Absolutely. I have a strong feeling these tubes are never going to "sound" quite the same unless they look (and basically are) just like the genuine originals. The placebo effect is incredibly strong.
I'm surprised the government didn't outlaw tubes along with all the incandescent bulbs. That's just the kind of collateral damage they never seem to consider.
If they put the same coating on the anode as what they put in the vacuum-fluorescent displays, it will have more than just that warm glow. It will flicker green.
From the photo, it looks like that may be the case: what are those green squares? The form factor is like that of a VFD.
It is quite suggestive of the intent that the part will be mounted such that it is visible through a display window in the equipment's case.
In addition, when tubes are pushed, the distortion comes on gradually and those even harmonics give a pleasant tone. This is why almost all rock guitarists use tube amplifiers despite the fact that they cost multiples over equivalent powered solid state amps.
I don't see where the article says that they are. It says that the tubes are designed for musical instrument applications to generate rich harmonics. Essentially, the distortion characteristics of a tube amplifier are different from those of modern designs, and these characteristics are sometimes desired in for example guitar distortion pedals.
Korg has previously released synthesizers and a sampler using vacuum tubes for effect rather than to make them "better" in any objective sense.
They're highly non-linear wrt amplitude and frequency, in a pleasing way.
This makes them almost instruments in their own right. When playing a guitar through heavy tube distortion, the tubes react to your playing very sensitively, just like the guitar itself does.
When people describe random pieces of electronic equipment as "musical" this is usually what they mean.
This applies to IC amps as well, but not to the same extent. The recent history of music tech is a story of working hard with esoteric techniques to produce amazing music from primitive gear in the 60s and 70s, then inventing more reliable and repeatable techniques using digital technology in the 80s and 90s.
In recent years, people are realising that the man-vs-machine-vs-physics attrition of the mid to late 20th century actually led to a certain sonic complexity that has been missing in recent years. So now we see these hybrid products which merge old and new technology to get a deep sound while retaining reliability and a good workflow.
See also: analog voltage controlled oscillators which automatically tune themselves using digital clocks, and compensate for temerature changes.
(Incidentally, a lot of audiophile nonsense stems from them making category errors between their puported search for crystal clear reproduction, and studio engineers' quest for signal distortion with emotional quality. This is similar to how MBA types cargo cult programming terminology.)
it plays into that old joke about audiophiles listening to hardware. Perhaps the distortion has properties that ICs fail to emulate, or likely put three of these guys in a room and a blind listening test will have four results.
I will expand on a comment below. Tubes usually distort with even order harmonics which means the distortion is usually in key with the note and our brains find this distortion pleasing. Transistors distort with odd order harmonics which sounds more dissonant and harsh to the ears. Transistors also tend to be clean or clip, there is little to no build up. Tubes saturate gradually and can make things sound "warmer, fuller and generally awesome".
Not all tubes are great though and it doesn't look like these are power tubes so it would be for preamp/line level gear only. Either way I'm really excited to see this.
That's a two-segment vacuum fluorescent display! If you want to do your own "tube" experiments, you can find these in salvaged electrical gear, especially VCRs.
Generally with tube amps there are two places the tubes can go, either the preamp stage or the output stage. Most tube amp enthusiasts will scoff at the idea of having only a preamp tube stage and not power tube stage. These things look tiny, I'd be impressed if these can deliver the wattage required by output tubes.
Also interesting will be to hear how they actually sound. All tubes aren't built equal, and even with traditional tubes you can find people arguing about the merits of the 6L6 or EL-34.
Of course, if this thing delivers on both fronts that would be incredible. Tubes are in short supply, and my friends who play on tube amps are always complaining out how expensive it is to replace the damn things.
Maintenance is expensive for sure and new old stock is scarce. But there it's not only tube amps vs solid state amps, there are also modeling amps. They've been around for more than a decade and they are able to simulate the effect of tube amplification and even model each electronic component individually. Well at least they pretend they do. And anyway even if they did guitarist would not buy them because they are a little conservative.
I have Axe-Fx II, it is amazing, and from my understanding no one can tell the difference anymore, which is why so many big and small names have switched over, like Steve Vai and Metallica: http://www.fractalaudio.com/artists.php
Do they use it live though? I thought Vai was entirely Carvin? His sound has more sheen on it recently compared to his earlier stuff.
Also, I notice they list Petrucci as an artist. I had a look on stage at his rig last tour (fortunate to do so, was I) and I am sure it was entirely Mesa Rectifier MIDI enabled preamps and Mesa Simul-Class2:Ninety rigs for the amplification, ran to two small 12" (or 10") cabs miked up offstage (so less bleed from live drums, more control over the sound) so I am curious where he actually uses this in his signal chain? I doubt he actually uses it for anything other than effects???
Same for Myung - he was using a DI box and a Demeter power amp ran on a dummy load for overdrive. (I chatted with the bass tech, friendly guy! The entire crew were friendly!)
Yeah, one of the biggest advantages of Axe-FX is just how much equipment is packed into a small box. That is one biggest reasons I read for Metallica to use it, they used to drive around tons of equipment.
