On Sunday, I traded my unused SD-1 for a Marhshall Guvernor Plus (II), in box, not new but in box... It's a pretty good overdrive and I think I made a good deal. I have to fix the bottom plate but it works perfectly... and sounds really good too... I am thinking of trading it later for a DS-2 or an MD-2, which are the pedals I really want now... no use for another overdrive in my pedalboard (I already own the OD-3)...
This is certainly an interesting sounding pedal. I'd say it's a cross between a phaser and an auto wah. With speed turned up full it sounds to me like a univibe-type sound, I will need to learn Pink Floyd's 'Any Colour You Like' (edited because I didn't know my Floyd..) The depth control is also a phase selector (At least according to some reviews I've read - it functions as a switch as well as a potentiometer) though I need to use it more to discern the sound differences.
The picture above is after I cleaned it up. The top was broken off one of the knobs but luckily the parts were all in the box - I also glued the broken ac-jack back together.
Like my other Guyatone pedal (the PS-109 Delay) the footswitch does not click - it is a silent switch. The LED stays on whether the effect is engaged or not, maybe a battery indicator rather than an effect indicator.