Recursive Machine Build Thread

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Re: Recursive Machine Build Thread

Post by Hovercraft » Sat Oct 10, 2020 10:21 am

Peake wrote:
Fri Oct 09, 2020 11:04 pm
Not sure if Jon updated the manual but he recommended to me, after the last indicated manual revision date, to increase the gain of the wet reverb by changing the 39K in the top section of the reverb (between the 1K and 10K) to 10K or less.
Thanks for posting this! I was thinking the gain on the wet reverb signal was too low. I'm closing in on finding a good micro usb jack so I can replace that blasted barrel jack, and easily use a battery pack. I'm thinking of building a case that fits a battery pack, and also includes a headphone amp circuit with a pot. These jacks are stiff--hopefully they loosen up a bit with use.

This morning is the first chance i've had to systematically explore the RM. I'm trying to memorize the semi-normalled connections, so I can have a better handle on playing the RM. With all the feedback loops--things can get super noisy fast. Nothing wrong with that--haha--but there's some great sounds when you have the feedback loops just on the edge. I like this little synth a lot--it reminds me of the Lyra-8, with the emphasis on feedback loops, distortion and dual PT2399 delays.

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Re: Recursive Machine Build Thread

Post by Peake » Sat Oct 10, 2020 12:01 pm

This is the power supply I eventually found, does anyone especially in the US have a better and less-expensive wall wart solution?
Hovercraft wrote:
Sat Oct 10, 2020 10:21 am
I'm closing in on finding a good micro usb jack so I can replace that blasted barrel jack, and easily use a battery pack.
That would be amazing!
This is not the place I'd imagined it to be.

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Heavy Metal Kid
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Re: Recursive Machine Build Thread

Post by Heavy Metal Kid » Wed Oct 21, 2020 9:17 am

I have a built unit for sale locally in Berlin. Have a look:

Last edited by Heavy Metal Kid on Fri Oct 30, 2020 12:36 am, edited 1 time in total.

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Re: Recursive Machine Build Thread

Post by synthcube » Wed Oct 28, 2020 3:15 pm

We are very pleased to report that the Recursive Machine bundles are in the shop now-- special thanks to Jon for the effort-- really one of the coolest little projects we have seen in a long time!!

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Re: Recursive Machine Build Thread

Post by ndkent » Sun Nov 01, 2020 7:27 pm

Looking at the Mouser BOM from the THC site - what I'm looking at it shows up as RM 3.0 on Mouser

I see a Bourns 10K trimmer 652-3362P-1-103TLF that I don't see on the PCB?

I see a bunch of different spec resistors, for instance 1/3w, 1/2w, 1200ppm - are there any through hole resistors that need a spec other than 5% carbon film 1/4w? I assume not but want to ask if I'm ignoring something.

I don't have the header parts ordered to look at them. I take it the pins are very long (part spec says 13mm) to cover the 18mm of the standoffs when connected. Shouldn't the male header be 2 instead of one row? or maybe the part does not exist as 2 rows with pins that length (I've not gone hunting)?

off the BOM
There is a mention in this thread of swapping longer shaft pots, any feedback using them, like harder to use the jacks or easier to damage than the shorter ones?

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Re: Recursive Machine Build Thread

Post by Peake » Sun Nov 01, 2020 7:38 pm

There is a single trimmer on the PCB in the amp section used to adjust the internal speaker level (blue, just below the speaker).
Screenshot 2020-11-01 182525.png
Screenshot 2020-11-01 182525.png (109.93 KiB) Viewed 289 times
It's very useful to know the snap-off male headers are keyed...one side of the plastic has a bump across the middle and the other side, a slot. Hold pairs together bump into slot when fitting into the PCB holes, makes it much easier. (The male headers come in single-row strips but with a lead trimmer can be snapped off to the required length. Do check out the ridge on one side and the slot on the other; if you hold them slot side to ridge side everything goes much more easily.)
Last edited by Peake on Sun Nov 01, 2020 9:28 pm, edited 3 times in total.
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Re: Recursive Machine Build Thread

Post by Hovercraft » Sun Nov 01, 2020 8:38 pm

ndkent wrote:
Sun Nov 01, 2020 7:27 pm
...
off the BOM
There is a mention in this thread of swapping longer shaft pots, any feedback using them, like harder to use the jacks or easier to damage than the shorter ones?
I used the short shaft B100 pots for everything except the mixer, where I used long shaft A100 log pots. I think it makes it easier to control the mixer. I wouldn't use long shafts for everything.

Really enjoying the RM--love the range of sounds I can get out of this little synth.

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Re: Recursive Machine Build Thread

Post by cat_abyss » Fri Nov 06, 2020 9:55 am

Hey, did an anyone finish their build yet? Anyone wanna share some demos?

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Re: Recursive Machine Build Thread

Post by dankalmanson » Fri Nov 06, 2020 12:07 pm

ndkent wrote:
Sun Nov 01, 2020 7:27 pm
There is a mention in this thread of swapping longer shaft pots, any feedback using them, like harder to use the jacks or easier to damage than the shorter ones?
I used the longer shaft. I'm not sure if I misordered or I was given the wrong ones but I decided to go along with them. I think they are fine. It does not look as flush with the sockets but I can access the knobs fairly easily. It is a tight footprint and you for sure feel it when twiddlin' knobs. Especially if you are a giant human.