From what I've seen on youtube of setup run throughs, people almost always have a complete non-fractal set of equipment for backup, but an axe-fx patch can actually contain all of this equipment. Manufacturers even sell their own racks that can be loaded into axe-fx.
Can't find any more recent info. Pretty sure Petrucci does the same thing, with Axe-Fx as effects processor rather than amp modeler. Don't know about Metallica.
There are quite a few artists who do use the Axe-Fx or Kemper live in lieu of amps though: Animals as Leaders, Periphery, Paul Masvidal from Cynic, Devin Townsend (sometimes, he seems to switch back and forth a lot), Jeff Loomis in Arch Enemy uses a Kemper live (https://www.youtube.com/watch?v=J92RP-fFO_g). Plus quite a few lesser known musicians. If you have an Axe-Fx, you can do a fly-in gig with it and have a consistent sound without being at the mercy of whatever crappy backline the venue has. Handy tool for a guitarist for hire.
Especially in metal though, there's a certain showmanship aspect to having a bunch of big loud amps on stage. A lot of the bigger bands for years have even lined stages with dummy stacks of 4x12 cabinets just for show. So even if they start using a modeler, they probably won't make a big deal of it. Smaller bands, playing in smaller venues run into the problem of stage monitoring. You can run your Axe-Fx into front-of-house and probably get a good sound to the crowd, but a lot of the smaller venues have lousy monitoring setups on stage and guitarists are used to essentially using their amp to compensate for that. So you might still want a power amp and cabinet on stage in that case.
Anyway, I have an Axe-Fx II and it's replaced all my tube gear. I wouldn't say it sounds 100% the same, but it's really close. Beyond the sound, what it does that other modelers have not done so well is get the "feel" of playing through a tube amp. The really subtle dynamics and compression that you don't necessarily hear but that affect how you play when your ears and hands are reacting to what the amp does. Leaps and bounds better than Line6 or Podfarm. And at apartment-safe volume levels, I'd even argue that it sounds better than most tube amps, so that's a huge plus for me.
Modelling amplifiers do a variable job. Some of the cheap models sound horrible and harsh, and even the more expensive ones can sound harsh and not warm at all. In particular, I have noticed that any bass amp modeller only does nasally distortion in the style of a completely overdriven SVT with the mids boosted, completely different to real amps or even preamps like the SWR Interstellar Overdrive etc.
Even the guitar amp simulators in apps like Logic Pro X sound pretty ropey. My friend (who is an excellent guitarist and teaches many many people) struggled to get a good sound out of it, and I really did as guitar amps are completely alien to me (why a presence control eh? why not just leave it on 10 and let the treble do the job???). To be fair to the developers of the software based ones, they make a good attempt but amp simulators never ever sound like the real things.
In my defence I used to use them for a while as a bass player but now am entirely analogue, with real glowing warm things in my gear. The difference is like chalk and cheese. I confess I always valves in the preamp stages - I do have one that uses an EL84 (normally a power amp valve) in the preamp stage combined with a 12AX7 for a great round sound; I used class D for the power amp because I don't want my back to break carrying gear).
I have played for 20+ years and my ability these nuances has improved, so I wouldn't have heard the difference to begin with, that's for sure. Pity my ears have been subjected to drummers in that time, or I would hear the differences far better!
Valves are very difficult to model. Noob DSP designers think 'even order harmonics!', so they slap a Chebyshev polynomial in the chain and half the time they don't even remember you have to oversample to avoid aliasing.
The hardware valve sound is a mix of compression, microphony, and at least two different kinds of distortion - and probably other things no one has figured out yet.
Distortion is unexpectedly complicated on its own. A while back I looked into models that use a Volterra series, and the math soon got very scary.
Doing it properly could potentially be a machine learning problem. I seriously doubt it's possible to reduce good distortion to a simple one-line equation - even a very long one with lots of coeffs.
Not to mention all the little variables, like temperature and voltage. I saw a video segment with Brian May's guitar tech and they run a very very specific voltage into his AC30 amps. A difference of 2-3v from nomimal will be audible, at least to them, and being out more than 5v or so effected tube life. This also lets them run 220v amps anywhere in the world.
I'm looking at some Noritake data sheets for VFD's.
Looks like you could possibly just use those things as distortion elements.
From the picture it looks like this part is a dual triode device. The groups of three pins on either side are the anode/grid/cathode, and the four pins in the middle are separate filament circuits. 12AX7 and similar tubes usually have only three pins for two filaments: the filaments are in series with a center tap for hooking them up in parallel.
If this thing is similar to VFD's, it can probably run at around 20V for the anode voltage, and a small voltage for the filaments, around 2V.
It would be interesting to develop a tube board for the ADA MP-1 guitar pre-amp with these things. The stock one uses a pair of 12AX7's. A 9V power feed is used for the filaments, and 190V for the anode voltage. That could all be gutted out, and a simpler transformer used which doesn't provide a high voltage tap. The silicon side of the MP-1 runs on +/-15V rails; the same underlying transformer tap could could power the Noritake tubes.
