Get off my lawn.

Tuesday, January 20, 2009

Another amp joins the family

...or should I say, "the fleet." Although I only own a couple of guitars of each type (electric, acoustic, bass), I've managed to amass a sizable pile of amplifiers over the past decade, along with another pile of things that merely sound like amplifiers.

So far, the list includes:

  • Tech21 Trademark 60
  • Tech21 Tri-AC
  • Tech21 GT2
  • Tech21 PSA-1
  • Boss GX-700
  • Rocktron Pirhana
  • Vox AC-1

I should get them all together for a picture sometime.

In case you hadn't noticed, I'm kind of a fan of Tech21 gear. Each of the Tech21 products listed above is useful for something, and has a sound of its own. They all sound good on recordings, and are pretty versatile. The Boss GX-700 is good for super-clean or heavily-effected sounds. The Rocktron Pirhana is really well-built, and useful for 1 thing: Smashing walnuts. It's in storage, as I buy my walnuts pre-hulled.

Notice that none of these is a "modeling" amp (except the GX-700, and that's debatable). Modeling amps digitize your guitar's signal and run it through a software simulation of a desirable guitar amp. Then the signal is sent to a power amp, and on to the speakers.

I've never been a fan. First of all, for something as wild and woolly as a guitar amp is supposed to be, the idea of digitizing the signal and sending it through a computer seems cold and clinical. It's about as much fun to play through as it sounds like it is. Modeling amps usually sound pretty credible, but playing through them is nothing like playing through a real guitar amp. It's more like playing a recording of a guitar amp. It's like the difference between being chased by a charging rhino, and watching a guy being chased by a rhino on TV. The former is exciting and motivational, the latter, not so much. I also notice a latency in modeling amps that's pretty annoying. With some, I would swear it's a good 30ms between the time I play a note and when the note comes out of the amp. It's not enough to make it hard to play in time or anything like that, but it's enough to make the amp feel sluggish. You feel like you're always pushing things uphill. Overall, playing through one just isn't a very musical-sounding experience. At best, you can aspire to imitate someone by playing through an amp that sounds like theirs. But it's not the kind of thing that inspires creativity.

It's a total contrast to the way a good tube amp works. Notes jump out of a good tube amp in a startling way. A good tube amp is very responsive. If you play softly, it calms down and sounds clean. If you play hard, it gets more aggressive sounding. Everything you do with your hands has an immediate effect on the sound. So as much as the sound, it's the "feel" of good tube amps that makes them so popular with guitar players, I think. It's inspiring to play through one.

There's something else a good tube amp does that I have noticed, but haven't been able to really describe. It's hard to explain, but under some conditions, it's like the physical sensation of the strings under your fingers changes when you're playing through one. They seem to become kind of rubbery, and playing becomes really easy. Obviously, the strings don't take on new physical properties when a tube amp is involved, but something about the way the notes come out of the amp makes the act of playing those notes feel different than it does when playing through a solid-state amp. It's almost like the amp knows what you're going to play before you play it. Not all tube amps do it, but when you encounter one that does, you'll remember it, and you're basically spoiled for playing through anything else. You just want to keep playing and playing and playing. You feel like you can play better than normal. And to verify that you haven't suddenly turned into a better musician, you can just unplug the guitar and plug it into a solid-state or modeling amp in the same room, and play through it. It will feel as stiff and lifeless as a piece of plywood, most likely. I've tried it.

It seems like a stupid thing, but I know it's not just me. Terms like "sponginess", "push back", "bloom" and other inadequate terms have been invented to try to describe the sensation in numerous articles I've read on the subject. The effect I'm talking about is most pronounced when playing with a really distorted or overdriven sound. Having experienced it, I think I understand why so many rock guitar players grow their hair long and have a weird expression on their face when they play. It's the amp. I can prove that what I'm saying is true simply by referring you to any video featuring Peter Frampton playing an acoustic guitar. In those videos, notice that he looks like just a normal guy playing a guitar. Make a mental note of his facial expression. Now, find a video of him playing a solo on an electric guitar. Notice the change in his expression. His mouth is contorted into all kinds of strange shapes. At first you think, "The poor guy is choking on something, or getting ready to hurl." But those facial expressions are actually what it looks like when Peter Frampton is being pleasured by a guitar amp.

None of my amps do that. Except for the Rocktron Pirhana, they're all solid-state. The Tech21 pieces sound authentic enough. But the feel isn't the same. It's not the mere presence of tubes that makes it happen. Of my amps, the Tech21 pieces most "tube-like" in the way they sound, and in the way that they play. The closest thing to a tube in a piece of Tech21 gear is a MOSFET. My Rocktron generates its distortion through tubes exclusively, but they're preamp tubes, in a preamp. There's nothing there in the way of a tube amp driving a speaker, or a simulation thereof. So the feel is as lifeless and stiff as a crappy solid-state amp from Sears. It doesn't do anything that an $80 stompbox can't do. It's a total bore to play through.