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Re: Recursive Machine Build Thread

Post by Wavy Davy » Fri Nov 06, 2020 4:54 pm

Just received the boards from Snythcube.
They arrived in a nice black box.
Ordered all the parts from the Mouser BOM (after substituting out of stock parts),
also ordered the extra parts from other sources.
Looking forward to building this, when the parts arrive next week.
Might make a custom hardwood case for it.

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Re: Recursive Machine Build Thread

Post by Wavy Davy » Sat Nov 14, 2020 8:03 pm

Finished my build, and after removing a solder bridge and turning around a transistor that got installed backwards, it works great.

I have small hands and it is a squeeze, to get my fingers in between the cables, to turn the knobs.
That said, I have spent hours on the couch playing with it.
Patching is fun, the jacks were stiff at first but soon broke in. (maybe a dab of WD-40 on a Q-Tip, stuck into the jacks, would help that).
The little speaker allows you to make noise with it anywhere, but with a fair amount of distortion.
If you want to hear the sound clearly, you must plug it into an amp.
If you were wondering.....When you plug into the Recursive's 1/8" mono output jacks (wired in parallel), it disconnects the internal speaker.

When I built mine, I put a piece of cardboard on the bottom (held on with the 4 mounting screws), to protect the circuit board from short circuits.
I installed new NmH batteries in it, and recharge them, without removing them from the case (which is reallllllly hard!).
I use a battery charger made for Radio Control hobbyist, that can charge all kinds of battery combinations, using aligator clips.
I simply clip onto the battery terminals protruding from the bottom of the circuit bd., and charge them in place.
(NOTE: Maybe you could solder the battery clips onto the bottom of the PCB, and mount the batteries on the outside, not between the two PCBs.
Then just make the case a little deeper to accommodate the batteries, (and bigger speaker)

I also modified a 5V power supply to use with the Recursive when I'm in the house.
Had to cut off the existing plug because it would not fit the 2.5 sized Jack on the recursive.
Replaced it with bigger plug, and reversed the polarity, because the Recursive requires a center negative connection.

The first mod I will make (I already did the reverb mod), it to add a headphone jack to the case, so that when I plug in 1/8th inch stereo headphones, it disconnects the internal speaker.
As it is, the mono outs, can not drive headphones.
I want to be able to sit anywhere and play with this using headphones (it already has batteries, and is portable).

Wondering if I can get my hands on the 3D printer file for the case.
Would be fun to print one in another color, and/or redesign it, to move the batteries off the pcb, into the case, for easier swapping.
Or, could you solder the battery clips onto the bottom of the PCB, and mount the batteries on the outside, not between the two PCBs.
Then just make the case a little deeper to acomodate the batteries, (and better speaker).
Could also redesign, to fit a bigger speaker too. Lots of possibilities.
I'm also considering making a nice hardwood case for it.

And designing a paper overlay with color coding for the different sections, labels of what signals are normaled to the inputs, and to help distinguish between audio, and CV in/out jacks. Although it is pretty logically laid out, and I am starting to have it memorized after playing with it for a few days. Maybe just print a cheat sheet, and tape it to the bottom.

This could also be the heart of a diy custom build, where you make your own front panel, with larger, more spaced out knobs.z

Happy trails.....

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Re: Recursive Machine Build Thread

Post by Hovercraft » Mon Nov 23, 2020 4:38 pm

Good to hear there's a few more recursive machines in the world! Here's a short track with the rm as the only voice. some light fx on the first half, but otherwise 100% rm. I'm controlling it with an 0-Ctrl, and highly recommend the pair.


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Re: Recursive Machine Build Thread

Post by cat_abyss » Tue Nov 24, 2020 6:15 am

Hovercraft wrote:
Mon Nov 23, 2020 4:38 pm
Good to hear there's a few more recursive machines in the world! Here's a short track with the rm as the only voice. some light fx on the first half, but otherwise 100% rm. I'm controlling it with an 0-Ctrl, and highly recommend the pair.

Ohhh yes! (Thanks for sharing!) Love those chimes... This is one RM?

(And this means it accepts euro voltages, right?)

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Re: Recursive Machine Build Thread

Post by Hovercraft » Tue Nov 24, 2020 12:35 pm

cat_abyss wrote:
Tue Nov 24, 2020 6:15 am

Ohhh yes! (Thanks for sharing!) Love those chimes... This is one RM?

(And this means it accepts euro voltages, right?)
Thanks! The track is 90% a single live take with one rm. After I cut down the (much) longer take, I added 3 or 4 fairly short and subtle clips on top of the original track (taken from a couple other rm recordings made on the same day). So a small amount of multitracking--nothing elaborate.

The rm uses 0-5V control voltages, although a few 8V max outputs from the 0-Ctrl aren't causing any harm.