I wonder if you could do some kind of crazy circuit bending by turning the VFD into a distortion device, with the characters displayed on the unit as part of the input.
unrelated aside since you linked to such an interesting web page.
this 1940 vacuum tube hearing aid used a bone-conducting transducer scheme.[1] I was stuck thinking that was a fairly new concept (at least from the 80s) for military comms, and was intrigued by the use of such tech in the recent Google Glass.
It's cool to see that the idea was much older than I realized.
Cool concept, but I doubt the operating range of these tubes is large enough to get any sort of usable gain out. Unless there's a datasheet that says otherwise I'd imagine these are going to end up early in the gain chain as a "coloring" component.
With the low operating range and low bias point you don't get the same effect as you do with a tube biased to it's sweet spot. It seems like a marketing gimmick like the starved-plate 12ax7 stage they put in everything nowadays (with ~12V B+ as opposed to the 250-400V B+ you find in nearly all classic amp designs), along with a few LEDs and a window in front so you can see where your extra $100 is going.
If you plot (really any) load line on the plate curves for a 12AX7 with a < 50V B+ you're in a really poor, highly non-linear region. Looking at plate curves for some old VFD tubes the operating range for those is way down in the same region in the lower left corner if you plot them over the 12AX7 plate curves.
Given the size and the fact that it uses 2% of the power of conventional tubes, I doubt that these tubes could be used as an output stage. I would have to guess that they're running them cold as well. Preamp tube power draw is often dominated by the heaters
Of course this is all speculation until they publish a datasheet...
Yes but not all non-linearity. With a high plate voltage (and a reasonable bias point) you get gentle compression as the tube starts to break up. That's the good (T00B) sound, with the even harmonics and everything.
When you run a low plate voltage you start to run into some of the undesirable things that happen when you get close to the point where the tube stops conducting entirely. you start to hard-clip the signal on one half-cycle and all those odd square-wave harmonics start to jump out, and that can sound even worse than some mediocre diode hard-clip/distortion stage designs.
The way you pick your operating point is you draw a diagonal line from the plate voltage at the bottom to the saturation current on the left, and the output current moves along that line as the input signal changes (the input voltage is the voltage at the top of each curved black line). A good operating point is one where the intersections of the curves with the load line (the diagonal line you drew) are evenly spaced along the load line. If they are perfectly spaced, the amplification is exactly linear. As an example, if you plot a load line for 350V plate voltage and 2mA max plate current the intersections with the curves will be closer together on the right and move farther apart as you move left along the load line. That is the asymmetrical compression that gives a nice tube amp distortion tone.
If you do the same thing with a 12V plate voltage (and any plate current) you start running into that 0V grid curve and it's hard to reason about what's happening in between the two data points (curves) you have, because at some point the curves change and start looking like the 0V one, but it's hard to tell where. Once you start driving the grid positive the tube will stop conducting entirely and hard-clip your signal, which is what I was referring to before.
The TL;DR; would be something like look at how the 0V curve goes the opposite way as all the others, that's not where you want to be.
Under-voltage is only bad if the tube is designed for a high voltage and you don't give it what it is designed for. If the tube needs 200V, you give it 200V. If it needs 30V, give it 30V.
Some snobs will say that nothing which runs at only 30V will have the proper headroom.
... and then they drive their amp with chip-and-diode based overdrive pedal (e.g. Ibanez Tubescreamer), running on 9V, haha.
I agree with your first point entirely, but there is precedent in industry for putting starved-plate tube stages in things just for marketing.
A "great" component in a shitty design can sound worse than a "shitty" component in a great design. I just have a feeling that the marketing push to "Just put a tube in it" will lead to more of these "token" tube applications because it's cheaper to run it at whatever voltage rail is already there than putting some hulking transformer just to run a 300V B+ rail for a single preamp stage.
The headroom thing is all relative, I don't think your amp would be too happy if you fed it a 300V P-P signal from your 3kV Audiophile-Grade-Headroom pedalboard...
I also can't wait for the 64-bit digital audio revolution. Nothing with less than 384dB of dynamic range is worth listening to! /s
If you're only getting 384 dB out of 64 bits, you're doing it wrong by using integers. 64 bit double floats go from, what, around E-308 to E308 in the exponent. So that is around 616 Bels, or 6160 dB. :)
I find most cheap tube gear uninteresting, musically speaking. It's generally, as you note, a tiny low voltage 12AX7 preamp stage feeding a regular old transistor gain stage. There's a reason the old master volume Marshall amps are sought after, and why so many manufacturers have returned to all-tube designs.
Some of what goes on in audio is snake oil. In fact, a lot of it is. But, modeling amps and tube preamp stage gear still doesn't hold up well against a good tube amp. I bought a new amp a couple years ago, after having used the same amp for ~20 years (a 1984 JCM 800). I tried every amp in the small size range at two guitar stores. The clear winner was an all-tube Vox model. The modeling amps were way down the list, which was disappointing. I really believed we had the technology to replicate good amp tone (and some guitar amp sims on computer are reasonably good)...but we still aren't there.
And, the preamp tube with transistor volume stage amps were also clearly inferior to the master volume style all-tube amp I ended up buying.
