JHS Bonsai / EXAR OD-1

[Fizz]

I would love to build one of these with a PedalPCB board someday. I'm especially interested in the EXAR OD-1 in it.. that one sounds the best of all the demos of the different pedals in it.

 

[ICTRock]

PedalPCB Little Green Scream Machine Exar OD-1 values
Resistors:
R3 453K
R6 33K
R11 jumper
R12 1M
R14 459R
R15 100K

Capacitors:
C1 47n
C3 100p
C8 47n
C9 1u
C11 100u
C12 omit

Semiconductors:
Q1 BC413
Q2 BC413
U1 AN4558

Pots:
Drive A1M
Tone B22K
Volume B47K

Exar OD-1 Schematic from FSB

There are some niggling differences but you'd be forgiven for building a tube screamer with R6, C1, C3, and drive pot changes only. That's the big difference makers. R6 sets a lower minimum gain, C1 increases the lower range of frequencies let into the circuit, C3 compensates for the larger drive pot that obviously increases maximum gain.

 

[Fizz]

PedalPCB Little Green Scream Machine Exar OD-1 values
Resistors:
R3 453K
R6 33K
R11 jumper
R12 1M
R14 459R
R15 100K

Capacitors:
C1 47n
C3 100p
C8 47n
C9 1u
C11 100u
C12 omit

Semiconductors:
Q1 BC413
Q2 BC413
U1 AN4558

Pots:
Drive A1M
Tone B22K
Volume B47K

Exar OD-1 Schematic from FSB

There are some niggling differences but you'd be forgiven for building a tube screamer with R6, C1, C3, and drive pot changes only. That's the big difference makers. R6 sets a lower minimum gain, C1 increases the lower range of frequencies let into the circuit, C3 compensates for the larger drive pot that obviously increases maximum gain.

Thanks! So grab the Little Green Scream Machine and sub in these parts? Can I use the NJM4558D from Tayda? I can't seem to find those transistors.. any good subs?

 

[ICTRock]

Without regard for transistor pinout, regular transistors like 2n5088 or mpsa18 would be fine. A regular 4558 is fine as well. I was pretty serious in that the suggestions I made are the difference makers. It's more or less a tube screamer so there's no need to be super accurate. JHS certainly isn't swapping all those differences out when you switch modes.

 

[Fizz]

Without regard for transistor pinout, regular transistors like 2n5088 or mpsa18 would be fine. A regular 4558 is fine as well. I was pretty serious in that the suggestions I made are the difference makers. It's more or less a tube screamer so there's no need to be super accurate. JHS certainly isn't swapping all those differences out when you switch modes.

That's good to know as I am a newb. I'll play around with this on a breadboard first and concentrate on those four component changes as I do it.