Green Bean to MP Little Green Wonder

[Jcat5503]

Anyone know if it's possible to modify/change components to convert a Green Bean PCB into a LGW circuit? My Cosmo board that was converted to LM specs sounds KILLER. Just curious to see if it's possible

Cheers

[jkokura]

Potentially. Have you compared the schematics to analyze the differences?

Jacob

[jtn191]

There's a bunch of little changes--I had a quick look and the most complicated part would be incorporating the dual gang body pot

here's the schems (top one is easier to read)

[Jcat5503]

There's a bunch of little changes--I had a quick look and the most complicated part would be incorporating the dual gang body pot

here's the schems (top one is easier to read)

Thanks for posting this. You guys think it's worth doing? How hard would it be to incorporate the dual pot?

[jtn191]

Actually it's a bit more involved of a mod than I thought... There isn't an output buffer, the power filtering is different, and and the Tone pot is left out completely and the dual gang Body pot is wired up at another place...
I need to do homework now, but if anyone wants to pick up where I left off...
Here is a vero project for the LGW http://tagboardeffects.blogspot.com/2012/03/bjfe-little-green-wonder.html

Here's how:
Differences are in yellow
power filtering section is quite different, you might be able to try the "stock" one
The LGW doesn't have an output buffer so the components that are part of the buffer can be omitted
*C1 and R2 are swapped in the schematic, but this shouldn't make a difference
R1: 1M
R2: 5.6K
R3: 1M
R4: 10k
R5: 27k
R6: 2k
R7: 5.6k
R8: 2k
R9: 27K
R10: omit
R11: 2k
R12: 1k
R13: omit
R14: omit
R15: omit
R16: LGW schem omits this
R17: ...
R18: ...
R19: ...

C1: 47n
C2: 1uF
C3: 100pF
C4: 220nF
C5: 68n
C6: 220nF
C7: 220nF
C8: 1uF
C9: omit. The pad touching lug 2 of the volume pot becomes your new output
C10: omit
C11: ...
C12: ...

D1-D5: Green LED (or your choice for mod)
D6 ...


Q1: 2sk170 *check pinout
Q2: omit LGW. doesn't have an output buffer

IC1: TLC272CP

*same switches as in stock BOM

Drive: 500KB
"Body": 20k dual gang
Vol: 50k B


btw, the Clay Jones OD was pretty hyped and I did a similar write up here http://www.madbeanpedals.com/forum/index.php?topic=3817.0

[Rockhorst]

I've often wondered about the input/output buffers of the TS. Do they contribute to the sound? I think it would at most be a very small contribution. Originally it was also part of the switching system, but the
circuit can be adapted to have a high enough input impedance not to need the buffer (Eternity/SoS). The output of the second opamp is quite adequate at driving the rest of the chain. I see Screamer clones with and without the input/output buffer or just one of them and always wonder why...One of my upcoming projects is a Screamer Lab based on Green Bean...Might make the buffers switchable or leave them out all together...