Very nice write up and I'm in agreement. I've heard good things about Vox and their move back toward being the best consumer tube amp. I grew up with a 64 Fender Twin Silverface (Dad's gig amp) and it was a monster, just too much, but I'm glad we sold it to somebody who still has it. I became a solid-state guy but always lusted after the 5150 2x12" combo, and they're holding steady at about $500 used, so one of those is in my future.
I've used quite a few Line6 computer products and I like the bang-for-the-buck but would never, ever put them in the pro sound field. Fun to play with, cheaper than pedals, but takes me quite a bit in fiddling with settings + post production to make them worthwhile (same goes for my little MicroSpider amp, which is mostly for busking).
One thing that came across my radar was the Kemper, which seems to be that technological achievement you might have in mind. I've never played/heard one (that I know of), but I think it has a pretty good reputation thus far. Link: http://www.kemper-amps.com/profiling
I had a first generation 5150, as well, and loved it. Though when I down-sized it was the 5150 that got sold (while I kept the JCM 800). But, that was primarily a function of the size of the 5150 + 4x12" cabinet, while the JCM 800 was a 2x12" combo (which is clearly the ideal amp size for performance, though too big for recording); both amps were excellent. I consider it one of Peavey's crowning achievements, maybe the best thing they ever made. I haven't heard any of the new generation of them, once they stopped calling them 5150. They also moved most of their manufacturing out of the United States a few years back, which reportedly impacted quality...I don't know if the tube amps are still made in the US, or not.
Since I moved out of the motorhome (the reason I sold my JCM 800 and downsized to a tiny Vox was because I was living in ~200 square feet for four years, while traveling full-time), I've since bought another Marshall. It's a 50W JCM 2000 (I think...maybe 900) that I picked up for $600 (and a 4x12 cab that was a few hundred more), but it rarely gets used. The Vox sounds great and is right-sized for indoor use.
I'm really happy with my Vox, honestly; for most things it sounds as good as any amp I've ever owned, and I've owned some good as hell amps (I've also had some old Fenders). I wish it had a bigger speaker; a 10" would make it the perfect amp. It's got an 8", and sometimes low end stuff sounds pinched.
I was living in a motorhome, about 200 square feet, and traveling full-time. I held onto it for about a year, in the motorhome, but it just didn't make sense. I couldn't play it without being on the grid (too power hungry for the batteries), and had to move it every time I brought the slide in...and it was heavy as hell to be moving it around all the time. I sold it for a fair price, and once I settled into a fixed house again, I picked up another Marshall (a JCM 2000, this time, which is admittedly not in the same league as a six knob 800, but it's not a bad amp, at all). And, I have the little Vox, which is a great little amp. I play the Vox far more often than the Marshall, in fact.
I have owned a lot of classic gear over the years and have sold most of it. I view it as borrowing it from the universe rather than "owning it". If I buy it used, and I sell it for what I paid for it, or more, I find I have a healthier relationship with my things (I'm in charge, not the things). When moving into the motorhome, I sold a lot of great stuff. Antique furniture (my mom is an antique dealer, so my house was nicely furnished), synthesizers and guitars and amps, etc. The cost of keeping it was the cost of storing it, which would have added up to far more than its value over four years.
Anyway, these days, I have a good big amp (the JCM2000), a good little amp (the Vox AC4V), a good acoustic guitar (Gibson J45), a good electric guitar (Schecter from when Schecter made really good guitars by hand in California), a good bass (G&L L2000), and a good drum set (Roland TD4S). That's my minimum for musical happiness, and I try not to keep anything else, even if I acquire stuff temporarily to play with it.
Too bad where I live we can't buy good used gear. Nothing good ever comes by, people hoard and hold on to it for their lives, and when it does come by, it's overpriced to the point it justifies buying new.
99% of the stuff sold in stores it is cheap generic clones of Fenders (MOSFET amps and Stratos).
That would be hard. I live in Austin, TX, which is where half the broke musicians in the world live (and a number of famous ones). So, lots of really good stuff comes onto the used market here, and used gear sells fast, if it is priced fairly. So I can buy and sell good gear as often as I want, and my standards for what I buy can be quite high.
Why is early in the gain chain necessarily bad? Suppose the later stages of the chain introduce no distortion, would it be possible (in theory) to have low power devices like this create all the nonlinear effects considered desirable by audiophiles and then just amplify that later on?
That is nonsense. Headroom is inversely proportional to how much distortion you are getting, no matter where in the signal chain. A metal tone has very little headroom. You can't add headroom to it without gating tricks: measuring the level of the pre-distorted signal, and using that to control the volume of the distorted signal.
Headroom is bad anyway. The electric guitar has way too much dynamic range to be useful. For clean guitar, your best friend is compression, so that you don't disappear in the mix against other instruments when you articulate some passage of notes softly.
Of course, that's how it's done. Thus distortion is just an effect and not amplification. You can put a gain of thousands. The resulting may be swinging close to rail-to-rail (relative to the distortion effect's power supply). This is too much for the next thing in the chain, so it is turned down. No brainer.
