In 2004 Boss released the GS-10, a tabletop effects system with built-in speakers and a USB audio interface. The GS-10 is one of my favorite Boss products and I always thought that if it had built-in rhythm patterns and loops, it would be a killer “desert island” practice device.

Although the Boss JS-8 ($399 Street) is part of the company’s JamStation product line and more of a sequel to the JS-5 rather than a descendant of the GS-10, it’s the machine that I wanted the GS-10 to be, and much, much more.

Boss describes the JS-8 simply as an audio player with guitar effects, but that description only scratches the surface of what it can do: It’s not just an iPod clone that you can plug a guitar into, as the company’s description might imply.

The front panel of the JS-8 is laid out intuitively, and I was up and running as soon as I took the JS-8 out of the box, without as much as a glance at the manual. Underneath a big blue display are buttons for Power and Song List, as well as playback controls (Stop, Play, Record, Rewind, Forward, A/B, Speed) and guitar controls (Tuner, Solo, and Effects). There is also a scrolling knob with five buttons surrounding it (Menu, left and right arrows, Exit, and Enter). On the bottom of the front panel is the guitar/mic input, the headphone output, and the Guitar Level and Master Level controls.

The back of the JS-8 has an SD card slot (it comes with a 1GB card but supports cards up to 32GB), a USB memory port, a USB input, an expression pedal jack, and a security slot for connecting a Kensington anti-theft security cable (see Fig. 1). The side of the JS-8 has Aux In and Line Out jacks.

Fig. 1: The RCA ins and outs are on the side, while the USB port is on the back.

Practice Makes Perfect
The JS-8 is solidly built and well balanced on its base. I expected it to topple over or move back when I—without supporting the unit—plugged my cable into the front panel input, but it held firm. The built-in speakers are not especially loud, but they have enough volume for bedroom practice. Optionally you can go from the line outs into a stereo or an amp. You can also play the JS-8’s audio files directly through your computer and its sound system when the JS-8 is connected via USB.

The JS-8 is loaded with 300 preset loops in a wide variety of styles. With an optional 32GB SD card, it can store up to 4,000 WAV and MP3 songs. You can group songs into a “Best 30” category to narrow your favorites and make scrolling through songs more manageable.

The preset loops are labeled by style, instrumentation, and key. However, the key that is listed is sometimes more of a general reference rather than a literal description. For example, one song’s progression although labeled as being in the key of D, had a progression that was derived from D Aeolian. The best approach is to use the indicated key as a guide for at least getting the tonal center and then let your ears or knowledge of theory dictate the appropriate scale choices.

You also get four free song downloads from guitarinstructor.com with the JS-8. I downloaded backing tracks to “Purple Haze” and “Sunshine of Your Love” for use with my students and it made the lessons more productive and fun for everyone.

The JS-8 has a metronome that goes from 40 to 250 bpm, with tap-tempo capabilities and a variety of time signatures. If the metronome is not to your liking, there are also preset drum patterns in most of the popular styles.

Model Behavior
The effects in the JS-8 are based on those in the Boss GT-10, the company’s current flagship multi-effects processor that offers COSM modeling technology. You can use up to seven effects simultaneously including Amp (modeled amps include a Fender Deluxe Reverb, a Matchless DC-30, a Mesa Dual Rectifier, and so on), FX (compressor, distortion, wah, etc.), NS (noise suppressor), Delay, Chorus, and Reverb. All of the effects can be edited and saved using controls found in the sub-menus.

Overall, the JS-8’s sounds are quite good, and the amp models certainly come close to the amplifiers they are emulating. From there you can tweak the settings to work with your particular equipment. While there’s no way a modeled Dual Rectifier coming out of the JS-8’s small speakers is ever going to “feel” like a Mesa stack, the Dual Rectifier’s tonal characteristics (liquid leads and long sustain, among other things) are definitely present in the amp model.

For The Record
The JS-8 has phrase-looping capabilities with up to 40 seconds of recording time. The optional Boss FS-6 twin footpedal gives you foot control over stop and record/play functions. I was able to get more than 40 seconds of recording time by bypassing the loop function and just using the JS-8 as a makeshift multi-track recorder. Using one of the preset rhythm patterns, I recorded a bass line and then overdubbed rhythm and solo parts on top of that track. Although the JS-8 is not specifically intended to be used as a multi-track recorder, it can be function as a quick sketchpad.

If you’re more serious about recording, the JS-8 has a built-in USB interface for recording into a computer DAW.

Training Day
The phrase trainer is one of my favorite features of the JS-8. It allows you to lower the speed of a selection by 50 percent or raise it by 150 percent. Although there are many other devices that also do this, the JS-8’s speed manipulation used in conjunction with its recording capability takes things to a different level.

I used the phrase trainer to slow down some fiery licks and after I got the notes, I recorded myself into the JS-8 playing my transcription against the original track. I was immediately able to hear whether or not my notes matched.

Even if you’re not big on transcribing, the phrase trainer is useful for working fast licks up to speed. You can play along with a lick at half speed and work your way up in increments until you get it up to full speed. The A/B button lets you set start (A) and end (B) points so you don’t have to constantly press stop and rewind if you’re trying to hone in on a specific fragment.

The phrase trainer also features a center cancel function, which removes the vocals of a song. When I used it, I still heard faint remnants of the voice, but nevertheless it helped me hear the guitar parts more clearly.

Another useful function is key change, which transposes the key of a song. At first, I was skeptical that it would actually work, so to test it, I recorded myself playing an open A-string drone and changed the keys during playback, comparing it against my guitar’s notes. Sure enough it worked as described. Moving the Shift sub-menu knob to +1 put me a half-step higher, into Bb. I transposed to a few other keys as well and they all checked out. This function was useful when I worked on songs that were recorded a half-step lower than standard tuning when I didn’t feel like detuning my guitar.

Convenience Is King
When I described the JS-8 to a colleague, his response was, “that’s cool, but I can do all of that using my computer and pedalboard.” And he was right; the JS-8 doesn’t break any new ground in what it actually does. However, the difference—and to me, this is really big—is the ease and convenience that the JS-8 provides.

There were days when I barely had time to practice. With the JS-8 I was able to sneak in five minutes of practicing at 2:00 AM, quietly playing and recording against the backing tracks, then listening to and critiquing the playback. If I had to turn on my computer, monitors, amp, and pedalboard, then find all the cables, plug everything in, and then try to work at a volume that wouldn’t wake the neighbors just to get in a few minutes of practice, it wouldn’t happen. It would take me about five minutes just to get up and running.

And remarkably, in a few short JS-8 practice sessions, I made a noticeable improvement in my playing; because everything I needed was immediately accessible, my energy was spent on quality practice time. That speaks volumes towards the design and feature implementation of the JS-8.

Pros: Great sounds. Convenient and easy to use.
Cons: None

NYC-based guitarist Joe Charupakorn writes for Guitar Edge magazine and is a best-selling author and editor for Hal Leonard Corporation. Visit him on the web at joecharupakorn.com