The BOSS WP-20G Wave Processor GK Effect

by Richard W. Webb

What it is

Q: OK, so what’s a GK Effect? A: One of the new line of guitar effects pedals by BOSS for the Roland-Ready, or, as BOSS calls it, the GK-Ready, guitar. Up front, that’s the down side of owning this pedal: if your guitar doesn’t have a GK style pickup, with its associated 13-pin DIN connector, nary a wave is going to get processed. But if you’re GK-Ready, then Get Set and Go to a new experience in guitar effects.

The WP-20G changes the guitar waveform into one of six different wave types, which I’ll cover in detail shortly. The important thing to realize now is that this box is not a synthesizer, and there is no MIDI involved, so don’t worry about its responsiveness – it’s there when you need it.

First things first

There’s one thing you’ll want to do right off the bat. Run around to the back of the unit (I’m kidding — it’s not that big) and flip that little slide switch labeled NORMAL PU MIX to the ON position. This lets you use the GUITAR / MIX / SYNTH switch on your GK pickup Controller to select between straight guitar, the wave processed GK signal, or a mix of the two. Also from the GK Controller, use S1 instead of pressing the WP-20G MASTER foot switch to turn the wave processed GK signal on or off, and use S2 instead of pressing the WP-20G EFFECTS foot switch to turn the wave processed effects (see below) on or off. Now you can set the WP-20G up off the floor to get the controls within easy reach. The GK Controller SYNTH VOL knob sets the level of the wave processed GK signal.

Basic operation is, well, basic. You switch in the wave you want to use with the TYPE knob, twirl the COLOR knob to modify the tone, and set the volume with the LEVEL knob. Then you can use the MODE switch to select from 5 types of delay, with or without a chorus effect, or choose chorus alone, or no effect if you prefer. The EFFECT LEVEL control is a little strange: the knob adjusts the amount of chorus effect when you are using chorus alone, or the level of the delay when using delay alone, but when you use delay and chorus combined the knob affects the delay level without affecting the amount of chorus. Well, with just one knob to do it all you have to make some design decisions, and this one does seem to make sense when you get used to it.

One more thing you need to know about the WP-20G: it has an effects send and return (two mono jacks) that let you run the straight guitar sound through external processing, such as a multi effects box or whatever you tend to use.

Making waves

Now let’s tour the TYPE selections. The first wave type, starting with the knob fully counterclockwise, is ACOUSTIC. Now I bet if you have a really nice acoustic guitar of your own, you may not use this setting much, but I personally have one of the worst acoustic guitars in the world (yes, Lord, I’m grateful that I have one at all; sorry), so if I want an acoustic guitar sound, I’ll use this one. It sounds pretty good to me. Turning the COLOR knob clockwise through its range changes from a warm resonance to a brighter ringy sound. My first impression was that it worked pretty much like a guitar’s tone control, just changing from a bassy sound to a trebly sound, but as I started to listen more closely I realized there’s more to it than that. The effect is partially that of a normal tone control, but there’s a bite to the note attack that remains throughout the range of the control. Nice.

Shankar very much

If I was designing a pedal like this, I’m not sure that I would have picked SITAR, since the pedal is being billed as a box that provides vintage guitar-synth sounds, but the wave kind of grows on you. I actually saw Ravi Shankar in a live performance in my younger years, and I’ve always been fond of the sitar sound, not only as used in rock, but also in a more traditional context. On this wave you get closest to the traditional droning sound with COLOR up past halfway, and with a touch of chorus added. With the COLOR cut back the wave loses the fullness of its drone, but it still maintains a twang with a touch of drone that would work in, say, a rock-a-billy kind of a song.

The next wave is called SLOW GEAR, and it’s basically, to my ear, the sound of Link Wray’s guitar on the classic "Rumble" but with the added twist of a variable attack time. Attack time increases as you turn up the COLOR. Love those backwards souding parts? This is one way to get that sound. Interestingly, the attack is not applied to the delayed sound, so choosing a quick delay with several reps gives you an unusual pre-echo kind of effect.

The Gong Show

The next wave brings back fond memories of when I was the sound guy for a local band and I put together a ring modulator for the keyboard player to use on his B-3. If you aren’t familiar with ring modulation, suffice it to say that it takes your oh-so-precise C major scale and turns it into a series of gong strikes in no key whatsoever. But hey, all music doesn’t have to adhere to the rigid rules of tonality as defined by the bearer of the Western ear. So the RING MOD type can be a lot of fun. This wave is one you’ll want to use sparingly (unless you’re alone in the house). As you twist the now famous COLOR knob up, the pitch of the internal oscillator increases. It seems to cover somewhere around a 2-1/2 to 3 octave range. If you use this wave at full tilt, adding in delay and / or chorus, you can get some really techno things going by playing ostinuto passages. Get a friend to slowly turn the COLOR knob for you and it gets really bizarre. And, by the way, if you add in just a little of this effect along with your straight guitar sound you can achieve a unique "spread" sound, sort of like a tube amp that has the bias set way off, producing a 60 Hz BLAAT.

Analog will do

The SQUARE wave type is just that, a square wave. Now we are really in the realm of analog synth speak. Even without chorus, this wave seems to have a wavering filter effect subtly insinuating itself. Square wave to the guitarist means distortion, and this does have an overdrivy kind of a sound, but the cool thing is this: you can have deep distortion and still play full six string chords. Turn the COLOR up and the sound gets brighter. Get someone to work the knob for you as you play and you can get some WAH happening.

The SAW LEAD sound is another analog synth standby. Like the square wave, the sawtooth wave (as the electrical cognescenti call it) sounds like a distortion type. In both cases the key to the sound is in the harmonics involved (but enough of the techie stuff). Play some parts in thirds or sixths with the COLOR twisted back and the SAW LEAD will make your guitar sound like a horn section. Yeah! And the COLOR is a brightness control again.

If only…

I’ve mentioned a few times that the COLOR knob is a thing you might want to twiddle while you are playing. What would make this box complete is a jack to plug in a remote pedal to do the COLOR. Maybe when my warranty runs out I’ll do that on mine. Maybe even before it runs out.

We have the power

Don’t try to run this thing on batteries. Buy the wall wart. I already had a charger so I ran right out and bought 12 AA rechargeable alkalines so I’d have two sets to alternately charge and use. I ended up having to put batteries in the charger twice a week, after only playing a few hours a week. So I bought the PSA-120T. Now all the TV and stereo controllers around the house are set for batteries for life.

And the verdict is…

All in all, I LIKE this box. It gives me a variety of sounds for my tool box that I don’t think I’d easily find anywhere else at a comparable price. Is it perfect? Complete? No! Would I buy one? I did!