My experience with this pedal is actually a bit different than many of the reviews here; I have primarily used the SD-1 as a distortion pedal with my solid state amp (mid-80's 35W Sidekick Switcher) and a Telecaster with Fender Noiseless pups. I'm not really a fan of distortion that takes away musicality, so this pedal has always been perfect for me- tons of musical sounding crunch with the 'drive' knob at 3:00 and the tone set at 11:00. And that's the way I've always played it, running it behind an MXR micro-amp clean boost and it sounds great! But recently I upgraded to a tube amp (Vox AC10 clone) and even though I know that this is MEANT to overdrive a lower volume tube amp, I just don't like the sound. It's too (and I know you're starting to roll your eyes) 'digital' or 'metal' through my Vox (no offense, metal bro's). The only way I like it with tubes is to drop the 'drive' really low and dime the 'level', but at that point I'm not getting much more crunch than if I just turned the amp up- which doesn't solve the ever-annoying "this club is tiny, how am I going to rock out with my amp at 3?" dilemma. Now, tone is totally subjective, and all amps/guitars/etc. sound a bit different, so it could just be my gear, but I have to say that while I love this for a tube-like drive for a solid state amp, it sounds cheesy with actual tubes.

In all other respects, though, this is a great pedal- built like a nuclear sub, with solid components and, though it's not true bypass, quiet circuitry. Classic Boss looks and easy battery change, if you like batteries (me, I'm a One-Spot fan, which works great for this pedal.) I know people who have had these things for years, gigging them night after night and they are still as good as new. Our lead singer even spilled a beer all over mine and it still works fine!

One functional complaint: mine ALWAYS comes on when I plug in my One Spot that powers my whole board (regardless of whether it was on or off the last time my board was plugged in), which is strange and sort of annoying since, depending on what's going on, that can mean a lot of feedback really fast. None of my other pedals do this... Not a big deal, but worth mentioning.

So, overall, a good pedal, definitely 4 out of 5 stars for me... I just prefer it through a solid state- if you're going for tube OD, maybe look into one of the endless "green driver" type pedals.
My experience with this pedal is actually a bit different than many of the reviews here; I have primarily used the SD-1 as a distortion pedal with my solid state amp (mid-80's 35W Sidekick Switcher) and a Telecaster with Fender Noiseless pups. I'm not really a fan of distortion that takes away musicality, so this pedal has always been perfect for me- tons of musical sounding crunch with the 'drive' knob at 3:00 and the tone set at 11:00. And that's the way I've always played it, running it behind an MXR micro-amp clean boost and it sounds great! But recently I upgraded to a tube amp (Vox AC10 clone) and even though I know that this is MEANT to overdrive a lower volume tube amp, I just don't like the sound. It's too (and I know you're starting to roll your eyes) 'digital' or 'metal' through my Vox (no offense, metal bro's). The only way I like it with tubes is to drop the 'drive' really low and dime the 'level', but at that point I'm not getting much more crunch than if I just turned the amp up- which doesn't solve the ever-annoying "this club is tiny, how am I going to rock out with my amp at 3? " dilemma. Now, tone is totally subjective, and all amps/guitars/etc. sound a bit different, so it could just be my gear, but I have to say that while I love this for a tube-like drive for a solid state amp, it sounds cheesy with actual tubes. In all other respects, though, this is a great pedal- built like a nuclear sub, with solid components and, though it's not true bypass, quiet circuitry. Classic Boss looks and easy battery change, if you like batteries (me, I'm a One-Spot fan, which works great for this pedal. ) I know people who have had these things for years, gigging them night after night and they are still as good as new. Our lead singer even spilled a beer all over mine and it still works fine! One functional complaint: mine ALWAYS comes on when I plug in my One Spot that powers my whole board (regardless of whether it was on or off the last time my board was plugged in), which is strange and sort of annoying since, depending on what's going on, that can mean a lot of feedback really fast. None of my other pedals do this... Not a big deal, but worth mentioning. So, overall, a good pedal, definitely 4 out of 5 stars for me... I just prefer it through a solid state- if you're going for tube OD, maybe look into one of the endless "green driver" type pedals.