I wanted to try the new Ashdown Labs stuff after reading about their design philosophy and noting that the input could match a piezo pickup. I take it that the Ashdown Labs range is their high-end stuff - the other Ashdown series are not. There are only 2 heads in the AL line, the 500 and the just shipping 600 - which seems very similar to the 500. I ran my Clarus SL (as a control), a new WW Super and an Ashdown Labs Mark King (AL-MK500) with my AES DB/Fishman Full Circle and LDS cabs (both the 2x8 and 1x8 3 ways). I ran the Full Circle straight in. I only did a few hours of comparisons (three separate times through the test) and I was playing solo, but I can tell you at least what I got so far. Both the WW and AL were much more accurate sounding than the Clarus SL which came across as overly warm and thick (but how can you fault a 40oz amp, now really!) What you notice right away is that the AL doesnt have that slight drop off on the 'E' string as the WW does. You also notice that it's VERY close to the WW sound, with the WW being a bit thicker (!) or warmer sounding, and the AL, dare I say, seemed more accurate (!!!), cleaner and dryer, without getting sterile. I almost got the sense that the WW is like an electric car trying, almost successfully, to run with a very evolved conventional engine. The WW felt a bit transistory at times like it was adding an er-er sound to the midrange. I wouldn't say the AL is better sounding yet, but I wouldn't be surprised that I'll feel that the more I use it. I guess I can conclude so far that it's more even throughout the whole range of the bass, just as accurate as the WW and it seems more powerful. A few other mentions...the ALs fans are quiet and residual noise is nil. I used the input level control at full or near full. It worked fine and there was no added noise. The build quality and controls are as good as anything Ive seen or used. I really enjoy the automatic muting for turn-on and turn-off no thumps or crackles out of the speaker...funny how this little detail makes one feel more secure about a product. Of course, the AL is not as portable as the WW. It weighs 20lbs, which is not a disaster, and is wider than the WW. It's also just a single channel. But offsetting this is the fact that its half the price of a WW and you can order actually buy it without months of waiting. Notes: Im very partial to accuracy reproducing only the sound of the DB without color. Thats my goal and if its not yours, then these results wont matter. I havent run this with a band yet, and these impressions are very preliminary...but the results were so unexpected that I figured Id stick my neck out and post it. I hope someone out there tries one of the Ashdown Labs heads and reports what they think.