I was recently able to pick up a Kustom Groove Bass 1200 for a crazy good price off ebay (thanks for the heads up, Quadzilla!), and it is going to be passed on to another TBer (you know who you are! ). But, before I handed it off, I wanted to do a little comparing with some of my other solid state (or hybrid) heads - imagine that! The lineup looked like this: Walter Woods Ultra Mesa Boogie Walkabout Kustom Groove Bass 1200 Mesa Boogie Basis M-2000 Warwick Pro Tube IV EA iAMP 800 This is somewhat of a disparate bunch, but hey, it's what I had on hand! I wish that I still had my AMP BH420 (or a Thunderfunk) to throw in the mix. Here's the required visual: All testing was done with the Accugroove Whappo, Jr. (it was handy, and I am very familiar with this cab) and I played predominantly through my Skjold Custom 5 (my "go to" bass, and the instrument with which I am the most familiar). I also played a bit through my new (to me) Ritter Roya 5. My playing style is predominantly fingerstyle, and I hit the strings fairly hard. I took the picture before I played around with the amps, so don't pay attention to particular knob settings. Except where noted, I tried to set each head "flat" (maybe "normal" is a better term) for comparison purposes. I should also note that all of these heads offer sufficient tone control to enable a player to dial in a drastically different tone (or range of tones) from the "overall tone" I am describing for each amp, below. My observations were as follows: Walter Woods Ultra: This amp has fantastic headroom (1,200w into 4 ohms), and it shows. The high end is detailed and decidedly uncongested. The midrange is sweet, clear, and very articulate. The low end is full with a hint of warmth, but not sloppy - somewhat reminiscent of a good tube amp. It is hard not to gush about this amp. It sounds "beautiful", for lack of a better term. I for one do not think that the WWU is strictly a "flat" or "accurate" amp. Walter spent a lot of time dialing in the tonal characteristics of this amp, and he intended it to have a character of its own. But with that said, the tonal characteristics of the WWU never seem to get in the way of the tone of the related gear (basses, cabs, etc.), and almost universally come across as complimentary "flavoring." The fact that this little monster weighs in at just over 7 lbs is even more impressive. The only thing that I'm ever left wanting are the super tight/forceful lows that I get from the iAMP 800 - although by comparison to pretty much any other head, it has plenty of full, tight low end. Mesa Boogie Walkabout: This little amp has killer tone at low to moderate volumes. When you push it hard, though, the lows seem to loose focus before the mids/highs. Still, I believe this to be a very loud 300w into the Jr.'s 4 ohm load. It had more useable volume than the 400w Warwick and close to as much useable volume as the Groove Bass (though I really didn't push this issue). The Walkabout also allows for a very nice tube overdrive, if you crank the Gain and back off on the Master. On the whole, this head has a lot of midrange presence, and playing with the sometimes confusing Mid control is a must. Kustom Groove Bass 1200: This amp has a nicely warm (but not muddy) tone with the controls set "flat." The tone was nicely balanced, and it did a great job of balancing a full, warm tone with good clarity and articulation. In fact, I found the "flat" setting to be exceptionally nice sounding, but the Groove Bass does allow you a lot of EQ contol (though the "Sub" setting on the Bass control seemed to be voiced too deep to be very useful, IMHO). This was the least expensive head (going off new prices) in this comparison by a substantial margin, and it did show in some ways. The most obvious is that it was obviously more susceptible to either grounding issues or EMI/RFI issues. I didn't have a cheater plug on hand to test the grounding issue, but none of the other heads had a problem (and the Kustom wasn't bad, just a tad noisier than the others). Also, it was not as dynamic at lower volumes (but had good attack as you turned it up). On the whole, it just didn't feel as "crisp" as the rest. The Groove Bass could put out some substantial volume, but I didn't get the sense of limitless headroom like I get with the WWU, iAMP 800, and M-2000. Also, the Walkabout sounded closer in output than there ratings would seem to indicate. But it most definitely put out gig-worthy volume with the Jr. Mesa Boogie M-2000: This is probably the most potentially vexxing amp in the lineup, but in some ways, one of the most promising, too. There are two preamp sections (one "FET" preamp and one "Tube" preamp), with the ability to blend between the two. It definitely needs EQing, and it's probably the only one of the bunch that I definitely would not play with the tone controls set "flat." With some EQ-ing, though, it presents a very wide range of usable tones, from the very clean to the very overdriven (with options to footswitch between these options!). I really do like the overdriven tones coming from this amp. The tone in general is round and full, and the notes don't sustain like they do with some of the other amps. The FET side, in particular, seems to have a stronger upper midrange presence. While this amp is rated at 600w, it sounds louder to my ears, and it could push the Jr. as hard as it wanted to be pushed. Warwick Pro Tube IV: This is a very different head from the rest of the group. It is also two-channel setup, like the M-2000, but you cannot blend the two. In addition to the standard 12AX7 class preamp tubes, it also includes an EL-84 for "power amp" overdrive/distortion (though the amp section is all solid state). This head offers a huge variety of overdriven tones, and this seems to be its focus. It can get a very good clean tone (in truth, an exceptional clean tone, at that!), but I can't figure out how to maintain that clean tone to full volume output. Whenever I try to turn up the gain to get the volume that I want, I end up with some degree of overdrive. Maybe I need to spend more time with this amp. At any rate, it can get a very good clean tone at lower volumes, and it can also present a wide range of nice (and unique) overdriven tones. EA iAMP 800: Being very familiar with this head, it did not surprise me when it made the impression of not making an impression. The iAMP 800 is tonally very neutral, IME/IMHO, and as such, there isn't any one tonal characteristic that jumps out at you. But then you do notice how full, tight, and authoritative the low end sounds. This is the iAMP's forte, and I have not found another head (tube or solid state) that has the tight/full lows of the iAMP 800. The high end on the EA is not quite as bright or in your face as some other heads, though, and with Accugroove cabs, I generally like to tweak the highs up a bit on the iAMP. On the whole, the iAMP 800 is not as initially "exciting" sounding as some of the other amps (including the Thunderfunk TFB420 that I tried a while back), and its presentation is a bit more warm and smooth, but with very quick transients and excellent dynamics. So, at the end of the day, the Groove Bass was not my favorite head in this roundup, but I did feel that it acquitted itself very well in some pretty impressive company. For it's price, new, I am very impressed. Later, Tom.