To clarify what I meant about headroom, I was specifically talking about headroom before the circuit starts to clip/break up/etc.
e.g. If you have a diode clipping OD/Distortion circuit made out of some diodes with a Vf of 5mV as opposed to the 700mV of a normal diode, you would need to have a smaller input signal for an equivalent amount of distortion. That smaller signal has a lower SNR given some constant noise floor from thermal noise etc, and the SNR can only stay the same or get worse after you start amplifying it.
That is well and good, but pointless. People use such a circuit to get a heavier distortion with the same input signal, not to get light distortion with a smaller signal.
Let's put it this way: if you have high gain metal distortion circuit gained up to a 5mV clipping threshold, and then you roll down your guitar volume knob to play the blues, you're kinda using it wrong.
It's pointless in the case that you mention, where you're going for a hard clipped metal distortion tone. I was envisioning more of an overdrive sort of application where hitting the rails is NOT the desired effect. The 5mV hard clipper was an extreme example, but you could conceivably use it for soft overdrive/compression with a small enough input signal which was what I had in mind.
If hitting the rails is not desired, then don't configure the effect to have so much gain.
The point still stands that you can get the distortion effect, at the desired amount, at various places in the signal chain.
The problem you're talking about is about using too weak a signal and then using make-up gain. That can also happen anywhere in the chain.
I can reproduce the problem without distortion at all, using a clean signal chain.
Repro 1: turn down the guitar volume to simulate an extremely weak pickup. Then turn up the input gain to compensate. Result: noticeable increase in noise.
Repro 2: turn down pre-amp volume, and crank up power amplifier volume to compensate. Result: noticeable increase in noise.
Gains/levels have to be evenly distributed in the chain.
Sure, you will lose headroom if your intent is to have some soft distortion from the back-end of the amplifier, but you put a heavier distortion earlier in the signal chain. The heavy distortion masks the later one; it evens out the level so the headroom from the back is not available. There is a fix for that: you can punch that distortion in and out with your foot as needed.
are SNR issues like that and the headroom an issue for a guitar amp? I mean why couldn't the solid state part be designed conservatively with extra headroom? Or do the desirable distortion products make that difficult even with a conservative design in later stages?
Generally you want to avoid noise early on in the gain chain just because it gets amplified later on. Headroom is entirely relative, you just need to design your gain stages such that the power amp isn't railing when you turn your guitar up halfway.
I see. Intersting. How do you think about the desirable distortion characteristics vs bad "noise"? Is there an industry standard definition for guitar amps?
Seems like the bad noise in the case we're discussing would be what the tube circuit generated when it was not being intentionally driven to distortion... is that a correct interpretation?
Noise would be thermal noise generated in circuit components, or mains hum, anything that is there when you aren't playing any notes. I wasn't spraking exclusively about guitar amps, all this applies to analog electronics in general.
Noise is anything that is still present when you take away the desired input signal, excluding deliberate time-based effects like reverbs and delays.
Frequency components that are not in the original signal, but are only present when the signal is there are usually distortion.
(Why "usually": radio-frequency interference is noise. In audio, you may not notice RF when there is no signal. But when signal is present, it may mix with RF in a nonlinear way, causing additional distortion products attributable to the RF. I.e. the RF noise is "descends" into the signal's frequency range via intermodulation.)
If you want to avoid noise early in the gain chain, do not rob your guitar of signal by attenuating the output of the pickups with the guitar's volume. Now though that is done, by some players (and works for them), it isn't a way to get headroom or minimize noise.
You get the least amount of noise by keeping the volume of the guitar at maximum, and switching tones later in the chain. A clean pre-amp channel has much better noise characteristics than a dirty channel, and rolled down guitar volume control.
The point I was making about turning the guitar up halfway was that you need to design amplifier gain stages so that there is not so much gain that the amplifier hits the rails with a reasonable input signal. E.g. If your preamp stage has a voltage gain of 100 and your expected input signal is 1v p-p but you only have +/-20v rails for the power amp stage, you objectively don't have enough headroom.
Based on that article, I'm not convinced that it's the best that the part could do, based on the circuit schematic. We would not be using the windings of a transformer as a load in a typical gain stage in a musical instrument preamp. A typical inverting stage would have a large-ish resistor as its load, in parallel with the fairly high impedance of the next stage (another tube circuit that is similar).
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[ 2.4 ms ] story [ 160 ms ] threadhttp://spectrum.ieee.org/semiconductors/devices/introducing-...
Could be the next big thing in computing. Or not. Only time will tell.
From the photo, it looks like that may be the case: what are those green squares? The form factor is like that of a VFD.
It is quite suggestive of the intent that the part will be mounted such that it is visible through a display window in the equipment's case.
Korg has previously released synthesizers and a sampler using vacuum tubes for effect rather than to make them "better" in any objective sense.
This makes them almost instruments in their own right. When playing a guitar through heavy tube distortion, the tubes react to your playing very sensitively, just like the guitar itself does.
When people describe random pieces of electronic equipment as "musical" this is usually what they mean.
This applies to IC amps as well, but not to the same extent. The recent history of music tech is a story of working hard with esoteric techniques to produce amazing music from primitive gear in the 60s and 70s, then inventing more reliable and repeatable techniques using digital technology in the 80s and 90s.
