madbeanpedals::forum

Projects => Build Reports => Topic started by: Stomptown on December 14, 2020, 02:31:02 AM

Title: Engineer’s Thumb
Post by: Stomptown on December 14, 2020, 02:31:02 AM
I built one of these years ago on the awesome PCB offered over at JMK PCBs and regrettably sold it to fund another project.  Mr Bean PIF'd me a 5-knob proto iteration, which I modded it back to stock specs in order to use the toner transfer I already had printed up and avoid placing an order for more pots.  I'm a less as more kind of guy anyways so all the knobs would've been overwhelming for me anyhow!  Thanks again Brian for the awesome PIF and to Leevibe for the knobs, which look pretty great IMO.  And thanks to you guys for taking the time to look.

Jon

(https://uploads.tapatalk-cdn.com/20201214/649d8f3e0d649b078794d5a55cfe7268.jpg)

(https://uploads.tapatalk-cdn.com/20201214/a5493fdf519547e33f0174860b278046.jpg)

(https://uploads.tapatalk-cdn.com/20201214/589422823a1c8085dcb035c3c121cd7e.jpg)
Title: Re: Engineer’s Thumb
Post by: Thewintersoldier on December 14, 2020, 02:41:26 AM
man, your builds are always a treat. The etch on the enclosure is great as always, but the wiring on the inside is always what does it for me. So clean and uniform, the wiring is a work of art. What brand wire are you using?
Title: Re: Engineer’s Thumb
Post by: Stomptown on December 14, 2020, 02:51:29 AM
Thanks!  I really like the pre-bonded 24awg wire that Small Bear sells but I've been out if that stuff for quite some time. I also really like 26awg solid core but you've got to be really careful not to move/bend the wires too much. I recently ran through a spool of that that I picked up at Frys electronics.  What you see here is 22awg 600V stranded wire intended for guitar amps that I purchased at tube depot.  It looks good but it's not close to ideal for pedal building.
Title: Re: Engineer’s Thumb
Post by: cooder on December 14, 2020, 02:56:20 AM
Top notch awesomeballsy, Jon! What a great etch and overall execution!

I'm currently working and fumbling on a Engineeers Thumb design and there's a few different schematics around by the looks, whcih one did you use for this and does it all work as expected? I'm shooting for a 5knob version btw.
If you have a link to schematic that you found to be working for you that would be greatly appreciated and all...
Title: Re: Engineer’s Thumb
Post by: Stomptown on December 14, 2020, 03:05:56 AM

Quote from: cooder on December 14, 2020, 02:56:20 AM
Top notch awesomeballsy, Jon! What a great etch and overall execution!

I'm currently working and fumbling on a Engineeers Thumb design and there's a few different schematics around by the looks, whcih one did you use for this and does it all work as expected? I'm shooting for a 5knob version btw.
If you have a link to schematic that you found to be working for you that would be greatly appreciated and all...

I'm not sure which schematic Brian referenced but it seemed to agree with the JMK schematic, which I used to mod it back to stock specs. It does work as expected. 
Title: Re: Engineer’s Thumb
Post by: cooder on December 14, 2020, 03:17:26 AM
Hmmm... just checked out the JMK schematic and it uses the CA3080 instead of LM13700 that you have and it's only listing the two controls.
Will have to do some more checking up on what's floating around there, thanks for quick reply!
Title: Re: Engineer’s Thumb
Post by: gordo on December 14, 2020, 01:05:11 PM
I love how the wiring has a graceful sweep to it, like it just fell in on it's own accord.  Mine always looks like it went in kicking and screaming :-)
Title: Re: Engineer’s Thumb
Post by: Tremster on December 14, 2020, 02:09:55 PM
Quote from: cooder on December 14, 2020, 03:17:26 AM
Hmmm... just checked out the JMK schematic and it uses the CA3080 instead of LM13700 that you have and it's only listing the two controls.
Will have to do some more checking up on what's floating around there, thanks for quick reply!

Isn't the inventor's schematic the proper official one?
http://www.valvewizard.co.uk/engineersthumb2.html (http://www.valvewizard.co.uk/engineersthumb2.html)

Here's another PCB with a schematic in the build doc:
https://shop.pedalparts.co.uk/Engineers_Thumb_Compressor/p847124_19924891.aspx (https://shop.pedalparts.co.uk/Engineers_Thumb_Compressor/p847124_19924891.aspx)
Title: Re: Engineer’s Thumb
Post by: Bio77 on December 14, 2020, 06:07:05 PM
Your builds are always so pro, top shelf!  8)
Title: Re: Engineer’s Thumb
Post by: cooder on December 14, 2020, 06:57:07 PM
Thanks for the links, Tremster! I do have now a few slightly varying schematics and will puzzle a version together with those, cheers.
Even valve wizard himself has now a latest version here:
http://www.valvewizard.co.uk/engineersthumb4.html (http://www.valvewizard.co.uk/engineersthumb4.html)