Hi All.. I'm building a bluesbreaker clone, and got some links from aron's site, but, looking at the drawings I had a little question.
The Gustav Smalley's schematics looks a little diferent from the tonepad's.
On Gustav Smalley's, on the first stage, the 0.01uF cap goes to the ground
http://www.diystompboxes.com/pedals/bb.gif
But on tonepad's it goes to 1/2 Vcc..
http://www.tonepad.com/getFile.asp?id=75
Wich one is right?
And, sorry for the dumb question.. :roll: On Gustav's one there is a wire after the first stage that seems to go to a switch and connects it to the input.. Is it a bypass for the first stage ?
Again, sorry if this question seems dumby... :oops:
Tks all in advance !
Heya. Those are pretty good questions. They're both right, it's just two different ways of accomplishing the same thing. The switch is for bypassing the pedal :)
Perhaps more accurate is to say both configurations will work. The actual units are only made one way. If I had to *guess* I'd say the connection went to ground - only because a few other marshall schems of that era use the ground connection.
Tks 4 the quick answers..
At first I thought the switch was to bypass the pedal , but it seems to connect the input directly on the second stage ( I'm talking about the wire between the two 4k7 resistors on Gustav's schem).. Is it right ?
Ah, those 4.7k's.
The switch shorts the signal between the 1st and second stage in bypass mode to prevent the distorted signal leaking through in bypass-mode. In effect-mode the two resistors look more or less like a single 10k. The resistor is split so the signal can be shorted without loading the first opamp and without introducing noise and oscillation problems at the second opamp.
The difference between the 10k and the 2x4.7k's is due to the different switching arrangement.