Orange Bass Butler  [schematic]

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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tuck
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Post by tuck »

Hey lovers of the deep tone,
attached you can find my attempt to trace this big tank.
It's my second attempt to trace a pedal so please be kind. I used a continuity tester and the magnifying glass app with the flashlight of my cell phone to get it done. The schematic is made with Kicad.
Unfortunately I don't have a lot of knowledge in electronics. I don't now exactly which component is part of a feedback loop and which is a high pass etc or (and) especially for this pedal which component is related to which module (if this is the correct term). I tried to figure it out the best I could.
I split it in six groups:
"Comp & Clean"
"Clean XLR Out"
"Dirty"
"Dirty XLR Out"
"Power / FS / LED"
"Output"
I bet the arrangement of the parts is not what you would usually see but as mentioned above....
At first I wanted to get it done by myself and verify it but it would take weeks and threads with a lot of questions.
So here it is. Feel free to bombard me with information which components should be displayed in a different arrangement and which component is connected in a way it shouldn't be connected.
If you need a different angle of a specific part of the pcb please yell at me. I will update the pictures in a few days as not every component reference is visible.
I wasn’t sure about the color code of two resistors so I wrote both possible values. Most of the time it was easy to decide which ring is the first one but not always…
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bassbutler.pdf
(197.7 KiB) Downloaded 344 times
front2.jpg
front1.jpg
back2.jpg
back1.jpg
Last edited by tuck on 07 Dec 2022, 23:38, edited 1 time in total.

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Manfred
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Post by Manfred »

Hi Tuck!
Great work! :thumbsup

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Post by blackboarcult »

Impressive! :applause:
The topology of the Drive section is pretty much the same as the Rockerverb...
I like that they haven't just swapped jfets for tubes and stuck to the original values, a lot of them are scaled to half-ish.
I hope somebody will trace the Orange Super Crush 100 soon, and I bet it won't differ much from this :)

I assume R19 is 1k? R33 is likely 8M for impedance reasons.

R34 and C16 form a low-pass at 7k, nice to get rid of jfet fizz, then C17 and R36 a high pass at 700hz-ish, quite possibly to tame any boominess left after the gain stages.

Thanks for your hard work! ;)

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Post by Lani »

Impressive man.... Good work indeed. :thumbsup

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Post by tuck »

Thank you guys!
blackboarcult wrote: 08 Dec 2022, 11:23I assume R19 is 1k?
brown black black brown brown = 1K or 110R
Almost all of the resistors have a brown ring for tolerance but brown on both sides makes it a bit hard if you don't have the background in electronics :-)

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Post by Manfred »

tuck wrote: 08 Dec 2022, 13:02 Thank you guys!
blackboarcult wrote: 08 Dec 2022, 11:23I assume R19 is 1k?
brown black black brown brown = 1K or 110R
Almost all of the resistors have a brown ring for tolerance but brown on both sides makes it a bit hard if you don't have the background in electronics :-)
1k

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tuck
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Post by tuck »

Ah now I see... I used a "1" as placeholder for components where I did not know the value yet... Sorry I missed it.

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Post by bajaman »

Well done Tuck - not too shabby for a newbie to tracing :-)
However, sorry, but there are quite a few mistakes - the input Jfet buffer is fine but the circuitry around IC2a and IC2b is a calamity - the treble control and bass control are vice versa and the feed off to the compressor section does not go through R57 - many more faults but do not worry - I am on to it :-) I have made a clone of the board layout using your excellent front and back pictures in Sprint Layout V6.0 - a great little PCB design program that allows importing of scaled bitmap images to make track tracing and component placing a breeze - I highly recommend this cheap and easy to use program and it is so EASY to use !
In the meantime (just in case someone rushes to build this according to your pdf) - please be patient and a corrected working version will soon be uploaded - unless someone beats me to it, but that's okay - once again, thanks for all your fine work on tracing this pedal - the jfet section alone would make a great overdrive ;-) Nice to see that the designer has decoupled each Jfet stage too ;-)
Take care
cheers
bajaman

ps: it would be nice to have the kicad schematic file to speed up the corrections ;-) Please upload it if possible
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tuck
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Post by tuck »

Here you go.
Can you please show me afterwards what I did wrong so I can recheck?
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bassbutler.7z
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Post by tuck »

The scratched trace on C39 (you can’t barely see the 9) is also visible on pictures on the net.
I habe a serial number in the 2** range. maybe there is a newer revision available.
Edit: wrote R39 buts its the red C lower left side….

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Post by bmxguitarsbmx »

bajaman wrote: 09 Dec 2022, 22:36 Well done Tuck - not too shabby for a newbie to tracing :-)
Yes I agree. fantastic job tracing. Very readable schematic as well.

Things that look strange to me:
1) Output section where CL and DR outputs mix. Seems weird to have two op-amps here, but then decided to mix the output with 1k resistors (R81&R82)

2) Jfet Drive section at the tonestack. I am going to go ahead and claim that the tonestack is connected on the other side of C17. C17 is NOT part of a highpass filter but is part of a Low-Shelf with R36. Additionally, RV5 is likely a standard setup master volume.

3) Compression errors, as Bajaman notes.

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Post by bajaman »

bassbutler rev 1.7z
(72.31 KiB) Downloaded 178 times
Hello Tuck
I am still working on this but so far this is the revised schematic for the complete clean channel - the drive channel looks ok at this point except for the footswitch connection ;-)
Anyway here is the revised clean channel tone control and compression section - the DI out was fine - i am assuming the resistors are the correct values and used the same as your original schematic - more to follow in due course - i am a newbie to Kicad, but so far i like it !
cheers bajaman
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Post by bajaman »

Okay - i have drafted and checked the complete board now so this schematic (rev 1a) should be correct, however there are still some unknown resistors that need to be measured or guesstimated, they are: R33, R38, R39, and R49 - again i am assuming that Tuck has labelled all the other resistors with the correct values - they look ok for the circuit to work ;-) C26 is 3.3nF
I think i have done as much as i can at this stage, not having it physically in front of me
cheers
bajaman
bassbutler rev 1b.7z
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Post by bajaman »

and - redrawn to make filtering clearer
cheers
bajaman
bassbutler rev 1c.7z
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Post by Manfred »

Hi Bajaman,
is a zip file insteed a 7z file possible?

cheers
Manfred

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Post by blackboarcult »

there there :)
Will have to install Kicad...
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bassbutler rev 1c.zip
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Post by bajaman »

just in case you were wondering - the led is a four pin device - pin 1 is red anode ( compression level indicator), pin 2 is common cathode, pin 3 is blue anode (when drive channel is disengaged) and pin 4 is the green anode (when drive is engaged)
cheers bajaman
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Post by bmxguitarsbmx »

Nice work Bajaman and Tuck!

So, the output DR +CL mixer is just a passive resistive mixer? Seems silly, but the big guys do silly things as much as the rest of us do I suppose. R78 on IC4a just seemed to me to be a good place to insert the DR (non-inverting pin3)

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Post by tuck »

Regarding R33, R49, R38, R39
resitorsinquestion.png
I will send a picture with all resistors so you can recheck.
It will take some time, I am sick but tomorrow I will send them.

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Post by bajaman »

getting closer - R33 = 1M, R49 = 1M, R38 and R39 are both 2.2M (2M2)
amended file plus interim pcb top and bottom layers attached
cheers
bajaman
bassbutler rev 1d.zip
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pcb top.GIF
pcb bottom.GIF
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