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post #1 of 20 (permalink) Old 02-09-2004, 06:58 PM Thread Starter
 
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Question about tubes

I just had a thought today, U know how tubes are just switches right? Why cant ppl just use transistors instead of em? I was thinking that the first computers used to use tubes to perform calculations, by turing either on or off, and then the transistor microchip came out which was smaller and did the same thing, so why didnt the guitar amp go the same way? Wouldnt transistors be a more reliable form of changing the current?
Oh and one more question; how come a tube e.g a switch can change/ colour the sound so much if all its doing is turning on or off? Could this effect be studied and simulated using some sort of circuitry? Sorry if im completely off the mark on this stuff as I am new to the world of tubes, and have alot of unanswer'd questions.
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post #2 of 20 (permalink) Old 02-09-2004, 07:11 PM
 
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the effect can be simulated, by digital modelling. They might not sound quite right just yet, but they will be able to reproduce the right tone exactly in a few years (if that). If anyone doubts this, this same situation came up with the advent of cd's. People thought they they sounded "sterile" and "lifeless" but when taking a double blind test (in comparison to vinyl records) people couldn't tell the difference.

CD's are a superiour medium to vinyl, and so will digital be to tubes. Tube "snobs" will hang to tubes just like people did with vinyl.
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post #3 of 20 (permalink) Old 02-09-2004, 07:47 PM
 
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Except for the fact that one cannot attain:

A crisp, clear transistor overdrive. Theres just no such thing. Overdrive is where the tubes are simply distorting the signal they are running so hard.

Also, when running a tube (valve) amp, one can control the distortion via the guitars volume control. Try doing that with a transistor amp.

Tranny amps tend to give better clean sounds. Tube qamps tend to give better crunch/high gain sounds. its as simple as that IMO
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post #4 of 20 (permalink) Old 02-09-2004, 08:57 PM
 
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Quote:
Originally Posted by Kev Brigden
Except for the fact that one cannot attain:

A crisp, clear transistor overdrive. Theres just no such thing. Overdrive is where the tubes are simply distorting the signal they are running so hard.

Also, when running a tube (valve) amp, one can control the distortion via the guitars volume control. Try doing that with a transistor amp.

Tranny amps tend to give better clean sounds. Tube qamps tend to give better crunch/high gain sounds. its as simple as that IMO
YET. There are parameters that are just not being addressed yet. Just like the early CDs had linearity errors, tons of jitter, bad (or no) dither, etc. But NOW, 16 bit CDs can rock, let alone 24/96 digital.

As it was with CDs, so shall it be with tubes. And good riddance to them, for the same reasons - touchy, finicky, expensive, inconvenient durn thangs!
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post #5 of 20 (permalink) Old 02-09-2004, 09:05 PM
 
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Both tubes and transistors both have applications as switches, ie, either full on, or full off to put it simply.

In an amp, the signal is fed into an amplification stage. As no stages produce an exact replica of the signal (due to device characteristics and nonlinearity of devices) there is always some "colouring" of the sound.

The reason why tube amps weren't superceded by transistor amps is that to the majoriy of guitarists tubes sound more musical when pushed than transistors. it's nothing to do with technological advancement. Transistors can be made extremely small, thus aiding high speed switching (ie, microchips), whereas a valve will always be a lumbering large chucnk of glass that operates at hign voltage and on the principle that electrons are attracted to or repelled between two plates at a visible dsistance in a vacuum, thus making them slow at switching.

Hope that clarifies something
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post #6 of 20 (permalink) Old 02-09-2004, 09:07 PM
 
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Quote:
Originally Posted by JESTER700
Quote:
Originally Posted by Kev Brigden
Except for the fact that one cannot attain:

A crisp, clear transistor overdrive. Theres just no such thing. Overdrive is where the tubes are simply distorting the signal they are running so hard.

Also, when running a tube (valve) amp, one can control the distortion via the guitars volume control. Try doing that with a transistor amp.

Tranny amps tend to give better clean sounds. Tube qamps tend to give better crunch/high gain sounds. its as simple as that IMO
YET. There are parameters that are just not being addressed yet. Just like the early CDs had linearity errors, tons of jitter, bed (or no) dither, etc. But NOW, 16 bit CDs can rock, let alone 24/96 digital.

