Groove Tubes Spacestation SFX MkII

That keyboard sounded pretty killer through those compact stereo speakers on the music store wall. It sounded even better when you brought it home and ran it through your studio monitors. Then you brought it to band rehearsal, and something happened. That rich sound you fell in love with was gone, and you had a hunch it might have something to do with that lone audio cable going from your keyboard’s “L/mono” output into your either underpowered or heavy-as-sin amplifier. Sure, you’ve been tempted to “go stereo” and spring for the second amp (or portable powered PA speaker), but you already have enough gear to lug around.

Groove Tubes aims to solve your dilemma with the Spacestation MkII. Weighing in at only 32 pounds, the MkII delivers stereo amplification from a very portable single cabinet, using what Groove Tubes calls SFX technology: An extra speaker faces 90 degrees to the right from the front speakers, and the system splits the input between this and the mains, creating up to a 300-degree stereo spread. It doesn’t just send one channel to the front and the other to the side; instead, an encoding circuit looks at the whole picture and sends different information to the front and side speakers. If you’re a recording buff, you’ll want to know that it’s the same principle as mid-side miking, only in reverse. If you’re not, you’ll still want to know that the resulting stereo effect is pronounced, immersive, and very pleasant — but it’s a different sound than having your left and right keyboard outputs feed identical left and right speakers.

The models before the MkII came in two flavors: The Spacestation had stereo inputs, and the SFX-100 (reviewed July ’06) targeted the solo coffeehouse musician by adding reverb and an XLR mic input. Groove Tubes left these off the MkII because of customer feedback that most players just wanted a straight-up instrument amp. So you get left and right 1/4" audio inputs, master volume and width knobs, and a 1/4" line output for a powered subwoofer.

What’s interesting about that “sub out” is that it provides full-range audio, not just bass. You get a mono-summed, non-powered output that you can amplify as you wish. You might ask, “Why don’t they just call this a line out?” The answer is that when the sub out is in use, the MkII cuts bass below 100Hz to its own speakers. Combined with a subwoofer (or amp that handles low end well), the Spacestation becomes more efficient and delivers more power for frequencies above 100Hz. You get to have your cake and eat it, too — stereo sound from the Spacestation, and low-end punch or more loudness from whatever you plug that sub output into.

Don’t be deceived by the small footprint. This is one loud amp, noticeably louder than the original Spacestation and SFX-100, even when used all by itself. You can definitely hold your own in a band setting for personal monitoring, and the MkII can be your main source in all but very loud rock bands, provided your bandmates are professional about their stage volume. To my ears, its tone color makes it optimal for vintage keyboard sounds, especially electric pianos and organs. Turning up the width knob really brings rotary speaker emulations and stereo-panning Rhodes tremolo to life. I was a bit underwhelmed by how it reproduced straight acoustic piano sounds, though. Stereo digital pianos tend to suffer greatly when summed to mono, so the stereo projection definitely gives it an edge over many other keyboard/combo amps, but the tone lacks some of the clarity of today’s compact powered PA monitors — on the other hand, for stereo, you’d need two of those. Since the MkII projects sound in such a wide field, the stereo width knob is great for tailoring the output to the room you’re playing in. For “drier” rooms, a wide spread is the way to go. For more reflective rooms, roll back the width, and you’ll still get the stereo imaging, assisted by reflections from the room.

The Spacestation MkII is, in a word, practical. It’s got power to spare, it’s very portable, and it’s ready to fill a room with lush stereo sound. The stereo width knob gives you control over how lush and wide that gets, but otherwise, the MkII truly embodies the spirit of “plug and play.” If your sounds feature a lot of stereo effects, and you fancy the more vintage side of tone, the Spacestation MkII could very well be your low-profile gigging solution.

WHAT’S NEW IN THE MkII?

• The cabinet has been retuned for louder output and extended speaker life.
• There’s now a 2" port in the cabinet for extended bass response.
• Groove Tubes has added an additional heavy-duty passive crossover at 400Hz.
• It’s now the only model in the line, and unlike the original SFX-100, has neither a mic input nor onboard reverb.
  

Keyboard amp with side-facing speaker and stereo sound field processing.

Pros
Ultra-portable. Convincing stereo effect from a single cabinet. Lots of power and volume. Line output lets you augment Spacestation with subwoofers or other full-range amps.

Cons
No onboard EQ/tone controls. Tone color not optimal for acoustic piano sounds.

$599
Groove Tubes, www.groovetubes.com

VITAL STATS

RATED OUTPUT POWER 200W (100W to front speakers, 100W to side).

SPEAKERS Front: 8" woofer, 1" compression driver, super tweeter. Side: 6.5" full-range speaker.

AUDIO INPUTS 1/4" unbal. L and R.

AUDIO OUTPUTS 1/4" full-range mono sum.

DIMENSIONS/ WEIGHT 18" H x 11" W x 11" D; 32 lbs.