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Good read on "The Great Debate"

#201
Downunderwonder said:
You can't hide behind not being able to model sag or capacitors in a live playing test all the while making out Jimmy is delusional for saying he can pick the difference with his eyes shut.
Click to expand...

I said sag IS MODELED
The whole amp is, imperfections and all. It's all there. Give a try, or nevermind.

I think I'm through with your proposal. It has to be hands on or we'll see claims of "feel" were missing from the results, just like all the other online tests done.

There's nothing except independent third party blind testing that is going to be fair. This would include picking of subjects for the test. Else we end up in another TCE controversy.
 
#202
You're through with the proposal because it involves live testing of the modelling? That was the proposal, to take the online recording aspect out of it.

As to picking test subjects, the test is "can a tube nut tell when he's playing a tube amp?" For that you need self ascribed tube nuts the likes of Jimmy and the others getting up you every time this comes up. That rules you out of putting yourself forward for the testing but not for helping come up with the test regime to end it all.
 
#204
Since this thread came up, I've been trying to think of how I can put into words the "feel" of tube amps that explains how I can tell when I'm playing them. I think I finally came up with it.

1. People automatically think "tube = compression" but I don't hear them that way. Sure, when you crank them they're compressing, but when you run them clean, I don't know if the signal is technically being compressed by tubes or not, but it doesn't sound like it to me. They actually sound to me the least compressed of any amps I've ever played as long as I'm running them with decent headroom. No matter how hard I dig in, they dig in with me. No matter how softly I play, they go that much softer. I don't get that dynamic response in solid state designs. They always seem to have a point where they don't follow my dynamics that closely. Some do a really good job with it, but none pick up on the most subtle nuances of it like a clean running tube amp does.

2. I don't think the sheer physicality of your signal traveling through giant iron transformers and a network of glass-enclosed vacuum tubes can be taken for granted. All those little wires getting heated up, all that glass getting heated up, your bass signal traveling up and down that network of iron and glass until it hits the speakers...you can feel it when you play the bass or guitar and you can hear it when you've educated your ear to the difference. The emulations do very good at duplicating those sounds, but I think that physical reaction just can't be duplicated.

But one day, I do believe Seamonkey will be right about his claims that SS technology can emulate everything about tubes. I never thought they could even come close, and it's only been in the last few years that I think they have. But I've heard recordings of them and I'm hard pressed to tell the difference whereas I always believed I could in the past. The emulations are quite good now, and it's only a matter of time before it can all be duplicated, feel and all. But that's how I can best describe the "feel" differences I notice when I play a tube amp vs a solid state emulation, and that's why I don't think it's there yet.
 
#206
seamonkey said:
Sorry. I misunderstood.

Live, hands on, run by independent third party, witnessed, etc. it could be worked out, but sounds like money.

Similar to this without the money:
Challenge Info
Click to expand...
The implication is all those in the JImmy camp are soothsayers who can't come up with the goods under examination.

What is the SS modelling amp to test these guys out with?

That Carvin fella took two days locked in a hotel room to physically model a megabuck hifi tube amp down to audiophile confoundment. How long do you need with all your soundcard sims? I've given you 2 years. That's pretty generous I think. Away with you to come back with the SVT killer that Jimmy can't tell from a real one.
 
#209
Seamonkey, you keep referring to the conclusion of this and other tests. Just for clarification, I would like you to point out exactly which part of the following you think is the relevant and indisputable argument in this debate? Reading their conclusion, as well as the part about the limitations of the test, I don't see any really bold universal claims, and can't help but put a fair bit of emphasis on the very circumstantial nature of their findings. It was noted earlier in the test that the investigation of power amp clipping was cut short after an initial testing with only six participants. They also note that preamp clipping was not thoroughly investigated in this paper, and so their conclusion about harmonic content of clipped signals doesn't have a very strong foundation. With the general agreement that frequency response can be emulated, are these not relevant points in this debate?

As mentioned before, the method may be valid, but the findings are fairly irrelevant, don't you agree?

"CONCLUSION

Listening tests indicate to[sic] causes for differences in perceived sound of tube and transistor guitar amplifiers. These are ripple intermodulation distortion and frequency response differences caused by the reactive speaker load interaction with the output impedance of the amplifier. Although ripple intermodulation distortion is easily detected by trained listeners, only one of seventeen test subjects was able to detect it without tranining. The change in frequency response caused by the high output impedance of the tube amp is by far the predominant cause for differences.

