The Sentient Machine

3/8/2016

Update 2016-03-16: I added a vero layout

It has been a slow start to 2016, but a few new projects are finally coming together. Here's a new DIY project - The Sentient Machine.

It's a resonant lowpass filter modulated with an LFO. It has a couple of different voice settings, a standard wah sound and a special vowel sound. At slow speeds it makes a cool spacey sweeping sound reminiscent of a phaser, and at minimum depth and medium speed it almost sounds like a tremolo.

This circuit is pretty advanced, but it's a straight forward build. The PCB is made to fit inside a 125B enclosure.

The madman Savvas (@tagboardeffects) submitted a vero layout. Thanks! Please note that it's not yet verified.

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Download File

PCB avaliable in the shop

15 Comments

jesse funk

3/13/2016 01:35:52 am

i would like to purchase this in a kit. will that be possible?

Fredrik Lyxzén link

3/14/2016 06:26:26 am

Hi Jesse,
Full DIY kit will be avaliable from Musikding.de shortly. I don't know exactly when, so just keep checking their website. :)
Cheers, Fredrik

Schenkenstein

5/2/2016 07:22:09 pm

Just finished the sentient machine. It sounds fantastic. I'll post photo as soon as I finish boxing it. Thanks

Fredrik Lyxzén link

5/5/2016 12:20:43 pm

I'm glad you like it! I would love to see your build when/if you have the chance to share a pic. :) Cheers / Fredrik

Schenkenstein

5/5/2016 01:38:20 pm

How do I upload a picture of my build?

Schenkenstein

5/30/2016 07:03:20 pm

Here is a demo of my build. http://youtu.be/gq54pCKSq0s

Schenkenstein

5/30/2016 07:04:58 pm

Sorry. https://m.youtube.com/watch?v=gq54pCKSq0s

Fredrik Lyxzén link

6/1/2016 08:17:14 am

Hi Schenkenstein,
Thanks for sharing! Great demo and cool looking build :)

pink jimi photon link

1/14/2017 03:33:03 pm

hey fred,
i built this FINALLY last nite.. been on the road and no time to get my build on!!! it went together great, beautiful board and layout, possibly the cleanest thing i've ever built. fired up perfectly right out of the gate, too... outstanding. sounds just like your demo!
BUT i am having an issue not with "ticking" but a thumping sound when the voice switch is to the left which i assume is the formant position.. any ideas as to what i may look for to track this down?
i'm thinking it may be the wire carrying b+ to the board, as i have it kinda snaked over the top of the board (solder side with the knobs facing down)... i have it running along the side of the enclosure (your drilling template is right on the money btw) and it's kinda close to a couple caps... gonna play with it and try and sus it out but thought i would ask and submit a build report... this is my fav mod box yet. i may put it in a bigger enclosure so i can squeeze in another jack to hack an expression pedal on the speed.
but anyway i look at it a great project that sounds killer, thanks bro!!
soon as i get some funds i'm gonna try the into the unknown next.
hope ya have a great year, and thanks again brother!
peace
jimi

Fredrik Lyxzén link

1/15/2017 04:27:21 pm

Hi Jimi,
Thank you for the build report. I'm glad you like it. :)
I've had the thumping sound aswell in a recent build, and it went away when I swapped IC4 (the dual op amp) for another type of opamp. I can't remember which type I ended up with and I don't have that pedal any more.. So you can just try swapping it for just about any other type of dual opamp to hear if it makes a difference. If not, i'm not sure where to being looking. Maybe the pwm oscillator could also cause thumping if it's running out of spec. I can guide you through troubleshooting via email if you contact me at parasitstudio@gmail.com.
Anyway, I hope you will post about it in one of the forums. :)
Best regards / Fredrik

pink jimi photon link

1/16/2017 11:49:53 am

thanks for the quick response sir!
i bet ya that is the issue... i think i subbed an ne5532 or a tl084 for the specced part. i will have a play with it and report back.
i will most definitely post on the forums with video as soon as i can, and will post back here as well my friend.
wishing you health wealth and wisdom
LLAP
jimi

Schenkenstein

1/16/2017 06:51:45 pm

I have a feeling it has to do with the tl062. It is supposed to be quieter that a lot of others. I've heard before that switching it for another tl062 would help. Also, try to rearrange the input and output wires away from the tl062 chip.

pink jimi photon link

1/16/2017 08:31:05 pm

thanks schenkenstein,
i can try it. i haven't had a chance to get back to my bench yet. but the ne5532 should actually be quieter than a tlo62. not that that means much ;)
the input and output wires are no where near it, they come off the pcb and go to the switch maybe a half inch away.
i DID route the b+ over the solder side of the board on top as ya open the lid, i may have to add a different wire and dress it along the bottom of the enlosure. lead dress is funny sometimes.
i gotta old fender princeton... if one of the wires gets moved internally when working on it, suddenly it goes from an amp to a theremin ;).
i will mess with it hopefully tomorrow and report back. thanks for the support! ;)

pink jimi photon link

1/18/2017 11:56:33 am

ok i got to mess with this last nite before my gig. i tried all the dual opamps i had on hand:
ne5532
tl082
tl072
tl062
ha17458
4558
lm358n******
the lm358n worked the best, lowest noise, less distortion when playing dynamically, and a somewhat cleaner filter sound since it's fairly low gain.
the "thumping" only happens with both knobs dimed, which i will likely not need anyways (tho i am planning on mounting this inside a crybaby shell and replacing my univibe with it).
i found on the higher gain dualies that it tends to distort quite a bit when i hit a power cord, mostly on the side with the increased feedback.
the lower gain really seemed to help in this case, and may be worth investigating. no real change in the filtering or output, just less breakup. also didn't notice the high speed opamp as much.. at some settings with fuzz in front of it you can hear the filters almost stepping thru the frequencies a little with both knobs dimed. i don't hear it anymore with the lower gain opamp.
i did change the lead dress, i think it's cuz where i mounted my power supply jack is too close to the traces for the speed knob. tight fit in a 125 for sure! ;)
anyways, those are my findings for now... thanks brothers!!
jimi

Fredrik Lyxzén link

1/19/2017 04:33:33 am

Hey Jimi,
Thanks for sharing your findings! I'm happy you found one opamp that worked alittle better than the others. I also get a bit of distortion, especielly with my strong output humbucker guitar. I think the resonant peak is just too strong and doesn't have enough headroom for it to be clean. It would probably help to run the pedal at 18 to increase the headroom. Don't try that however.. it will screw up the pwm oscillator. But maybe something I should add (a chargepump) for the signalpath stages in a future revision. :)
cheers / Fredrik

The Sentient Machine

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