When you start talking about professional gear, the cost of modeling amps is more than tubes.

I'd also contest that this is "figured out" - this area is actively researched.

For a stadium band. It makes the stage setup much easier. No cabinets, mics and low stage volume. Each member gets a rack with two units (backup) and you are done. Sound will be always the same. Less likely to fail.

For a small band, you don't need the bulky rack editions. You get the same sound quality in pedal form (Helix, FM-3, etc). It can be carried in a bag.

In both cases, the sound engineer has an easier job. You plug your devices directly to the mixer/Front of House.

Most musicians program few pre-defined rigs, but a device like this gives you not only one sound, but the sound of ~300 amplifier models including some rare collection items.

And for a small band even if you have a FoH mix, it's going to sound better out of a 40W combo than through whatever PA your vocalist dragged along. But that's just my opinion.

Digital models do a good job in a vacuum (no pun intended). They do a very poor job of modeling how a guitar and FX chain load and drive the preamp of an real tube amplifier (which is really difficult to capture in either white or black box models). That's also a key to getting lush and evocative ranges of tone from a single configuration.

Just speaking as a player, I don't really fiddle with my tube amps all that much. The tone changes come from dynamics of my hands and controls over my pickup volume controls, and it's accentuated by my drive and boost pedals. That kind of play doesn't translate well to modeling amps which don't have the low headroom, lower impedance inputs of a pure tube stage. I don't need 300 different amp models, I need 1 amp model for 300 tones.

I don’t know what your idea of “lower impedance” but a pure tube stage has an input impedance that measures close to open. Off the range of my multimeter, I bet. You just see the Miller capacitance and with the grid-plate somewhere around 1.6pF and maybe 20dB gain, it’s not a lot. The input impedance of the guitar amp is usually dominated by the 1 MΩ resistor to ground, and the tube barely registers because the input impedance of a preamp tube is so high. This is usually considered “high impedance” (as opposed to “ultra high” like you see in a piezo amp, which might run 10 MΩ).

It is very common to see solid-state equipment with lower input impedances, especially guitar pedals.

There’s a lot of weird voodoo electronics repeated around guitarist’s forums so you got to watch out. Just quick fact check: small tubes = high impedance input, in most normal configurations, normal operating conditions (cathode is positive relative to grid).

Just as another point of reference—this is why you hear about “tube microphones”. These microphones have a vacuum tube inside them as a preamp / buffer, and the reason you might want to use a tube for these applications is precisely because the input impedance is so high. When they moved away from tube mics what you see replacing them is something like a FET, possibly bootstrapped, to try and replicate the naturally high impedance of a tube.

That's a million ohms so not much of your guitar signal is wasted passing through it to ground.

The input impedance of the tube reacts dynamically according to the signal coming in, and the often dynamic behavior of whatever is plugged directly into it.

When that's just your guitar without any pedals or anything, that can be the most dynamic from a touch-sensitive point of view.

Are there ABX tests for digital vs. physical tubes?

ABX test is definitely the wrong type of test here. It is only really useful for testing if there are differences, and in general a tube amp and a digital sim are not going to sound the same as each other. What I’ve seen as more common is that you’ll have someone playing blind through a selection of digital models and tube amps. If you’re lucky, the digital models and tube amps may be closely matched, but that’s not necessarily the only way you would want to run a test.

There are also an incredible number of different scenarios that need to be taken into account in a simulation, so you’d want to try different styles of amp. Various overdrive scenarios are harder to simulate, broadly speaking.

https://www.youtube.com/watch?v=k6AwTp4ZUm0

Note in this video, the speakers are being simulated for the tube amps. So it’s a bit of an unusual comparison, it’s just something I found.

I've been in high end music retail for several years and even the big name stars we deal with are buying primarily combo tube amps in the 40w range.

The katana and fender GT sound "fine" but the assertion that they can model traditional tube amps well enough for stage use is also a little suspect. Those specific amps sound thin and lifeless compared to the amps they attempt to model.

Where these types of amps shine is that they're lighter and you can have a more consistent sound at lower volumes. For a person in their house who isn't really worried about having a specific sound or may not even know the difference between british and american voiced amps these are great options. Also the volume issue only comes into play when we're thinking about gain and compression. My fender Deluxe Reverb sounds amazing at low volume.

The AxeFx and helix stuff is a little better but that stuff is way more expensive than your average tube amp, particularly on the used market. Your average 40 watt tube amp from fender, vox, marshall, etc will run you $700-$1500 while these high end modellers can easily be $2500+.

As far as tube amps being unreliable goes I'd love to see some sources on that. I've played fender amps from the 50s and marshalls from the 60s that sound every bit as good today as they did when they were made.

I work in very high end music retail where I'm fortunate enough to get to play all kinds of new and very old gear. I can confidently say that modelling is getting better and has drastically improved in the last 20 years but still has a ways to go if it's going to completely replace tube amps for stage and studio use.

But the same fingertips can not even be trained to fully master the pallette available from a simple amp like a vintage Champ or Bassman without even reverb or tremolo.

Careful choice of guitar, pickups, strings, tubes and speakers each broaden the pallette and build on each other and these are all user selectable, just nowhere near as convenient as changing digital models. Also most vintage pro amps in excellent working condition or fully restored are more reliable than the cabinets, whose reliability mainly depended on how high it fell off the truck from. You're supposed to have spare guitars, cables & strings anyway, plus tubes and an extension speaker to avoid show-stoppers if you only have one amp.

Transistor amps shouldn't be turned on in direct sun either, but they can last quite a bit longer before expiration.