The squishy feeling you get from a tube amp comes in part from the power tubes not being able to keep up with the work they have to do. They're trying to amplify their input signal, and they can't keep up, so the output gets compressed, clipped, distorted, and so on. The speaker's voice coil generates current that feeds back into the amp and causes weird things to happen. All kinds of subtle things go on that have a cool effect on the sound and feel of the amp. One way to make it happen is to turn a tube amp up really loud, which is impractical for most applications. I had a 33-watt tube amp once, and the thing was LOUD. I put a wall of cardboard boxes in front of it once to muffle the sound, and it just knocked them out of the way. Pete Townsend used to play in front of a wall of 100-watt Marshalls. No wonder he's deaf.

So, about the new amp. It's a Vox VT30 Valvetronix. My wife couldn't decide what to get me for Christmas this year. I was in a music store and saw the amp sitting there. I had never played through one, but for some reason, I suggested she get me that. (I still like getting toys for Christmas, even though I'm supposed to be a grown-up.)

It's a modeling amp, with 22 different amp models. There's the obvious selection of Vox amps, including an AC-15, a couple of AC-30s, an AC50, and a "Brian May" amp, which sounds exactly like the guitar sound on "Tie your Mother Down." It also has a couple of Dumble models, 3 or 4 Marshalls, some Fenders, something called "Metal Bull", a Peavey 5150, a Mesa Rectifier, an Engl, and another one modelled on a $25K custom-made amp, called "Express Train." I don't know what amp it's trying to emulate.

Aside from the "amp" knob, it has the standard complement of knobs: Gain, Volume, Treble, Mid, Bass, Reverb, and Master. On the back, it also has a "power level" knob. This is handy, because it lets you control how much power the amp actually sends to the speaker. Full up, it's 30 watts, which is way too loud for my office, but about right when you're jamming with a drummer. All the way down, it's 0.5 watts, which is about as loud as someone whispering.

Somewhere between the output of the modeling section and the power amp, there's a little tube-based power amp running a 12AX7 preamp tube.

It's an ingenious idea, and it's not new. The ADA Ampulator did the same thing 12 years ago. The idea behind using a preamp tube to do a power tube's job is that it doesn't really amplify the signal to a level sufficient to drive a speaker. It stays at line level, suitable for input to a solid-state power amp. The nice thing about this is that you can crank the amp by turning the Master volume knob up, but keep the amp quiet by limiting the power output. So you get some of the same benefits of a cranked amp, without the wall-toppling volume.

So, it's a modeling amp. It generates its sound through a computer. But wow. I am impressed. The models are pretty good. The Dumble ones sound great. The Vox ones sound great. All of them do really, except for the "Express Train" one. If I paid $25K for an amp that sounded like that, I'd feel pretty stupid. (Especially now, knowing I could get the same sound for $200 along with 21 other amps that sound better.)

As far as the feel, I'd have to say it's got at least part of it. There's no latency that I can tell. It's not sluggish. You can get a really distorted sound with the guitar's volume all the way up, then turn it down, and the sound is clean. The distortion isn't harsh-sounding, even on the most aggressive models (5150, Engl, etc). To my knowledge, it hasn't caused my face to contort into something awful to look at, although I am thinking about cancelling my upcoming haircut. It's only a small amp. If I had a wall of them or something, I would have already turned into Dimebag Darrell.

Quality-wise, I don't think I'll be cracking walnuts with it. It seems kind of fragile. When I was in Jr. high, I found a piece of steel grating that I made a speaker grill out of for an amp I had then. My installation more professional than the grill on the front of this amp. The input jack looks like it's probably going to break at some point. But when it poops out, I'll probably buy another one.


  • At 6:31 PM , Blogger Christine P. said...

    I've got an old Fender Princeton tube amp, as well as a Vox AC-1 (what a cute little thing and incredibly handy during a power failure) and a Roland Micro Cube (modeling amp; pretty fun). I can say for sure that the tube amp has a completely different *smell* from the solid state amps. I don't know what it is about that smell... Anyways, I've never noticed any latency from the Micro Cube. I've also got a Zoom GM-200 (amp modeler) and never noticed any latency while using that, either. Guess I'm fortunate to have gotten to modelers so far along in the evolution of the technology or I might have passed on the Zoom and the Roland when I had a chance to get them at a discount.

  • At 6:57 PM , Blogger Kelly said...

    I think the smell comes from the parts baking inside the amp. It's a good smell! I had a Carvin V33 once that put off a nice smell.


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