[Colorsound Power Boost]
Here's the Colorsound description:
"So what's the difference between the Power Boost and the Overdriver ?? Um . . . .nothing ! Except the case . The Power Boost was born in the late sixties - the idea was to give guitarists a boost . . . . . in power , and it did ! Guess it was just luck that when you turned the pedal up full it sounded like the best stack ever ! We we're really popular with glaziers in those days , windows were shattering right accross London ! Then the pedal was taken to the Dallas trade show where it was given a huge standing ovation ( like clapping - the guitars hadn't been invented yet ) and a bunch of flowers - you see the American market was ready for the sound but felt it looked a bit too . . . well . . .orange .
So , it was rehoused in a grey hammerite case , called the Overdriver , Jeff beck made 'Blow by Blow' with it , and the rest , as they say , is a mystery . . I mean history ! Recently I was lucky enough to be presented with three , unused Power Boosts circa 1968 - they we're still in their packing , never been sold - they sounded just great - just like a new one ! No kidding - I A/b tested the pedals old and new and blindfolded I couldn't tell the difference . . . well I could have felt for the master volume - we have added that - windows are expensive these days !"
And a demo video of the Powerboost/Overdriver in action:
Here's some gut shots:
And the schematics of the different variations there have been over the years:
And here's a vero layout for the Overdriver:
Here's a great article covering all aspects of the Overdriver/Power Boost: http://www.kitrae.net/music/Music_mp3_Colorsound_Sound.html
And the forum topic on freestompboxes for extra tips and discussion: http://freestompboxes.org/viewtopic.php?f=19&t=1153