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It's all psychology

4/21/2003 5:51 PM
stephen conner	It's all psychology What if you were playing a SS amp and thought it was a tube amp? Or vice versa? I think a lot of the trouble comes from peoples' fixed ideas, namely that tubes somehow have some magical mojo that transistors don't. If we were to discard this idea we would be free to see the truth, which is that there are some good-sounding SS amps, and some crap-sounding tube ones. Steve C.

4/21/2003 5:51 PM

stephen conner

It's all psychology

What if you were playing a SS amp and thought it was a tube amp? Or vice versa? I think a lot of the trouble comes from peoples' fixed ideas, namely that tubes somehow have some magical mojo that transistors don't. If we were to discard this idea we would be free to see the truth, which is that there are some good-sounding SS amps, and some crap-sounding tube ones.

Steve C.

4/21/2003 7:54 PM

r.g.

Re: Interesting theoretical question

quote:
"imo, it always comes down to the grace under overload conditions."

Very good point indeed. You can't just build bigger and bigger amps until they won't ever clip. People will just keep turning them up until they do. So you have to make some explicit kind of limiting happen.

There is some precedence. The old Thomas Vox amps used an adjustable limiter in front of the power amp. It turns out that it was stuck in there explicitly to make the power amp clip in a specific way. The thing is supposed to be adjusted so that the limiter clips the signal, not the power amp running out of voltage headroom. It's only there in the "big head" models, not the smaller amps. And the horns in the speaker cabs make them sound harsh. But if you diable the horns, the Beatle actually sounds pretty good for a SS amp. I think it's because of the limiter.

quote:
"another thing i am acutely aware of is the presence of microphonics in tube circuits. not too many ss circuits that are discernably microphonic, yet ALL tube circuits are to a greater or lesser extent! i think the micros add a great deal of ambience and air to the outcome. again, this is preferably in the sound GENERATION stage, not reproduction. "

Ah. Another good one. Really valid. That comes through as a welter of frequency varying delay loops fed back into the signal stream. mmmm.... I have to think about that one. The obvious is to install a number of small mike capsules, but that seems a bit technically backward. A many, many tapped short delay line for feedback?

I bet the DSP modellers don't do that, and they should. It's a natural.

On another note, ceramic caps are furiously microphonic in any low level amp.

R.G.

4/22/2003 7:48 AM
Glenn	Hey kg, microphonics... The thought that just crossed my mind, and I'm sure someone has made this point at one time or another, but I think some degree of microphonics may be the 'X' factor that some people prefer. Perhaps it is the sympathetics of a microphonic effect that makes the tubes seem more 'organic' or pleasing with all else being presumably equal. At the heart of their operation, Musical Instruments resonate and do so a certain way and that is how we distinquish different timbres, and find a preference for different timbres as well. So to with outboard gear, perhaps... Everyone's biology, psychology, and environment is different and this effects their preferences. Hey! How about a quasi-scientific survey amongst us all here about our favorite reed instrument and then favorite amplifier preference. Perhaps there may be a correlation there, or some other timber-preference so that some conclusions may be drawn? I'm a little loopy, so forgive me if it doesn't jibe too well... Glenn

4/22/2003 7:48 AM

Glenn

Hey kg, microphonics...

The thought that just crossed my mind, and I'm sure someone has made this point at one time or another, but I think some degree of microphonics may be the 'X' factor that some people prefer. Perhaps it is the sympathetics of a microphonic effect that makes the tubes seem more 'organic' or pleasing with all else being presumably equal. At the heart of their operation, Musical Instruments resonate and do so a certain way and that is how we distinquish different timbres, and find a preference for different timbres as well. So to with outboard gear, perhaps... Everyone's biology, psychology, and environment is different and this effects their preferences.

Hey! How about a quasi-scientific survey amongst us all here about our favorite reed instrument and then favorite amplifier preference. Perhaps there may be a correlation there, or some other timber-preference so that some conclusions may be drawn? I'm a little loopy, so forgive me if it doesn't jibe too well...
Glenn

4/22/2003 1:15 PM
KB	Glen, that's a whole new thread and one I was going to bring up later as I've been studying Timbre and how to change it in an amp. Surely effects will do it but I was thinking naturally with harmonics. I mean look at EJ with his Violin tone. Well Larry Carlton IMO has a flute tone so why not a sax,trumpet,oboe, or whatever. It all has to do with harmonics and sesory dissonance as a relationship to a frequency ratio. Can it be done without effects by controlling the harmonics with tubes. Maybe output tubes as they have singing qualities but I think it would be hard with preamp tubes but hey that's where the voicing is so it has to play a part., KB

4/22/2003 1:15 PM

Glen, that's a whole new thread and one I was going to bring up later as I've been studying Timbre and how to change it in an amp. Surely effects will do it but I was thinking naturally with harmonics. I mean look at EJ with his Violin tone. Well Larry Carlton IMO has a flute tone so why not a sax,trumpet,oboe, or whatever. It all has to do with harmonics and sesory dissonance as a relationship to a frequency ratio. Can it be done without effects by controlling the harmonics with tubes. Maybe output tubes as they have singing qualities but I think it would be hard with preamp tubes but hey that's where the voicing is so it has to play a part.,

KB

4/22/2003 7:21 PM

steveR

further tangents

quote:
"There are a lot of people who can tell the difference between a tube amp and a solid state amp by listening to the amps live, right? "

I think when it comes to very low gain or super high gain the differences are actually pretty negligible. It's the area where the amp goes from clean to dirty with the player's dynamics where I find the difference is.

