Earthquaker Devices - Bit Commander  [traced]

General documentation, gut shot, schematic links, ongoing circuit tracing, deep thoughts ... all about boutique stompboxes.
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gaffled
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Post by gaffled »

I had only limited time with one and was able to take this pic and write down all the component values. I took a pic of the values I wrote down, just ask if some cant be seen. I wish I could have taken out the pcb and got a trace side pic but it wasn't my pedal and they wouldn't let me. Maybe someone else can get a trace side photo or from the components piece together how it works.

---dead links removed----

ieatyouforbreakfast
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Post by ieatyouforbreakfast »

Just bought the pedal. Anyone at all interested in gutshots?

What I remember seeing in there is a transformer, two LM386s and some other cool stuff.

smurfberry
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Post by smurfberry »

The traces are covered by the white laquer on the board, on both sides. The circuit can still be traced, but it's a bit hard to do from just photos.

Image

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Nocentelli
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Post by Nocentelli »

So maybe it is an input buffer (left opamp of TL072) which splits the signal to the octave up generated by LM386, transformer and diodes like Bob's Octavia below, with a parallel send to the CD4040 (is it? can't read the marking well enough) for the one and two octaves below like the Robot devil, then back to the other half of the TL072 for an output mixer.

I'm guessing the 386 has it's output tapped before the transformer to the B100k pot to provide the fuzzy "base" guitar (and maybe the send to the 4040 comes from here too), and I assume the filter control is just the 5k pot and the red cap to ground on the output for treble roll-off, just before the A100k level pot. Quite a cool little package, a bit like a dirty, much lower parts count version of the excellent Pearl OC-07 Octaver.
BobsOctavia.jpg
Robot Devil two octaves down -
https://www.freestompboxes.org/viewtopic ... obot+devil
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

smurfberry
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Post by smurfberry »

The CMOS IC is CD4024BE, used in Slacktave and 4ms Nocto Loco

kroaton
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Post by kroaton »

Here's a better gut shot I found (still useless)

I've been messing around on the breadboard using the values I transcribed from the gut-shot and Nocentelli's ideas and it's getting quite close to the original, though I'm starting to think that there are better circuits out there that do the same thing.

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azrael
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Post by azrael »

I'll try and open up mine sometime soon. Maybe I won't have a white silkscreen on it.

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Nocentelli
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Post by Nocentelli »

Component-labelled gunshot and schematic at tagboardeffects.blogspot.co.UK


http://guitar-fx-layouts.42897.x6.nabbl ... 802579-237

http://guitar-fx-layouts.42897.x6.nabbl ... 802579-237

I've posted links to the images, I can't seem to link to the thread containing them or subsequent discussion directly, hope IvIark doesn't mind.

I wonder if the transformer and 4024 could be replaced with the bjt phase-splitter from the Green ringer and 4040? (i have the latter but not the former)
Steven_M wrote: 21 Jan 2011, 17:52
biffa wrote: Sorry,but u r not the only member here

I'm not? Well fuck this site then. I only want meaningful conversations with myself.

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tabbycat
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Post by tabbycat »

link to the post at gfx here...

http://guitar-fx-layouts.42897.x6.nabbl ... 22775.html

unverified vero layout recently added.
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storyboardist
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Post by storyboardist »

Here's a perf and PCB layout of the Bit Commander. I used the same schematic TabbyCat posted above (which I believe is verified).

Image

kerbang
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Post by kerbang »

Can one just use the final two stages of a roger mayer octavia in place of the transformer? Cuts the cost a bit...

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Visualdistortion
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Post by Visualdistortion »

Does the chassis of the transformer need to be grounded? thanks
I wanna make it
I wanna make it wit chu
(again and again and again)

French... sorry ;)

kerbang
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Post by kerbang »

kerbang wrote:Can one just use the final two stages of a roger mayer octavia in place of the transformer? Cuts the cost a bit...
Short answer no.
Long answer:
Image

I'm no expert but I tried a few circuit configurations and in the end I gave up and tried throwing my madbeanpedals slambox in front of the octave stage of an RM octavia. And well, it works for me. Haven't socketed diodes yet so on the off chance someone actually wants to try this for some reason.. yeah do that. I used Germ ones off the bat so who knows what 4148 sounds like. D3 is just polarity protection. Oh and I went with a 47n instead of 100n. Maybe I should have gone lower.. Suggestions for improvements would benefit me. Put an LM386 with clipping before it and tell me if it makes an amazing IC fuzz octavia.

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Post by FausterCraster »

Schematic link is no longer working.
Anyone has the schematic picture pls ?

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