About amp "immediacy"

[nsubulysses]

discourse saboteur

[Helmholtz]

Please, do not blame Matti Otala. I read his papers, and what he wrote makes sense and his work surely positively influenced amplifier design. He did not mention something like a 35mph electron speed - at least as far as I know.

[R.G.]

What happened to my humble thread? Why can't you guys just open up a new thread about this?

I think that the problem you're seeing with the thread not being responsive is
(1) It's not clear what "immediacy" is. A sizeable amount of the early part of the thread went into trying to define it.
(2) I offered to help design whatever it is if it can be described well enough to squeeze into electronics. If I don't know what it is, I can't design it.
(3) One of the posters hijacked the thread off into mysticism of "there are more things in heaven and earth, Horatio" with some counterculture attitude about physical facts. That doesn't go well with techies, as you have seen.
(5) The fellow who hijacked your thread does not respond to requests for hard facts or testable propositions. He responds only by attacking "authority" as the reason the world won't follow him. Again, not a popular position with techies.

I think the techies here would be happy to help if they could figure out what to do.

I think you could redirect the thread back to it's humble beginnings by reasserting your request - how to design for "immediacy". And tell us what "immediacy" is or might be, or even give us some idea what it might sound like. That is likely to re-direct the thread back to what you were interested in. You'd need to not feed the troll-bot to keep the wild theories from interfering with what you're trying to find out, though.

[Mike Sulzer]

tell us what "immediacy" is or might be, or even give us some idea what it might sound like.

I think you would have to go about it the other way:

1. Try many changes in amplifier design, determining which are significant and in what particular ways.

2. Describe some coherent subset of these changes, ones that interest you, by there name "immediacy".

Then you would know what "immediacy" is because you defined in it in terms of actual effects.

[DrGonz78]

Reading the original question to this thread I thought immediacy was something like touch sensitivity or something. That assumes we are talking about amps to use with guitars. At no point has the OP stated what input signal (instruments) we are using through the amp or even which amps can be taken as examples. Instead there was a thought that slew rate was a major factor or then could it involve much more...? All this talk about physics is quite enjoyable for me since it is entertaining and enlightening. Still I can hear Enzo in my head saying this isn't rocket science. Which as we know new members will join the forum to find help fixing an amp and will get caught up in the very finite details. In those circumstances it is told to the questioner that most of these amps have parts in them that have -/+20% tolerances. In fact, Leo (and perhaps others) were pretty adamant in replies about building a project amp that they should not get all bogged down with the idea of slew rate and focus on bigger fish. So what are we designing? What is immediacy? 150+ posts and we are still trying to gather information about the original post in the thread, since it has yet to be answered.

[rjb]

I think you would have to go about it the other way:

1. Try many changes...

So the method is, try a bunch of options & keep the ones you like.
That's pretty much my approach.
I call it design by dicking around.

-rb

[rjb]

Just making a wild guess at trying to translate subjective terms to physical properties:

This is the problem with limiting the desired outcome to just one, well understood parameter. We know the characteristic we want. We don't want to hear a note while we play the next one. If we're 50' from the speaker stacks, it could just be a matter of raising the treble response but I'm willing to bet there's more to it than that. A more aggressive decay profile will contribute to note definition. Is this part of the answer?

Someone else, I think Chuck (or maybe more than one person) mentioned a stiff power supply as possibly a component of an "immediate" amp.

Do any of these descriptions align with netfences' personal definition of "immediacy"?
If so, might one of the attributes he's seeking be described as "lack of compression"?

2nd order harmonics are known to emphasize notes in key and make them more quickly recognized. Is this contributing?

Is it contributing? I dunno. All I remember is that 2nd harmonic = one octave above the fundamental and 3rd harmonic = one twelfth (octave + perfect fifth) above the fundamental.
But I bet folks who remember Fourier analysis and/or play with soft vs hard and symmetrical vs asymmetrical clipping can design an amp that emphasizes 2nd order harmonics.
The question is, do 2nd order harmonics have anything to do with "immediacy"?

Hunh, whatever,
-rb

[R.G.]

@ netfences:
And just like that, we're back on topic. The central problem with your question is - what the devil is immediacy?

Good high frequency response? "Immediacy" seems to carry with it some hint of "do something quickly". High frequency response means the amp can make an output signal happen very quickly.

Is it as simple as not rolling off highs until you get out to the speaker?

Or is it slew rate? Slew rate was bandied about, as were the ideas of transient intermodulation distortion, and the time the amplifier takes to catch up with itself when it's fed a quickly changing input signal.

There are some problems with those. It's simple enough to calculate or test how quickly an amplifier's output can move in terms of volts per second, but the load on it interacts with this. How quickly can you raise your hand over your head? Depends on whether you have a feather in your hand or a 10 pound brick. The speakers ultimately have to get into this, as Mark pointed out - the cones have to move to move the air that you're going to hear. Simple physics says that the air isn't going to move any faster than the cones of the speakers push them.

Which brings up another issue - speakers. Maybe there are not more immediate amplifiers, only more immediate speakers. Or maybe it's a synergy thing - some amplifiers work better with some speakers' foibles.

[R.G.]

