Boss - SD-1w Super OverDrive (Waza Craft)
- guiddruid
- Breadboard Brother
Gut shots - https://imgur.com/a/UPaObOE
Not the best photos, sorry - cables get in the way. Really needs all the wires to be de-soldered to get a proper look at it.
Input is top-right of the circuit (W1 & W2), then heads down the right-hand-side, across & back up the left-hand-side. Looks like there ground plane on the component side of the board is split to improve input/output separation.
Most of the caps are through-hole.
A lot of SOT-23 transistor pairs "C6" and "DG". There are a couple of 8 pin ICs in there too. "99M"?
Lots of un-populated components.
Not the best photos, sorry - cables get in the way. Really needs all the wires to be de-soldered to get a proper look at it.
Input is top-right of the circuit (W1 & W2), then heads down the right-hand-side, across & back up the left-hand-side. Looks like there ground plane on the component side of the board is split to improve input/output separation.
Most of the caps are through-hole.
A lot of SOT-23 transistor pairs "C6" and "DG". There are a couple of 8 pin ICs in there too. "99M"?
Lots of un-populated components.
- roseblood11
- Tube Twister
Not worth tracing it. It's just a stupid SD-1...
These waza craft pedals are quite expensive, although production must be much cheaper than it was in the 80s. And they still use these unbelievably cheap caps and crappy ribbon cables.
These waza craft pedals are quite expensive, although production must be much cheaper than it was in the 80s. And they still use these unbelievably cheap caps and crappy ribbon cables.
- guiddruid
- Breadboard Brother
There are indeed no opamps in the circuit, unlike the original SD1 - the 8 pin ICs are switches (see below).
Opamps look to have been replaced with discrete transistor circuits. The drive and tone stages are not identical.
Input + drive stage is Q2(XG), Q18(DG), Q3(DG), Q4(JY), Q5(XG), Q6(XG)
Q4(JY) is controlled by the switching circuit, probably to mute & reduce bypass noise.
Passives & clipping diodes look very slose to original SD1 - clipping diodes D4,D5,D6 have same idents as in original SD1 schematics. IC2 is doing some switching here...
IC2 sw 2 controlled by S/C toggle switch. Doing something with the inverting input of the drive gain stage
IC2 sw 1 controlled by S/C toggle switch. Is creating an inverted copy of the toggle switch control (connects to IC3)
Tone stage is Q8(DG)/Q7(C6), Q9(XG), Q10(XG)
This is followed by Q12(DG)/Q11(C6), then Q20(XG),Q21(XG),Q23(DG)/Q22(C6). IC3 seems to be a bypass path around theese last 4 transistors.
IC3 sw 1 controlled by toggle switch. Connected to the final gain stage (Q20,Q21,Q22,Q23)
IC3 sw 2 controlled by inverted toggle switch. Connnected to the previous gain stage (Q11 + Q12)
So IC3 looks like it is switching in a whole additional gain stage
Main switching control circuit looks to be identical to original SD1 (and all other Boss pedals), which should help with identifying some of the other components. (Seems a bit weird to use a mix of discrete analog switching components and the 8 pin bilateral switch ICs)
Should mean DG = SOT23 NPN transistor
Also JY = SOT23 N channel JFET in switching circuit, not sure which way round drain & source are
IC2 & IC3 are Toshiba TC7W66FK, dual bilateral Switches
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XG = SOT23 something
C6 = SOT23 something, possibly PNP?
C1 = smaller than SOT23. Switching diodes of some kind. Clipping circuit & on FET gates.
C3 = some other diode. Used with the DG/C6 pairs.
D13 = C2 = diode at power supply connection
Opamps look to have been replaced with discrete transistor circuits. The drive and tone stages are not identical.
Input + drive stage is Q2(XG), Q18(DG), Q3(DG), Q4(JY), Q5(XG), Q6(XG)
Q4(JY) is controlled by the switching circuit, probably to mute & reduce bypass noise.
Passives & clipping diodes look very slose to original SD1 - clipping diodes D4,D5,D6 have same idents as in original SD1 schematics. IC2 is doing some switching here...