As it was with CDs, so shall it be with tubes. And good riddance to them, for the same reasons - touchy, finicky, expensive, inconvenient durn thangs!
If it were only that simple... Transistor amps may give a better reproduction of a clean signal, mainly because transistor amps are morelinear, unfortunately, when overdriven they tend to produce harmonic content that isn't as pleasing to the ear as valves.
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post #7 of 20 (permalink) Old 02-09-2004, 09:29 PM
 
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me and jester weren't so much saying that transistors will be the end of tubes, but digital amps will.

The advantage of digital is the ability to do just about anything.

Guitar amps can be simplfied to this. A signal goes into the amp, then a signal goes to the speaker. With digital processors, the signal that is sent to the speaker can be replicated. Right now, we can't get it exactly right, but we will be able to get it exactly right.
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post #8 of 20 (permalink) Old 02-09-2004, 10:17 PM
 
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Quote:
Originally Posted by The Madness Here
me and jester weren't so much saying that transistors will be the end of tubes, but digital amps will.

The advantage of digital is the ability to do just about anything.

Guitar amps can be simplfied to this. A signal goes into the amp, then a signal goes to the speaker. With digital processors, the signal that is sent to the speaker can be replicated. Right now, we can't get it exactly right, but we will be able to get it exactly right.
Yup. Just a matter of time. But even after the time when it actually happens, there will be those who prefer the "pastiche" of tubes and deny that they have truly been supplanted. Just as there are still vinyl fans. Note that I don't take issues with those who say vinyl "sounds better"; that's a taste call, and if you LIKE that kind of distortion, more power to ya, sez I. But they who claim it's "more accurate" need to study & listen some more. No names *cough* neil young *cough*.

But there is one device where, IMO transistors have come damn close - the SansAmp lines. These things smoke. And my solid state Carvin amp ain't no slouch, either... So maybe trasistors will ALSO eliminate the gap.
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post #9 of 20 (permalink) Old 02-09-2004, 10:42 PM
 
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I don't buy the "as CD's are to records, so transistors will be to vinyl" argument for one simple reason-

A CD is supposed to be a flawless reproduction of an acoustical event.

A signal coming from a guitar amp, however, is not.

Digital is undeniably a cleaner medium than analog, but if cleanliness were what we were looking for, we'd all be plugging into the board direct, with nothing in between. We're looking to color the signal, and due to their inefficient nature, tubes do that quite nicely.

I think amp modeling has a tremendous amount of potential, and once companies like Line6 get off their "let's make this sound exactly like THAT" hangup, will push the boundaries of what was considered possible in a guitar tone QUITE a bit. However, at the same time, a tube amp has a very different response and feel than it's transistor bretheren, and i doubt it'll be superceeded anytime soon.

It's kinda like asking, "digital cameras offer perfect reproduction of anything you point them at. So, why do people still spend thousands if not millions on those old-fashioned, blurry, sloppy paintings by guys with French names? I mean, Monet? who the hell did HE think he was?"

-D
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post #10 of 20 (permalink) Old 02-10-2004, 03:35 AM
 
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Quote:
Originally Posted by Drew
It's kinda like asking, "digital cameras offer perfect reproduction of anything you point them at. So, why do people still spend thousands if not millions on those old-fashioned, blurry, sloppy paintings by guys with French names? I mean, Monet? who the hell did HE think he was?"
Slam dunk!
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post #11 of 20 (permalink) Old 02-10-2004, 03:53 AM
 
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Quote:
Originally Posted by Drew
I think amp modeling has a tremendous amount of potential, and once companies like Line6 get off their "let's make this sound exactly like THAT" hangup, will push the boundaries of what was considered possible in a guitar tone QUITE a bit.
I totally agree. If Line 6 started making completely new and fresh amps instead of combonations or amps that sound like vintage gear, guitar amps and digital modeling will go forht by leaps and bounds. Everyone always goes "I like Marshall, but not enough gain...gain too fuzzy" or "Mesa/Boogie Rectofiers are boomy and grainy" Line 6 could be like "here's 10 favorite amps, here's 10 Line 6 amps...now is a screen/knob that you can control perameter on the amp." Wouldn't you like to go I want my amp to sound like this...fiddle with a couple knobs and go "that's it...that's my sound" rather than "I bought a Marshall...didn't like it...got it modded...got close...bought a Bogner...got even closer...got it modded...made it sound better but not closer" This digital stuff is really scarey and I agree that Line 6 should be able to devistate amp companies in a few years. If not them another digital amp company. (BTW I still love tubes )
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post #12 of 20 (permalink) Old 02-10-2004, 04:06 AM
 
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Quote:
Originally Posted by The Madness Here
me and jester weren't so much saying that transistors will be the end of tubes, but digital amps will.

