't confuse tube amps used for audio replication (like in your home stereo) with those used for performance (like in a guitar amp). In the latter case, the tubes and the amp are themselves part of the instrument, and part of making that sound what it is-- feedback, distortion and all.
That said, after that lovely guitar/tube amp sound is recorded somewhere, I'll be playing it back on a nice transistor rig at my house. Because at THAT point, all I want is accuracy. Affordable accuracy, as I use it to cleanly reproduce distortion somebody else made.
Two separate things: amplifier as instrument, and amplifier as sound playback device.
i bought a marantz 1030. 2004, i use the same unit to run sound from my emu10k1. it still sounds nice. it powers two homemade speaker enclosed dual coned automotive walmart on sale i forget who made em speakers. the 1030 is prone to intercept cb radio transmissions, and that gets annoying as i live nearby a heavily travelled truck route. it's only 13 watts RMS, but itsa quality 13 watts. it's as close to a tube amp as i'm gonna ever get.
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Oh you'd be able to feel it for sure, lol. But I know for a fact the number is 140, I'm just not sure what happens when you go over that, is it kinda like an organic clip maybe? Or does it just garble and not even register as sound? I don't know...
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I was able to hear the 16K but it sounded 'lower' than the 10K and 20K. 20K less audible than 10K
Never trust your speakers. Get a sound pressure meter. Take it's output and check the THD. You may find the sound at 45 DB sounds quiter than the one at 67 DB. Many home stereo speakers have more than 15 DB changes when swept from 200 HZ to 5 KHZ. Only the very best speakers hold the level within 10 DB from 100 HZ - 20 KHZ. Most home stereo speakers won't give the response curves in their technical data. They are a much bigger influance over sound quality than most stereo amplifiers. That's why I spent more time and money on my selection of speakers than I did on the amplifier. It's not hard to find an amp that puts out a response of 20 HZ - 20 KHZ Plus or minus 3 DB with less than 0.01 THD. Finding speakers that put out 60 HZ - 15 KHZ plus or minus 10 DB is a little harder. Finding one that puts out less than 0.01 THD is even harder.
The discussion may need to be on speakers next time instead of amplifiers.
I went to the CES a few years ago. I went to a room with a grand piano solo playing. The pianist got up and greeted me. The music didn't stop. It was that real. Most stereo speakers sound like a piano playing over a stereo, not like a grand piano playing. A good amplifier by itself won't create the illusion of a real piano. Get good speakers.
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