I think you would have to go about it the other way:
1. Try many changes in amplifier design, determining which are significant and in what particular ways.
2. Describe some coherent subset of these changes, ones that interest you, by there name "immediacy".
Then you would know what "immediacy" is because you defined in it in terms of actual effects.

Ouch!! I hope not. Because if that's the only way, it may be a long time indeed before we know what "immediacy" requires in an amp.

Here's a question though: who judges immediacy? For the question to have occurred, there must be someone somewhere that has talked (probably on the internet...) about the virtues of "immediacy". Do they get to be the judge? Or is there a school of immediacy disciples? Must immediacy listeners/judges be trained, selected for their special aptitudes? Or can anyone learn to hear immediacy? Do you lose the ability as you get old - another topic near and dear to my heart.

[Mike Sulzer]

Ouch!! I hope not. Because if that's the only way, it may be a long time indeed before we know what "immediacy" requires in an amp.

Here's a question though: who judges immediacy? For the question to have occurred, there must be someone somewhere that has talked (probably on the internet...) about the virtues of "immediacy". Do they get to be the judge? Or is there a school of immediacy disciples? Must immediacy listeners/judges be trained, selected for their special aptitudes? Or can anyone learn to hear immediacy? Do you lose the ability as you get old - another topic near and dear to my heart.

The ability to hear immediacy never declines. It can't.

[Leo_Gnardo]

Leo (and perhaps others) were pretty adamant in replies about building a project amp that they should not get all bogged down with the idea of slew rate and focus on bigger fish. So what are we designing? What is immediacy? 150+ posts and we are still trying to gather information about the original post in the thread, since it has yet to be answered.

Meanwhile the OT is whining about how we haven't designed his immediate sounding amp for him immediately. This kind of crap is why the clown car full of trolls have gotten their sorry-ass selves kicked off of one tech site after another. Like babies, all demands at one end, and nothing but irresponsible at the other. I did the best I could, but now the evidence is in, they are here to waste our time.

Thanks for the mention Gonz. As some have noted, I have a long fuse. But it does have an end. Paying customers need my attention. Their gear gets sorted out with old fashioned electric theory, no Captain Billy Whiz-Bang new age crap nonsense.

And now I'd like to put in a special word for Professor Sulzer and the rest of our brain trust at MEF. I'm sorry that you have been subjected to this crap. You've certainly done your best, and everything you've written here is first class. I hope you can get past this bad moment, and continue to contribute your wisdom to MEF. It's daunting to say the least, to be met with a barrage of nonsense from those who know nothing, who do their dastardly best to discourage those of us who do know our stuff. Good luck and I hope we can weather this storm of BS with no further damage.

[Mike Sulzer]

And now I'd like to put in a special word for Professor Sulzer and the rest of our brain trust at MEF. I'm sorry that you have been subjected to this crap. You've certainly done your best, and everything you've written here is first class. I hope you can get past this bad moment, and continue to contribute your wisdom to MEF. It's daunting to say the least, to be met with a barrage of nonsense from those who know nothing, who do their dastardly best to discourage those of us who do know our stuff. Good luck and I hope we can weather this storm of BS with no further damage.

Thanks!

[mikepukmel]

Reading the original question to this thread I thought immediacy was something like touch sensitivity or something. That assumes we are talking about amps to use with guitars. At no point has the OP stated what input signal (instruments) we are using through the amp or even which amps can be taken as examples. Instead there was a thought that slew rate was a major factor or then could it involve much more...? All this talk about physics is quite enjoyable for me since it is entertaining and enlightening. Still I can hear Enzo in my head saying this isn't rocket science. Which as we know new members will join the forum to find help fixing an amp and will get caught up in the very finite details. In those circumstances it is told to the questioner that most of these amps have parts in them that have -/+20% tolerances. In fact, Leo (and perhaps others) were pretty adamant in replies about building a project amp that they should not get all bogged down with the idea of slew rate and focus on bigger fish. So what are we designing? What is immediacy? 150+ posts and we are still trying to gather information about the original post in the thread, since it has yet to be answered.

Thanks Dr G!!! Yeah, I thought so as well. Lots of musicians use these vague terms, I've seen but there IS something there. There's a video by a marshall amp collector, on Youtube, he demos an old JTM45, one of the early ones. He said it has incredible touch sensitivity: you can go from fairly clean to full overdrive just by changing the touch of the pick.

[mikepukmel]

Ouch!! I hope not. Because if that's the only way, it may be a long time indeed before we know what "immediacy" requires in an amp.

Here's a question though: who judges immediacy? For the question to have occurred, there must be someone somewhere that has talked (probably on the internet...) about the virtues of "immediacy". Do they get to be the judge? Or is there a school of immediacy disciples? Must immediacy listeners/judges be trained, selected for their special aptitudes? Or can anyone learn to hear immediacy? Do you lose the ability as you get old - another topic near and dear to my heart.

You guys on this blog are amp wizards. I bet if you came up with a technical definition, you could get it put into wikipedia, then it would be written in electrons, forever.

[Chuck H]

...you won't even get your first note out before the drummer finishes the entire first set and has left for the bar.

I've had trouble with that at times anyway