In recent years, people are realising that the man-vs-machine-vs-physics attrition of the mid to late 20th century actually led to a certain sonic complexity that has been missing in recent years. So now we see these hybrid products which merge old and new technology to get a deep sound while retaining reliability and a good workflow.
See also: analog voltage controlled oscillators which automatically tune themselves using digital clocks, and compensate for temerature changes.
(Incidentally, a lot of audiophile nonsense stems from them making category errors between their puported search for crystal clear reproduction, and studio engineers' quest for signal distortion with emotional quality. This is similar to how MBA types cargo cult programming terminology.)
So I agree that there isn't much ICs can't emulate but I also think it can be difficult to write a good emulation program.
Also interesting will be to hear how they actually sound. All tubes aren't built equal, and even with traditional tubes you can find people arguing about the merits of the 6L6 or EL-34.
Of course, if this thing delivers on both fronts that would be incredible. Tubes are in short supply, and my friends who play on tube amps are always complaining out how expensive it is to replace the damn things.
(at least that's my guess)
Also, I notice they list Petrucci as an artist. I had a look on stage at his rig last tour (fortunate to do so, was I) and I am sure it was entirely Mesa Rectifier MIDI enabled preamps and Mesa Simul-Class2:Ninety rigs for the amplification, ran to two small 12" (or 10") cabs miked up offstage (so less bleed from live drums, more control over the sound) so I am curious where he actually uses this in his signal chain? I doubt he actually uses it for anything other than effects??? Same for Myung - he was using a DI box and a Demeter power amp ran on a dummy load for overdrive. (I chatted with the bass tech, friendly guy! The entire crew were friendly!)
From what I've seen on youtube of setup run throughs, people almost always have a complete non-fractal set of equipment for backup, but an axe-fx patch can actually contain all of this equipment. Manufacturers even sell their own racks that can be loaded into axe-fx.
Can't find any more recent info. Pretty sure Petrucci does the same thing, with Axe-Fx as effects processor rather than amp modeler. Don't know about Metallica.
There are quite a few artists who do use the Axe-Fx or Kemper live in lieu of amps though: Animals as Leaders, Periphery, Paul Masvidal from Cynic, Devin Townsend (sometimes, he seems to switch back and forth a lot), Jeff Loomis in Arch Enemy uses a Kemper live (https://www.youtube.com/watch?v=J92RP-fFO_g). Plus quite a few lesser known musicians. If you have an Axe-Fx, you can do a fly-in gig with it and have a consistent sound without being at the mercy of whatever crappy backline the venue has. Handy tool for a guitarist for hire.
Especially in metal though, there's a certain showmanship aspect to having a bunch of big loud amps on stage. A lot of the bigger bands for years have even lined stages with dummy stacks of 4x12 cabinets just for show. So even if they start using a modeler, they probably won't make a big deal of it. Smaller bands, playing in smaller venues run into the problem of stage monitoring. You can run your Axe-Fx into front-of-house and probably get a good sound to the crowd, but a lot of the smaller venues have lousy monitoring setups on stage and guitarists are used to essentially using their amp to compensate for that. So you might still want a power amp and cabinet on stage in that case.
Anyway, I have an Axe-Fx II and it's replaced all my tube gear. I wouldn't say it sounds 100% the same, but it's really close. Beyond the sound, what it does that other modelers have not done so well is get the "feel" of playing through a tube amp. The really subtle dynamics and compression that you don't necessarily hear but that affect how you play when your ears and hands are reacting to what the amp does. Leaps and bounds better than Line6 or Podfarm. And at apartment-safe volume levels, I'd even argue that it sounds better than most tube amps, so that's a huge plus for me.
Even the guitar amp simulators in apps like Logic Pro X sound pretty ropey. My friend (who is an excellent guitarist and teaches many many people) struggled to get a good sound out of it, and I really did as guitar amps are completely alien to me (why a presence control eh? why not just leave it on 10 and let the treble do the job???). To be fair to the developers of the software based ones, they make a good attempt but amp simulators never ever sound like the real things.
In my defence I used to use them for a while as a bass player but now am entirely analogue, with real glowing warm things in my gear. The difference is like chalk and cheese. I confess I always valves in the preamp stages - I do have one that uses an EL84 (normally a power amp valve) in the preamp stage combined with a 12AX7 for a great round sound; I used class D for the power amp because I don't want my back to break carrying gear). I have played for 20+ years and my ability these nuances has improved, so I wouldn't have heard the difference to begin with, that's for sure. Pity my ears have been subjected to drummers in that time, or I would hear the differences far better!
The hardware valve sound is a mix of compression, microphony, and at least two different kinds of distortion - and probably other things no one has figured out yet.
Distortion is unexpectedly complicated on its own. A while back I looked into models that use a Volterra series, and the math soon got very scary.
Doing it properly could potentially be a machine learning problem. I seriously doubt it's possible to reduce good distortion to a simple one-line equation - even a very long one with lots of coeffs.
But it's confusing: There is already a model of tube called 6P1 (1).
Anyway, who is this for? Engineers/instrument designers? Korg to use internally?