In higher distortion scenarios I think people can tell when a tube amp is working really hard. Maybe something about the combined effect of the clipping characteristics of different stages contributes to that distinctly "tube" tone.

quote:
"- if we can still tell, would solid state power amps work for some other way to make that same analog signal going into them? "

Isn't this essentially what the Line6 amps are? The have the modelling preamp sections (derived from software DSP plugins) run into a SS power amp. The modeling stuff sounds pretty good up to a point. (They demo nice in the store!) But once cranked up they still lose something.

The further challenge...can anyone detect a RECORDING made using tube equipment?

4/23/2003 1:46 AM
dpcoyle	Re: Hearing tubes IMO, you have to distinguish between sound production and sound reproduction. Production: the transfer function of tubes, compared to transistor's, is simpler. A device with a higher order distortion residue, a transistor, can't emulate a simpler device, any more than a kazoo can sound like a flute. (Fourier says enough flutes can sound like a kazoo, though.) As KG said, the tube sound is real obvious in overload, but IME they are obvious at all levels. Consider that tubes vary in their gain within one cycle. They are in a complex matrix, a 50 element tube amp. The Catholics distinguish between sins of omission and sins of commision. It is just as bad to let a man drown by not throwing him a life jacket as to push him over the transom, but it may not be as obvious. Transistors and tubes both have inaccuracies of response in the time and amplitude domain, but the ear is less sensitive to some errors, naturally, like 2nd order distortion. And some people like the tizz of SS. But many folks react negatively to transistor amps over time, possibly due to odd order distortions that are added. The tube's sins of ommission are less noticeable, so accepted by the ear as parts of the spectrum missing, rather than spuriae added, which triggers our unease, because there is something going on that we have not accounted for. Can you hear a tube amp distortion reproduced through a transistor amp? Hell yes. Can you tell a signal has gone through a transistor? Only if you are sensitive to transistor distortion. What makes the essence of a tube amp and what can be left out? I think this board has spent 4 years detailing the notion that almost every little thing has a contribution. You can't make it sound like a Deluxe without all the bits. Re reproduction, Krell and Threshold (RIP),and others prove that you can make a transistor amps can have so few sins as to sound great, and what bass, but compare a $1000. tube hifi amp to a $1000 transistor amp, and things are pretty obvious to a lot of folks. There is no magic, it is all physics, it is just not yet articulated, as I see it. Dan

4/23/2003 1:46 AM

dpcoyle

Re: Hearing tubes

IMO, you have to distinguish between sound production and sound reproduction.

Production: the transfer function of tubes, compared to transistor's, is simpler. A device with a higher order distortion residue, a transistor, can't emulate a simpler device, any more than a kazoo can sound like a flute. (Fourier says enough flutes can sound like a kazoo, though.)

As KG said, the tube sound is real obvious in overload, but IME they are obvious at all levels. Consider that tubes vary in their gain within one cycle. They are in a complex matrix, a 50 element tube amp.

The Catholics distinguish between sins of omission and sins of commision. It is just as bad to let a man drown by not throwing him a life jacket as to push him over the transom, but it may not be as obvious.

Transistors and tubes both have inaccuracies of response in the time and amplitude domain, but the ear is less sensitive to some errors, naturally, like 2nd order distortion. And some people like the tizz of SS. But many folks react negatively to transistor amps over time, possibly due to odd order distortions that are added. The tube's sins of ommission are less noticeable, so accepted by the ear as parts of the spectrum missing, rather than spuriae added, which triggers our unease, because there is something going on that we have not accounted for.

Can you hear a tube amp distortion reproduced through a transistor amp? Hell yes. Can you tell a signal has gone through a transistor? Only if you are sensitive to transistor distortion.

What makes the essence of a tube amp and what can be left out? I think this board has spent 4 years detailing the notion that almost every little thing has a contribution. You can't make it sound like a Deluxe without all the bits.

Re reproduction, Krell and Threshold (RIP),and others prove that you can make a transistor amps can have so few sins as to sound great, and what bass, but compare a $1000. tube hifi amp to a $1000 transistor amp, and things are pretty obvious to a lot of folks.

There is no magic, it is all physics, it is just not yet articulated, as I see it.

Dan

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