What Is the Boss Waza Tube Amp Expander?

Game Changer

Remember when the iPhone came out? Do you remember what made it so great? There are a lot of solid candidate reasons for why. One, it had that signature Apple industrial design that embraced simplicity, abandoning all the hardware dialing buttons for a beautiful, high-resolution screen that covered almost the entire face of the device. It had a snazzy multi-touch user interface and an accelerometer that allowed the software to respond to the physical orientation of the device. It had a bunch of useful apps that made the previous carrier-provided apps look like the poorly-conceived, slapdash efforts that they usually were.

But I'd argue the most compelling thing the iPhone had was massive convergence. It put a mobile phone, PDA, watch, MP3 player, camera, text messenger, GPS, maps, web browser, and an open (relatively speaking) computer software platform all in one small device. It obsoleted, or at least seriously upended, the previously accepted standards for all of those products within just a couple of years.

I think I've encountered another convergence device. This time in the world of guitar. Lest I over-hype it, I should say that it's not nearly as revolutionary as the iPhone. But it is a very compelling device for its audience. And I hope it shakes things up in its little segment of the MI industry. Like the iPhone, it converges a bunch of capabilities that, when you think about it, belong together. And like the iPhone, you might not instantly appreciate it until you ponder its capabilities and the overall gestalt becomes clear.

I'm talking about the Boss WAZA Tube Amp Expander.

I'm not going to review it. The definitive review for the TAE has already been written as far as I'm concerned. (Spoiler alert: It kicks ass.) But I am going to write about it here because I think it's a remarkable product.

What is the TAE? At a very abstract level, the TAE augments your amp with capabilities that make it a gigging and recording power house. Calling it a "Tube Amp Expander" is actually quite accurate. Functionally, if you look at it in terms of its closest competitors, you might think it's just another load box and hardware IR host. But that description is woefully inadequate because it has a ton of other features that add up to something far more interesting in my opinion. 

Problem Solver

So let's define it in terms of the myriad problems that it solves. If you're a gigging or recording musician that uses tube amps – particularly vintage-style tube amps – you're going to recognize these problems:
Getting a good, cranked amp sound at lower volume
I've been a long-time user of resistive attenuators for knocking down the volume of a raging tube amp. A typical attenuator lowers your amp's volume by converting some portion of its power to heat and powering the speaker with what's left over. They can work pretty well, but only up to a point – if you attenuate too much, they start to sound kind of crappy. The TAE takes a different and better approach. The TAE uses a reactive load to bring your speaker output all the way down to line level converting all the power into heat. Then it amplifies that line level signal using a built-in 100 watt power amp to drive your speaker cabinet. As with a traditional attenuator, this approach allows your amp to be cranked up for improved sound, but it has a couple of significant advantages. First, reactive loads simply sound a lot better than resistive load attenuators. Second, the reactive load in the TAE has a new trick up its sleeve. It has a user-configurable impedance curve to fine tune the load to more accurately imitate the cabinet your amp thinks it's connected to. That's a long way of saying that, set correctly, it will make your amp feel and sound more like it's supposed to. Finally, by bringing it down to line level and then amplifying it with another power amp, it enables the TAE to do a lot of other useful things with the signal which I'll get to.

Using a small amp on a big stage
I used to have a tiny 1x10 practice amp that I would do small club gigs with because it was super portable and its funky lo-fi sound (it had a woefully under-spec'd output transformer) worked for the swing/jump-blues we were doing. I also liked it because I could wind it up, but the volume wouldn't overwhelm the small clubs I was playing. I remember once showing up for a gig and finding out that we were slated to play on the rooftop patio of the club. My little amp just didn't have the power to play what was essentially an outdoor gig and diming the volume turned the sound to mush because of its puny output transformer. With the TAE however, it wouldn't have been an issue because the built-in 100W power amp effectively makes any small amp a hell of a lot bigger.  I could have ran the amp at its normal volume setting through the reactive load and turned up the TAE's power amp to just make that sound a lot louder.

Playing on a no-volume stage
Ever done a gig with no backline and everybody plays direct into the board (except perhaps the drummer)? I have not. But that’s the standard for big production acts to declutter the stage and control the mix, and it’s getting more and more common at smaller venues. Well, the TAE allows you to go direct with your beloved 100W fire-breathing, bowel-rearranging, vacuum tube dinosaur. You simply run your amp into the TAE, and it will absorb the power and output a line-level signal to the FOH mix either instead of, or in parallel with, the built-in 100W power amp output. It can even give the FOH a stereo mix with effects (which I'll talk about in a moment).

Easily getting a good miked amp sound on stage
Have you ever had a really glorious sound coming from your amp, then you get out in front of the PA mains and what you hear from the PA sounds nothing like the sound coming from your amp? That's because getting a good miked amp sound can be a lot more complicated than shoving an SM57 in its grill. The TAE dispels all the black art and makes it very easy to provide a killer sound to FOH. Before that line-level output is sent to FOH, the TAE will first send it through an impulse response (IR) based speaker cabinet simulator to make it sound like it's driving a real speaker cabinet properly miked with a good microphone. IR-based cab/mic simulations are incredibly authentic sounding. The TAE comes with 22 mic’d cabinet emulations, 9 close mic types, and 5 room mic options. You can even import 32 of your own custom IRs, which can be purchased from vendors online or you can record your own if have the equipment and know what you're doing.