(1) http://en.wikipedia.org/wiki/6P1P
This is an important question. I doubt I'll have the chance to use this unless someone in Asia makes a knock off.
Also, when tubes were in their heyday, there existed miniature tubes: perhaps not as small as this new one, but a lot smaller than a 12AX7/ECC83.
Check out the vacuum tube hearing aid pages in the Hearing Aid Museum:
http://www.hearingaidmuseum.com/
Can't believe they made kids wear such things. :)
Looks like you could possibly just use those things as distortion elements.
From the picture it looks like this part is a dual triode device. The groups of three pins on either side are the anode/grid/cathode, and the four pins in the middle are separate filament circuits. 12AX7 and similar tubes usually have only three pins for two filaments: the filaments are in series with a center tap for hooking them up in parallel.
If this thing is similar to VFD's, it can probably run at around 20V for the anode voltage, and a small voltage for the filaments, around 2V.
It would be interesting to develop a tube board for the ADA MP-1 guitar pre-amp with these things. The stock one uses a pair of 12AX7's. A 9V power feed is used for the filaments, and 190V for the anode voltage. That could all be gutted out, and a simpler transformer used which doesn't provide a high voltage tap. The silicon side of the MP-1 runs on +/-15V rails; the same underlying transformer tap could could power the Noritake tubes.
this 1940 vacuum tube hearing aid used a bone-conducting transducer scheme.[1] I was stuck thinking that was a fairly new concept (at least from the 80s) for military comms, and was intrigued by the use of such tech in the recent Google Glass.
It's cool to see that the idea was much older than I realized.
[1]: http://www.hearingaidmuseum.com/gallery/Vacuum%20Tube/Acoust...
With the low operating range and low bias point you don't get the same effect as you do with a tube biased to it's sweet spot. It seems like a marketing gimmick like the starved-plate 12ax7 stage they put in everything nowadays (with ~12V B+ as opposed to the 250-400V B+ you find in nearly all classic amp designs), along with a few LEDs and a window in front so you can see where your extra $100 is going.
If you plot (really any) load line on the plate curves for a 12AX7 with a < 50V B+ you're in a really poor, highly non-linear region. Looking at plate curves for some old VFD tubes the operating range for those is way down in the same region in the lower left corner if you plot them over the 12AX7 plate curves.
Given the size and the fact that it uses 2% of the power of conventional tubes, I doubt that these tubes could be used as an output stage. I would have to guess that they're running them cold as well. Preamp tube power draw is often dominated by the heaters
Of course this is all speculation until they publish a datasheet...
When you run a low plate voltage you start to run into some of the undesirable things that happen when you get close to the point where the tube stops conducting entirely. you start to hard-clip the signal on one half-cycle and all those odd square-wave harmonics start to jump out, and that can sound even worse than some mediocre diode hard-clip/distortion stage designs.
EDIT: If you look at the plate curves for e.g. a 12AX7 http://www.paleoelectronics.com/blog/wp-content/uploads/2009...
The way you pick your operating point is you draw a diagonal line from the plate voltage at the bottom to the saturation current on the left, and the output current moves along that line as the input signal changes (the input voltage is the voltage at the top of each curved black line). A good operating point is one where the intersections of the curves with the load line (the diagonal line you drew) are evenly spaced along the load line. If they are perfectly spaced, the amplification is exactly linear. As an example, if you plot a load line for 350V plate voltage and 2mA max plate current the intersections with the curves will be closer together on the right and move farther apart as you move left along the load line. That is the asymmetrical compression that gives a nice tube amp distortion tone.
If you do the same thing with a 12V plate voltage (and any plate current) you start running into that 0V grid curve and it's hard to reason about what's happening in between the two data points (curves) you have, because at some point the curves change and start looking like the 0V one, but it's hard to tell where. Once you start driving the grid positive the tube will stop conducting entirely and hard-clip your signal, which is what I was referring to before.
The TL;DR; would be something like look at how the 0V curve goes the opposite way as all the others, that's not where you want to be.
Some snobs will say that nothing which runs at only 30V will have the proper headroom.
... and then they drive their amp with chip-and-diode based overdrive pedal (e.g. Ibanez Tubescreamer), running on 9V, haha.
A "great" component in a shitty design can sound worse than a "shitty" component in a great design. I just have a feeling that the marketing push to "Just put a tube in it" will lead to more of these "token" tube applications because it's cheaper to run it at whatever voltage rail is already there than putting some hulking transformer just to run a 300V B+ rail for a single preamp stage.
The headroom thing is all relative, I don't think your amp would be too happy if you fed it a 300V P-P signal from your 3kV Audiophile-Grade-Headroom pedalboard...
I also can't wait for the 64-bit digital audio revolution. Nothing with less than 384dB of dynamic range is worth listening to! /s
Some of what goes on in audio is snake oil. In fact, a lot of it is. But, modeling amps and tube preamp stage gear still doesn't hold up well against a good tube amp. I bought a new amp a couple years ago, after having used the same amp for ~20 years (a 1984 JCM 800). I tried every amp in the small size range at two guitar stores. The clear winner was an all-tube Vox model. The modeling amps were way down the list, which was disappointing. I really believed we had the technology to replicate good amp tone (and some guitar amp sims on computer are reasonably good)...but we still aren't there.