The differences in speaker damping were not detected by the listeners. Also not detected were the differences in the harmonic content of an overloaded signal in teh[sic] power amplifiers."

Also, disregarding Jimmy's and others' input in this debate seems like a bad idea if we want to exchange information and all get a bit smarter. Selective reading doesn't go well with constructive debate.

Martin
 
#210
JimmyM said:
Since this thread came up, I've been trying to think of how I can put into words the "feel" of tube amps that explains how I can tell when I'm playing them. I think I finally came up with it.

1. People automatically think "tube = compression" but I don't hear them that way. Sure, when you crank them they're compressing, but when you run them clean, I don't know if the signal is technically being compressed by tubes or not, but it doesn't sound like it to me. They actually sound to me the least compressed of any amps I've ever played as long as I'm running them with decent headroom. No matter how hard I dig in, they dig in with me. No matter how softly I play, they go that much softer. I don't get that dynamic response in solid state designs. They always seem to have a point where they don't follow my dynamics that closely. Some do a really good job with it, but none pick up on the most subtle nuances of it like a clean running tube amp does.

2. I don't think the sheer physicality of your signal traveling through giant iron transformers and a network of glass-enclosed vacuum tubes can be taken for granted. All those little wires getting heated up, all that glass getting heated up, your bass signal traveling up and down that network of iron and glass until it hits the speakers...you can feel it when you play the bass or guitar and you can hear it when you've educated your ear to the difference. The emulations do very good at duplicating those sounds, but I think that physical reaction just can't be duplicated.

But one day, I do believe Seamonkey will be right about his claims that SS technology can emulate everything about tubes. I never thought they could even come close, and it's only been in the last few years that I think they have. But I've heard recordings of them and I'm hard pressed to tell the difference whereas I always believed I could in the past. The emulations are quite good now, and it's only a matter of time before it can all be duplicated, feel and all. But that's how I can best describe the "feel" differences I notice when I play a tube amp vs a solid state emulation, and that's why I don't think it's there yet.
Click to expand...

Pretty much how I feel about the state of the art, including your conclusion.

I've no doubt the technology is there already or will be soon enough, at least to satisfy myself and the majority of people who generally prefer or want to have the option of certain well known tube amp tonalities, including the distortion characteristics and 'feel'.

I am no diehard and all I ever wanted was a bit confirmation that I wasn't crazy for preferring and seemingly recognizing a desirable quality that many tube amps I've played displayed.
 
#212
Faderoktopus said:
Seamonkey, you keep referring to the conclusion of this and other tests. Just for clarification, I would like you to point out exactly which part of the following you think is the relevant and indisputable argument in this debate? Reading their conclusion, as well as the part about the limitations of the test, I don't see any really bold universal claims, and can't help but put a fair bit of emphasis on the very circumstantial nature of their findings. It was noted earlier in the test that the investigation of power amp clipping was cut short after an initial testing with only six participants. They also note that preamp clipping was not thoroughly investigated in this paper, and so their conclusion about harmonic content of clipped signals doesn't have a very strong foundation. With the general agreement that frequency response can be emulated, are these not relevant points in this debate?

As mentioned before, the method may be valid, but the findings are fairly irrelevant, don't you agree?

...

 Also, disregarding Jimmy's and others' input in this debate seems like a bad idea if we want to exchange information and all get a bit smarter. Selective reading doesn't go well with constructive debate.

Martin
Click to expand...

I'd like to go back to the original article and not the mangled one floating around. I don't have access to IEEE, and I think Milbert overstepped their "Fair Use" of this paper.

There is a pdf photocopy here
Invalid Link Removed

Note there is no need for your "sic" annotation. The original does not have the typos as the Milbert manual copy does.

I will not mutilate the paper worst by trying to copy screen shots. Or retyping it myself.

The authors list what they found were the differences from the study. They did not list anything else. One subject did say they heard something else. This subject could here the ripple intermodulation distortion and this is disclosed in the conclusion. All the extra sonic properties often repeated in forums is not mentioned in the conclusion. If they exist, other sonic properties didn't seem worth mentioning, but ripple intermodulation distortion was?

Essentially - there is no differences in the sound according to 17 pro and semi-pro guitarist.

It's not actually indisputable, it just hasn't yet been disputed by any equal study since it was published.
 
#214
Downunderwonder said:
You can't hide behind not being able to model sag or capacitors in a live playing test all the while making out Jimmy is delusional for saying he can pick the difference with his eyes shut.
Click to expand...