We had a very talented guitarist locally who had a great sounding Line 6 100 watt 2x12 which lasted a long time, but replaced by an older, longer-lasting Twin Reverb he regained a certain stonk that you could tell had an effect on the dance floor.

Maybe on the low end of the market, but tube amps still reign supreme for most serious players.

There are many advantages. Less maintenance, lower stage volumes, better for in-ear-monitoring use, sound consistency, less weight to carry, and the ability to explore hundred of amps sounds with a single device eg. check https://wiki.fractalaudio.com/wiki/index.php?title=Amplifier...

I would be pretty surprised if Metallica were using the technology you are describing. They have an extremely consistent setup that has worked for decades and an effectively infinite budget.

That’s just one concrete example.

I think a lot of the comments in this thread are missing the fact that if a player thinks a thing has irreproducable properties, they may be happier and more creative while using it.

https://www.youtube.com/watch?v=P6k2ghtbhoU 3:09-7:32.

Megadeth is also using AxeFX. https://www.youtube.com/watch?v=O7vzOjzn0Mw

And from there you can extrapolate how common they are.

But as far as guitar instrumentation goes— I have a lot of respect for good solid state amplifiers—think Roland Jazz Chorus—that are not modelling another sound but a very intensively tuned original instrument.

As for physical, electrical amplifiers versus a software emulated version I just can’t see the point in using one outside of the [potential] convenience.

Now, if your goal is to take that signal and twist it into something new altogether that’s different. But if I want to sound like an AC30 I don’t know why I would use something like hats just trying to sound like an AC30 versus something that is and AC30.

Lacklustre has always been my experience. Like leaving a tube amp too quiet—not saturating the tubes. It just tends to sound dull.

So that's why I want it to be good... But it's not.

The Kemper is far more credible, with the AxeFX system and and some of the better amp sim plugins you can buy from (say) UAD following behind.

The volume required to crank and get the best of it sounds it makes it too loud for almost any residential area.

One of the best features of modeling amps is that you can get the sound of a cranked amp set at a high volume, with low/moderate real volume or even with head-phones.

Even in a rehearsal room, real amps are too loud and make the band members start competing for volume. Low stage volume and in-ear-monitoring allows me to play better.

Guitar players always think you need a gigantic marshall stack to get good tone when for most people that is way too much and they'll never hear it the way it's supposed to sound.

As a teenager I played a Hot Rod Deluxe (40W!) in my parents' basement with no real complaints.

It’s not like a stereo where 15W is weak. A 15W guitar amp is pretty damn loud.

If you don’t crank it then I don’t see the point. Or don’t hear it, anyway. I can’t stand the sound of a clean Vox. It’s gotta have some grit.

I am under the impression I am well read on this topic, and I don’t recognize that claim.

It could be that you just like the volume. The speakers in the AC15 are fantastic. Or it could be you don’t think of it as gritty, but I do.

Of course, most people won’t be able to tell the difference, but many musicians tend to prefer analog.

That, and your experience affects your performance. It’s easier for an actor to act in a room full of props and other actors, versus a green screen. Easier for a musician to make music with the gear and tone that they prefer.

Can you explain this a bit more? I do not see this is commonly true, it is the exception and not the rule in many cases of 'someone and their audience'.

It might be true that that 'someone' believes it, however misguided.

But audiences tend not to care about specifics. They care if you can live up to expectations and provide the experience they expect. So if a performance is lacklustre, or a piece of software is stupidly designed from their POV, they'll know something has gone wrong - but they won't know (or care) exactly why.

Amateurs and wannabes tend to fethishise equipment instead of art. There's a lot of "If only I had that equipment I could do this properly."

The reality is that expensive pro-grade equipment only ever adds a final layer of polish. It's also good at not getting in the way with unnecessary frills and complications.

So a world-class professional with a budget guitar will always outplay and outperform an amateur with a pro-league instrument. No exceptions. And a professional photographer will always take better photos with your phone than you will. And so on.

The professional may notice some polish is missing and they may have to work harder than usual - but they will be able to do the job, while an amateur won't, no matter what they're using.

But a nicer instrument is a pleasure to have, and provides me with the assurance that anything wrong with my sound is strictly a matter of improving my own abilities. So it's a challenge to live up to the quality of my instrument.

One thing is that the audience only has to tolerate your sound for a couple of hours, and can always seek refuge at the bar or just go home. You have to hear it over and over, night after night. You also have to hear it at home. As an amateur, most of my playing time occurs in my own living room.

Another thing is that there's a layer of the performance above the basic sound of the instruments, that the audience might perceive even if they can't quite put their finger on what it is. It's what separates a great performance from a dull one. We're all trying to find what that thing is, and it involves exploration on many fronts, including how we choose and optimize our instruments.

Even Metallica is running all digital for their love shows. Although they do still mic up for studio work.

No one has mentioned Kemper yet, and Kemper - made by the same programmer who developed the Acccess Virus DSP synth - is the go-to modelling system for pros and serious wannabes.

This is really a solved problem. DSP won. You can freight multiple valve heads around if you really want to, but no one in the audience or the rest of the band is going to notice, never mind care.

Ehh only on the lower end. Most mid to pro musicians still use tube amps.

The modeling amps are good but tube still sounds better.

I have never ever noticed any latency issues with any physical hardware, even for equipment from years ago.

If you're doing all of the emulation and signal processing on a general-purpose computer, then sure, you often run into latency problems, and part of the set up process for those software tools is latency calibration. The one that I use when at my desktop, Guitarix, is very conservative with its latency, defaulting to like 500 milliseconds, I turn it down to 20-30 or so and it still functions on my hardware and you can't tell the difference: it's the same time delay as playing through a speaker 20 feet away.