reverse engineered WH10 (dual pot version) SCHEMATIC ADDED!

[birt]

i'll have the schematic online very soon. i figured since i have to fix one i can just as well make it somewhat easier for me and others by having a schematic.

i also have a question regarding the single pot version that is already known here (and built by some?). (this one: http://www.freeinfosociety.com/electronics/schematics/audio/pictures/ibanezwh10.jpg )
to make it an allways on circuit (for true bypass) do i just have to get rid of the fet and hardwire where the source and drain was? so i can just leave the whole part that is connected to the gate out?

[birt]

here it is. the drawing isn't that good but i think it's clear. i'll add the component values (i just used the component numbers indicated on the pcb) later today.

now some questions... how can i make this an "allways on" effect? the bypass switch was only connected to the places indicated in the schem but near Q6 you can see a "?". thats a solderpoint right next to the bypass switch connections on the pcb and i don't really know what its for...

[free electron]

Remove Q3,Q2 and R14. Connect the C11 to R15 and Q4 gate. Simply connect the Q2's Source and Drain pads on the pcb. Then you'll have the "always on" and two spare FETs
Thanks for sharing the schem!

[birt]

R1= 470
R2= 510K
R3= 10K
R4= 2K2
R5= 3K9
R6= 22K
R7= 15K
R8= 6K8
R9= 4K7
R10= 100K
R11= 430K
R12= 10K
R13= 510K
R14= 510K
R15= 510K
R16= 1M
R17= 1M
R18= 22K
R19= 22K
R20= 10K
R21= 100K
R22= 470
R23= 100K
R24= 470
R25= 10K
R26= 10K
R27= 1K
R28= 1M
C1= .01
C2= 10
C3= 2.2
C4= .012
C5= .012
C6= .012
C7= .012
C8= 10
C9= 1
C10= 47pF
C11= .1
C12= .0047
C13= .1
C14= .0047
C15= 10
C16= 10
C17= 220
C18= 47
Q1= K30A
Q2= K30A
Q3= K30A
Q4= K30A
Q5= C1815
Q6= C1815
D1= 1N4148 ?
D2= 1N4148 ?
D3= 4.7V ZENER
D4= POLARITY PROTECTION
IC1= LM358N
DEPTH= 50K A
WAH A & WAH B= this is a 50K + 500K A dual pot but i don't know what side is what because my multimeter just crapped out.

[birt]

Remove Q3,Q2 and R14. Connect the C11 to R15 and Q4 gate. Simply connect the Q2's Source and Drain pads on the pcb. Then you'll have the "always on" and two spare FETs
Thanks for sharing the schem!

i guess i also have to connect the source and drain pads of the removed Q3 like i should on Q2?

oh and i'm really happy right now that what you just said is allmost exact what i figured out myself before i asked which means i'm learning


when i desoldered the switch i must have also desoldered something from the collector of Q6 right? isn't that the switching transistor that makes the status led go light up?

[Peter Snowberg]

i guess i also have to connect the source and drain pads of the removed Q3 like i should on Q2?
....
when i desoldered the switch i must have also desoldered something from the collector of Q6 right? isn't that the switching transistor that makes the status led go light up?

Leave the pads for Q3 empty. That transistor is there to pass the dry signal when the effect is off.

Q6 is an inverter which causes Q2's gate to see an inverted version of the bypass signal that Q3's gate sees directly from the switch. The LED is actually switched directly by the switch. I don't know what would have been connected at Q6's collector, but the value of the limiting resistor on the base (R28) is quite a bit higher than I would have expected.

Here is all the bypass stuff in red. Just remove all those parts and add the blue jumper. 

[birt]

great!
if someone feels the need to draw a nice looking schem for a DIY trua bypass version (and maybe some mods..) of this good sounding wah. feel free to do so!

does anyone have the other version? i wonder how they compare soundwise.

[Peter Snowberg]

One addition...

Since Q4 is just a follower, you could also remove R15, R20, Q4, and C11.  Now jumper from the + side of C15 to the junction of C10-C11-R11. I don't see any problem with leaving out the final buffer. Here's the updated pic.

[birt]

i just removed everything red from the first pic you posted. works great ^^

i'll try the update and then i'll have to find a replacement for the wah pot.
oh and i left in R27, D3, D5 and connected R27 to ground so the led lights up when there is power.

[Dirk_Hendrik]

Great job Birt! When comparing that to your reverse engineering stuff of say a year ago you're definitely learning fast!

[Dirk_Hendrik]

Old thread up.....

I ran into trouble yesterday while getting a WH10 to mod which was the dual pot version. I'm thankfull for Birt's post as it gave me a point to start but I did run into some errors while I was trying to get a picture of how this circuit should work.

Therefore a fresh redraw with some fixes:
http://www.dirk-hendrik.com/wh10dualpot.pdf

Use, redistribute but don't abuse.