Easily getting a good miked amp sound in the studio
That line-level signal of your guitar amp feeding an expertly miked, high quality speaker cabinet can feed a recording studio mixer just as well as a it can the FOH mixer. Or you can bypass the mixer altogether because the TAE has a built-in computer audio interface for sending the digital version directly to your DAW.

Listening to your amp via headphones
The TAE can also take that speaker cab simulated output and route it to its built-in headphone jack, effectively turning your prized vintage plexi Marshall into the world's most expensive headphone practice amp.

Adding master volume to an amp that doesn’t have one
Instead of butchering your vintage amp by adding a master volume, the TAE's reactive load and built-in power amp effectively add a master volume to any amplifier. And pretty much the best-sounding master volume you'll ever hear too because your entire amp will still be turned up loud, even though your speaker cabinet won't know it. The TAE can even auto-compensate for the effects of Fletcher Munson curve.

Adding reverb to an amp that doesn’t have it
Remember I said that bringing your amp output down to line level enabled the TAE to do great things with it? Well, this is one of them. It has built-in digital reverb, with hall, room, plate, and spring emulations. And unlike plugging a reverb pedal into the amp input, this reverb is applied to your signal post-distortion, which is the best and most natural sounding way.

Adding an FX loop to an amp that doesn’t have one
The TAE also has an effects loop that allows you to run your post-distortion signal through whatever effects you want. The loop is switchable between -10 and +4 db level so it supports both rack and pedal effects, and it can be configured for series or parallel operation. This is so handy! Time-based effects – reverb, delay, modulation – sound much, much better placed after any distortion producing components. If you've ever run a delay or reverb pedal into the front of an overdriven amp, you know what I'm talking about. In fact, it's actually better than a typical amp effects loop because it's after the entire amp (power tubes produce overdrive too) instead of just the preamp.

Adding basic effects
But you might not even need the effects loop because the TAE comes with the bread-and-butter effects built-in including delay, EQ, compression, and the aforementioned reverb. For me, this is close to ideal as these are pretty much the effects I use most with guitar. If it had modulation effects it would be complete, but with all the other goodies the TAE provides, plus an effects loop that you insert anything you want into, that's a very minor complaint.

Adding additional stage capabilities to amps that don’t have them
As a player that generally gravitates to vintage-style amps, one of the things I miss out on are all the cool convenience features of modern amps – things like solo boosts, graphic EQs, foot-controlled volume, and remote channel switching. The TAE augments your amp with all of these capabilities.

Pedal tap dancing
One of the TAE's handiest features is the ability to save the configuration and settings for almost all of its functions and then instantly recall them via footswitch or the front panel. This allows you to reconfigure your entire rig with a single press of a footswitch. It also gives gives you something very akin to channel switching capabilities on your single-channel amp. You can, for example, dial up the perfect crunch rhythm sound on your amp, then for leads hit a footswitch that enables the TAE's compressor and delay, and activates different EQ settings. Oh, and it has a somewhat robust MIDI implementation, so it will work in coordination with any MIDI gear you already have in your rig. One nice touch: it will map MIDI program changes and automatically send out continuous controllers for up to 4 other MIDI devices in response to incoming program changes. Unfortunately, it doesn’t provide MIDI CC control over any effects parameters except on/off. (Well, I guess I should say that if it does, it’s not documented. That editor app is manipulating effects parameters somehow...) That’s a pity because if it did, you could use a MIDI control surface to configure the effects instead of having to always fire up the editor app.

Wallet Drainer

Now, you could argue that almost every feature that the TAE has exists in multiple other products on the market. And you'd be right. But as of this writing, only the TAE puts it all in one device. Like the iPhone, it replaces a lot of stuff.

At $1300, the Tube Amp Expander is definitely not cheap. But when you add up the cost of all the individual products you'd have to buy to get everything the TAE does, it's actually a pretty reasonable. Then consider how much easier it is to deal with a single well-integrated device (that happens to be built like a tank) and the price starts to seem very fair indeed.

Let me give you a pretty neat, illustrative example: A big part of Eddie Van Halen's famous "brown sound" was the result of running a Marshall plexi into a dummy load to bring it down to line level, then through his effects pedals, and then amplified with a separate power amp to drive his Marshall cabs. (By the way, there's some debate about that signal chain order but I'm going with my understanding and what my ears are telling me was going on...) That dummy load let him crank up his Marshall and control the volume. Running his phaser and flanger pedals post-Marshall made them sound a lot different from running them into the front end. If you think about it, the TAE provides all the core elements you need to recreate that approach – dummy load (in this case, it's a reactive dummy load which is better than what Eddie had), post-amp effects loop, and power amp – all in one box. Just add the Marshall and Phase 90 and we ain't talkin' 'bout love!

I'm telling you, convergence rules.