And, the preamp tube with transistor volume stage amps were also clearly inferior to the master volume style all-tube amp I ended up buying.
I've used quite a few Line6 computer products and I like the bang-for-the-buck but would never, ever put them in the pro sound field. Fun to play with, cheaper than pedals, but takes me quite a bit in fiddling with settings + post production to make them worthwhile (same goes for my little MicroSpider amp, which is mostly for busking).
One thing that came across my radar was the Kemper, which seems to be that technological achievement you might have in mind. I've never played/heard one (that I know of), but I think it has a pretty good reputation thus far. Link: http://www.kemper-amps.com/profiling
Since I moved out of the motorhome (the reason I sold my JCM 800 and downsized to a tiny Vox was because I was living in ~200 square feet for four years, while traveling full-time), I've since bought another Marshall. It's a 50W JCM 2000 (I think...maybe 900) that I picked up for $600 (and a 4x12 cab that was a few hundred more), but it rarely gets used. The Vox sounds great and is right-sized for indoor use.
I'm really happy with my Vox, honestly; for most things it sounds as good as any amp I've ever owned, and I've owned some good as hell amps (I've also had some old Fenders). I wish it had a bigger speaker; a 10" would make it the perfect amp. It's got an 8", and sometimes low end stuff sounds pinched.
I have owned a lot of classic gear over the years and have sold most of it. I view it as borrowing it from the universe rather than "owning it". If I buy it used, and I sell it for what I paid for it, or more, I find I have a healthier relationship with my things (I'm in charge, not the things). When moving into the motorhome, I sold a lot of great stuff. Antique furniture (my mom is an antique dealer, so my house was nicely furnished), synthesizers and guitars and amps, etc. The cost of keeping it was the cost of storing it, which would have added up to far more than its value over four years.
Anyway, these days, I have a good big amp (the JCM2000), a good little amp (the Vox AC4V), a good acoustic guitar (Gibson J45), a good electric guitar (Schecter from when Schecter made really good guitars by hand in California), a good bass (G&L L2000), and a good drum set (Roland TD4S). That's my minimum for musical happiness, and I try not to keep anything else, even if I acquire stuff temporarily to play with it.
Good attitude towards life.
Too bad where I live we can't buy good used gear. Nothing good ever comes by, people hoard and hold on to it for their lives, and when it does come by, it's overpriced to the point it justifies buying new.
99% of the stuff sold in stores it is cheap generic clones of Fenders (MOSFET amps and Stratos).
Headroom is bad anyway. The electric guitar has way too much dynamic range to be useful. For clean guitar, your best friend is compression, so that you don't disappear in the mix against other instruments when you articulate some passage of notes softly.
e.g. If you have a diode clipping OD/Distortion circuit made out of some diodes with a Vf of 5mV as opposed to the 700mV of a normal diode, you would need to have a smaller input signal for an equivalent amount of distortion. That smaller signal has a lower SNR given some constant noise floor from thermal noise etc, and the SNR can only stay the same or get worse after you start amplifying it.
Let's put it this way: if you have high gain metal distortion circuit gained up to a 5mV clipping threshold, and then you roll down your guitar volume knob to play the blues, you're kinda using it wrong.
The point still stands that you can get the distortion effect, at the desired amount, at various places in the signal chain.
The problem you're talking about is about using too weak a signal and then using make-up gain. That can also happen anywhere in the chain.
I can reproduce the problem without distortion at all, using a clean signal chain.
Repro 1: turn down the guitar volume to simulate an extremely weak pickup. Then turn up the input gain to compensate. Result: noticeable increase in noise.
Repro 2: turn down pre-amp volume, and crank up power amplifier volume to compensate. Result: noticeable increase in noise.
Gains/levels have to be evenly distributed in the chain.
Sure, you will lose headroom if your intent is to have some soft distortion from the back-end of the amplifier, but you put a heavier distortion earlier in the signal chain. The heavy distortion masks the later one; it evens out the level so the headroom from the back is not available. There is a fix for that: you can punch that distortion in and out with your foot as needed.
Seems like the bad noise in the case we're discussing would be what the tube circuit generated when it was not being intentionally driven to distortion... is that a correct interpretation?
Frequency components that are not in the original signal, but are only present when the signal is there are usually distortion.
(Why "usually": radio-frequency interference is noise. In audio, you may not notice RF when there is no signal. But when signal is present, it may mix with RF in a nonlinear way, causing additional distortion products attributable to the RF. I.e. the RF noise is "descends" into the signal's frequency range via intermodulation.)
- avoid noise early on in the change
- turn your guitar up halfway
If you want to avoid noise early in the gain chain, do not rob your guitar of signal by attenuating the output of the pickups with the guitar's volume. Now though that is done, by some players (and works for them), it isn't a way to get headroom or minimize noise.
You get the least amount of noise by keeping the volume of the guitar at maximum, and switching tones later in the chain. A clean pre-amp channel has much better noise characteristics than a dirty channel, and rolled down guitar volume control.