It's a bone simple, elegant transistor circuit that shares common ancestry with some other pedals you might be familiar with (along the lines of the Lovepedal Les Lius, Greer Ghetto Stomp, or Emerson Em-Drive) but with Caroline's particular twist on things, select batches of mojo unobtanium and pixie dust, and abundant heat from the NOS BC108 transistor pushing things. "The Blues" is simple and easy to use, and it includes a toggle switch which changes the pedal's gain structure.
More info from Caroline Guitar:
"If you thought three knobs and the truth was easy, imagine two knobs and a switch! The BLUES DOCTOR controls how much grit is in your signal. The BLUES LAWYER asks how you like your “blues”: vintage, or modern vintage? And the BLUES FINANCIAL PLANNER assesses the marketplace and decides how much 'blues' the audience can handle!
"On the inside there is a small trimpot marked CRYSTAL LETTUCE that sets the collector voltage of the BC108 transistor. This fine tunes the minimum gain and maximum range of the device. We set it to a healthy balance of 7 volts, but you may flavor it to taste.
"Yes, we all know the best amplifiers for this style of music should cost more than the average working person’s automobile, but if you aren’t #blessed to own one of those, 'The Blues' will deliver all the delicious artisanal mojo infusion vintage boutique hardwired bespoke sonic unobtanium you’ve ever been craving. On one mode the grit goes from minty well preserved black tolex to the warped particle board of a coveted pawnshop prize. On the other resides the crunchy, chewy sounds of that fraying tweed amp covered in drink glass stains and cigarette burns that the studio would never let you borrow cause they would never get it back.
"So even if you have led a life of relative splendor and comfort, what can you do when you’re having a ‘just my luck’ kind of day? You probably shouldn’t try to sing the blues, but you can certainly play 'The Blues.'"