Dude... power supply sag is about the easiest thing in the world to recreate in a live playing test. Of all the "tube" based differences to model that may be by far the simplest to recreate in an SS head.
 
#215
Here's some more fuel to the fire of ss modeling tube performance.

Invalid Link Removed

I'm aware the modeling/transfer function designs used were within the linear region of the power curve in these tests and MI amps are overdriven somewhat in a lot of cases to get their tonal signature.
 
#216
JimmyM said:
Since this thread came up, I've been trying to think of how I can put into words the "feel" of tube amps that explains how I can tell when I'm playing them. I think I finally came up with it.

1. People automatically think "tube = compression" but I don't hear them that way. Sure, when you crank them they're compressing, but when you run them clean, I don't know if the signal is technically being compressed by tubes or not, but it doesn't sound like it to me. They actually sound to me the least compressed of any amps I've ever played as long as I'm running them with decent headroom. No matter how hard I dig in, they dig in with me. No matter how softly I play, they go that much softer. I don't get that dynamic response in solid state designs. They always seem to have a point where they don't follow my dynamics that closely. Some do a really good job with it, but none pick up on the most subtle nuances of it like a clean running tube amp does.

2. I don't think the sheer physicality of your signal traveling through giant iron transformers and a network of glass-enclosed vacuum tubes can be taken for granted. All those little wires getting heated up, all that glass getting heated up, your bass signal traveling up and down that network of iron and glass until it hits the speakers...you can feel it when you play the bass or guitar and you can hear it when you've educated your ear to the difference. The emulations do very good at duplicating those sounds, but I think that physical reaction just can't be duplicated.

But one day, I do believe Seamonkey will be right about his claims that SS technology can emulate everything about tubes. I never thought they could even come close, and it's only been in the last few years that I think they have. But I've heard recordings of them and I'm hard pressed to tell the difference whereas I always believed I could in the past. The emulations are quite good now, and it's only a matter of time before it can all be duplicated, feel and all. But that's how I can best describe the "feel" differences I notice when I play a tube amp vs a solid state emulation, and that's why I don't think it's there yet.
Click to expand...

This is a very good way at trying to describe this and it pretty much mirrors my take on the whole thing. I'd freely admit I can't tell them apart in many recordings, but it becomes painfully obvious when you plug into one, or are in the same room with one being played. That part involves physical interaction with the instrument and the system, not just listening only.

I don't doubt someday the technology will get it, but not today. Someday we all might be plugging into smartphones or just have computer chips inside the bass beam the sound directly into people brains, but now, we are where we are and the emulation still can't match the real thing, at least not to the player.
 
#217
aborgman said:
Dude... power supply sag is about the easiest thing in the world to recreate in a live playing test. Of all the "tube" based differences to model that may be by far the simplest to recreate in an SS head.
Click to expand...

Maybe. I'm not tech enough to explain all this but one of the many Valve Jr. mods out there involves just putting a resistor inline with one of the transformer wires to give it sag. Vary the resistor value for more or less sag. Of course, this is a tube amp with an SS rectifier emulating a tube rectifier. It reportedly works, but I don't know if the amount of sag will vary with your playing dynamics and amp output like a real one, I'll know after I do the mod to mine. I would imagine you could do something similair to an SS amp if you wanted to.
 
#218
will33 said:
Maybe. I'm not tech enough to explain all this but one of the many Valve Jr. mods out there involves just putting a resistor inline with one of the transformer wires to give it sag. Vary the resistor value for more or less sag.
Click to expand...

Yes - this is how you change sag. You increase/decrease the output impedance of your power supply.

will33 said:
Of course, this is a tube amp with an SS rectifier emulating a tube rectifier. It reportedly works, but I don't know if the amount of sag will vary with your playing dynamics and amp output like a real one, I'll know after I do the mod to mine.
Click to expand...

It will.

It's basic Ohms law. V=IR.

Your supply voltage will sag by the current times resistance - whether we're talking tube rectified transformer based supply, or completely solid state SMPS.
 
#219
aborgman said:
Yes - this is how you change sag. You increase/decrease the output impedance of your power supply.



It will.

It's basic Ohms law. V=IR.

Your supply voltage will sag by the current times resistance - whether we're talking tube rectified transformer based supply, or completely solid state SMPS.
Click to expand...

Makes me wonder why it isn't done more often, at least in SS amps shooting for a warmer, thicker "tubey" tone.
 

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