The advantage of digital is the ability to do just about anything.

Guitar amps can be simplfied to this. A signal goes into the amp, then a signal goes to the speaker. With digital processors, the signal that is sent to the speaker can be replicated. Right now, we can't get it exactly right, but we will be able to get it exactly right.
It's easy to model something linear and predictable. It's DAMN hard to model something as unpredictable as an overdriven guitar amp roaring through a 4x12. It's even hard to measure this stuff. For example the behavior of your tube guitar amp may depend on how hard you hit the strings half a second before any given note, because you could have drained the filtering capacitor(s) a bit deeper than usual and reduced the gain a bit by doing so. At every gain level a real tube amp will behave differently wrt. string dynamics, too. There's a lot more dynamic range being used when you're using the clean channel, and your preamp, amp and speaker become a "live" interdependent dynamic system that must be analyzed and modeled as such (meaning you need 10x the processing power to even begin doing things "right").

I'm not saying that modelling devices will never reach the level where they actually sound on par with tubes, I'm just saying that this day may be a little further than you think. After all 50 years ago scientists told everyone that we'll have artificial intelligence and flying cars in 50 years, and none of this became reality so far.
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post #13 of 20 (permalink) Old 02-10-2004, 04:14 AM
 
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Quote:
Originally Posted by bpd111
Quote:
Originally Posted by Drew
It's kinda like asking, "digital cameras offer perfect reproduction of anything you point them at. So, why do people still spend thousands if not millions on those old-fashioned, blurry, sloppy paintings by guys with French names? I mean, Monet? who the hell did HE think he was?"
Slam dunk!
There's another war being fought right now along these lines. It's Digital vs. Film. Arguments are the same - digital has convenience, instant gratification and costs a bit less if you factor in processing costs for film. On the other hand Digital is still inferior in terms of dynamic range, sharpness and color reproduction. In other words with digital you have to futz with things a lot to get a decent result, but the futzing itself was made a lot easier.
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post #14 of 20 (permalink) Old 02-10-2004, 04:53 AM Thread Starter
 
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Quote:
For example the behavior of your tube guitar amp may depend on how hard you hit the strings half a second before any given note, because you could have drained the filtering capacitor(s) a bit deeper than usual and reduced the gain a bit by doing so. At every gain level a real tube amp will behave differently wrt. string dynamics, too. There's a lot more dynamic range being used when you're using the clean channel, and your preamp, amp and speaker become a "live" interdependent dynamic system that must be analyzed and modeled as such (meaning you need 10x the processing power to even begin doing things "right").
Fair point dude, but quantum computing is just round the corner so get ready to kiss your tube amps goodby! A quantum computer of about 100 quibits (quantum bits) can perform calculations that would take trillions of years on todays top millitary and supercomputers in mere seconds, so all of the things you described could be assigned their own bit of signal infuencing code, and be then put onto a circuit.

Also at the moment, cant all of the stuff you were talking about be replicated using analog circuirty? I mean You could use components to mimic the effect of the signal change in a tube amp to give you a pretty close sound?

Could someone not pass a signal through a tube pushed hard, in a normal state, and when its expecting a signal. Then find out what comes out the other end and build a circuit/model the effect that will give the same result and stick it in the amp in place of a tube?
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post #15 of 20 (permalink) Old 02-10-2004, 09:44 AM
 
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[quote="agentdark45 Could someone not pass a signal through a tube pushed hard, in a normal state, and when its expecting a signal. Then find out what comes out the other end and build a circuit/model the effect that will give the same result and stick it in the amp in place of a tube?[/quote]

You missed half the point of this debate. Sure, you COULD do that... but you'd need to re-do it at every concieveable preamp gain and signal imput level... And there's no guarantee this would be a linear function (in fact, i'd imagine it's NOT) so in order to get 100% accuracy, you'd need to measure at an infinite # of points.

See the problem?

micro- re: digital cameras- yeah, one of my roomies is a photographer, so it's a debate i'm familiar with. It was just a conveniant example, though.

-D
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