I ordered one but was curious if anyone had any experience with it...
http://www.pennypedals.com/index.php?page=DS-1-Bass-Mod 
This was one person's review:
I am not sure if anyone will be interested in this, some of you will probably already have one, but I bought one last week and was so impressed that I felt I had to share my happiness with all of you.
What I am talking about is a Boss DS-1, modified for bass by Penny Pedals. Up till now I have been using a Fulltone Bassdrive, the comp-cut setting for a bit of boost and fattening and the normal or the vintage settings for a touch of overdrive. Basically I think the Bassdrive is a superb and versatile pedal that is pretty much always on. So I really wasn't looking for a new distortion/overdrive pedal, but when I stumbled across this one I was immediately attracted by the good old industrial Boss looks (I have always liked the idea of an orange Boss pedal in the same way that I am turned off by the yellow bass overdrive pedal). I was also attracted by the price, although the DS-1 is probably the cheapest Boss pedal, the mods by Keeley or Analogman are more expensive and not bass-centric.
Getting it over here
Dealing with Matt at Penny Pedals was very easy, and as he had one ready to go, it was very quick too. It also went through customs very quickly
Plugging in
The pedal basically works in two settings: Distortion (ie what the Boss pedal was originally intended for) and Overdrive, selected by a toggle switch added to the top of the unit (with the penny pedals penny). The pedal has also been modified to give better bass response and tonal control.
Plugging in and using the DS setting, the first thing I noticed is that the increased bass response is very noticeable, in fact it is quite immense, and this gives a fun distortion sound. As you would expect, it is not exactly a natural distorted sound, more artificial with a bit of bass tacked on- which is exactly what it is- like putting your generic distortion pedal through a blend control. This was definitely the sound I was expect and the sound I intended to use the pedal for. But then I flicked the switch...
Overdrive
The OD setting is frankly brilliant. This setting offers a warm, fat, creamy bass sound with a hint of crunch coming through, and when you crank-up the knobs this becomes a full-on growl with minimal loss of bass. Interestingly when the distortion knob is almost fully turned anti-clockwise and the level knob turned down, the pedal offers some useful clean boost.
I used this pedal with my band this week and I didn't turn it off for the whole session (and it was a long session). I mostly play with a Waterstone semi-hollow, which has a pretty formidable low end, but this pedal blew everyone away.
In conclusion
This is a very useable distortion pedal for bass, but more than that it is a great overdrive pedal and is deceptively versatile. Perhaps not as versatile as a Bassdrive, but the stuff it does well, it does better than the Fulltone and so may well replace it as my 'always on' pedal.