IC2 sw 2 controlled by S/C toggle switch. Doing something with the inverting input of the drive gain stage
IC2 sw 1 controlled by S/C toggle switch. Is creating an inverted copy of the toggle switch control (connects to IC3)
Tone stage is Q8(DG)/Q7(C6), Q9(XG), Q10(XG)
This is followed by Q12(DG)/Q11(C6), then Q20(XG),Q21(XG),Q23(DG)/Q22(C6). IC3 seems to be a bypass path around theese last 4 transistors.
IC3 sw 1 controlled by toggle switch. Connected to the final gain stage (Q20,Q21,Q22,Q23)
IC3 sw 2 controlled by inverted toggle switch. Connnected to the previous gain stage (Q11 + Q12)
So IC3 looks like it is switching in a whole additional gain stage
Main switching control circuit looks to be identical to original SD1 (and all other Boss pedals), which should help with identifying some of the other components. (Seems a bit weird to use a mix of discrete analog switching components and the 8 pin bilateral switch ICs)
Should mean DG = SOT23 NPN transistor
Code: Select all
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io1 1 8 vcc
oi1 2 8 ct1
ct2 3 7 oi2
gnd 4 6 io2
XG = SOT23 something
C6 = SOT23 something, possibly PNP?
C1 = smaller than SOT23. Switching diodes of some kind. Clipping circuit & on FET gates.
C3 = some other diode. Used with the DG/C6 pairs.
D13 = C2 = diode at power supply connection
- guiddruid
- Breadboard Brother
Thanks dv8r601 - that doesn't make sense, given where they are in the circuit though. The NXP datasheet for BA199 also says the markings would be "JYp", "JYt" or "JYW", and that's not the case here.
- guiddruid
- Breadboard Brother
Found a good reference for SMD markings; http://caxapa.ru/thumbs/588912/smd-codes.pdf
Have some promising candidates for some of the mystery 3 pin devices.
JY, SOT23 N channel JFET in switching circuit
2SK208, IDSS classification 1.2 to 3.0 mA
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DG, NPN transistor of some kind, bistable for footswitch + gain stages
2SC2713
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C6, transistor of some kind (Q7, Q11)
MMBA811C6, PNP
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Nothing sensible for XG yet...
Have some promising candidates for some of the mystery 3 pin devices.
JY, SOT23 N channel JFET in switching circuit
2SK208, IDSS classification 1.2 to 3.0 mA
g
[-+-]
[+-+]
s d
DG, NPN transistor of some kind, bistable for footswitch + gain stages
2SC2713
c
[-+-]
[+-+]
b e
C6, transistor of some kind (Q7, Q11)
MMBA811C6, PNP
c
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[+-+]
b e
Nothing sensible for XG yet...
- nooneknows
- Resistor Ronker
the boss Instagram post reports that the tone circuit is differently tailored from the standard SD-1 in mode classic, it would be interesting to know the tone/resistor cap value.
- Lani
- Solder Soldier
The (XG) sot23 is a 2SK209-GR jfet. Here is a link to the ones I purchased. Not a bad price really... they are on sale now too!!
https://lcsc.com/product-detail/JFETs_T ... 61792.html
https://lcsc.com/product-detail/JFETs_T ... 61792.html
Information
I reported tracing SD-1W on X(Twitter). Here is the schematic.
Blog link (Japanese)
https://drugscore.blog.fc2.com/blog-entry-334.html
Blog link (Japanese)
https://drugscore.blog.fc2.com/blog-entry-334.html
- george giblet
- Resistor Ronker
Your schematic looks good. I traced this back in Aug 2019 and forgot all about it. I couldn't work out some of the values of the smaller compensation caps from the photos. Perhaps a few other parts were missing. I compared the two schematics and they agree.kanengomibako wrote: ↑14 Feb 2024, 14:56 I reported tracing SD-1W on X(Twitter). Here is the schematic.
Blog link (Japanese)
https://drugscore.blog.fc2.com/blog-entry-334.html
I remember when I looked at it back then the whole extra discrete opamp for the custom mode isn't doing much really. You could do the same thing with an RC network. I have a feeling Boss wanted to add a bit more gain to make it sound "more" than Standard mode (instead of or less, which is what would happen with a passive network).