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Re: Recursive Machine Build Thread

Post by ndkent » Wed Nov 25, 2020 11:21 am

Have we confirmed that one can use a +5vdc universal adapter with a reversible tip or does one need a -5v dedicated one

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Re: Recursive Machine Build Thread

Post by Hovercraft » Wed Nov 25, 2020 11:30 am

ndkent wrote:
Wed Nov 25, 2020 11:21 am
Have we confirmed that one can use a +5vdc universal adapter with a reversible tip or does one need a -5v dedicated one
Any 5V DC power supply of at least 0.5A will work. A reversible tip is fine, although I just cut and soldered an adapter so it was center negtive.

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Re: Recursive Machine Build Thread

Post by Strezza » Sun Nov 29, 2020 4:29 pm

Soon done with mine. But there is one thing I'm struggling to understand. Power-section has two fixed inductors - one 10u and one 1u according to the build manual and printed on the PCB.
THC Mouser Bom one the other hand - has 2 10uh fixed inductors.
THC BOM says "10uH" and "1u".
I can't find any "1u" fixed inductors on Mouser.
Anyone know what to do here?
recursive machine power module
recursive machine power module

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Re: Recursive Machine Build Thread

Post by Hovercraft » Sun Nov 29, 2020 5:51 pm

Strezza wrote:
Sun Nov 29, 2020 4:29 pm
Soon done with mine. But there is one thing I'm struggling to understand. Power-section has two fixed inductors - one 10u and one 1u according to the build manual and printed on the PCB.
THC Mouser Bom one the other hand - has 2 10uh fixed inductors.
THC BOM says "10uH" and "1u".
I can't find any "1u" fixed inductors on Mouser.
Anyone know what to do here?
The BOM is correct--both inductors should be 10 uH. :tu:

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Re: Recursive Machine Build Thread

Post by Strezza » Mon Nov 30, 2020 2:02 am

[/quote]

The BOM is correct--both inductors should be 10 uH. :tu:
[/quote]

Great, thanks!
There is also a electrolytic capacitor (polarized) marked 150u on the pcb and in the build manual - but a 120uF in Mouser Bom.
Also ok to use the 120uF from Mouser Bom?

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Re: Recursive Machine Build Thread

Post by Hovercraft » Mon Nov 30, 2020 2:24 pm

Strezza wrote:
Mon Nov 30, 2020 2:02 am
The BOM is correct--both inductors should be 10 uH. :tu:
[/quote]

Great, thanks!
There is also a electrolytic capacitor (polarized) marked 150u on the pcb and in the build manual - but a 120uF in Mouser Bom.
Also ok to use the 120uF from Mouser Bom?
[/quote]

Yes, it's a decoupling cap, and you should go ahead and use the 120uF--either value would be fine.

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Re: Recursive Machine Build Thread

Post by Oscilloclast » Mon Nov 30, 2020 6:35 pm

I have two questions I'm hoping someone can answer:
1 - There was mention of a reverb feedback mod, anyone know what it is?
2 - Anyone figured out how to slow the delays down (I love the sound of PT chips breaking up). I'm currently just running -5v into the modulation input but there has got to be a way to slow them down more.
Thanks,

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Re: Recursive Machine Build Thread

Post by Peake » Mon Nov 30, 2020 8:51 pm

Jon mentioned to me there's a way to change the reverb resistors so the pot acts as a feedback control but the output is then always wet and you have to use the mixer for blending. Said he has a diagram but I didn't ask for it; hopefully he'll provide it if someone requests it.
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Re: Recursive Machine Build Thread

Post by Rex Coil 7 » Mon Nov 30, 2020 9:10 pm

~shudder~ .... yikes! ... some microphones are so good that video narrators often ~feel~ as if they are an inch from your ear, nearly whispering (or sounding like they've been bongin' all day with smoke-throat) right in your ear.

IT'S FRIGGIN CREEPY!!!!!

There's some synth/demo vids that are WAY worse than this'n ... some of them are like some serial killer on a subway sitting right next to you (RIGHT next to you) sortof whispering in your ear and telling you all the crappy things he's going to do if you make a single sound ... as the tip of his knife blade is pressed a little harder into your side to place emphasis on his intentions. DAMN MAN!! Get off my cheeks!!

The demo/release video at the beginning of this thread is right there .. it sounds like he's so close ... too close ... boundaries yo!!!!!!!! :lol:



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Re: Recursive Machine Build Thread

Post by japes » Thu Dec 10, 2020 11:36 am

My PCB gets here today, and all the parts have been waiting! I'm super excited. How long does the build take? Should I be able to get to it in one evening?

Also - this will be totally compatible with eurorack modules, correct? Since I ordered my PCB I've fallen down the eurorack hole...

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Re: Recursive Machine Build Thread

Post by Hovercraft » Thu Dec 10, 2020 3:05 pm

japes wrote:
Thu Dec 10, 2020 11:36 am
My PCB gets here today, and all the parts have been waiting! I'm super excited. How long does the build take? Should I be able to get to it in one evening?

Also - this will be totally compatible with eurorack modules, correct? Since I ordered my PCB I've fallen down the eurorack hole...
Cool! The build will take more than an evening--highly advise not rushing it. Take your time and do a good clean build. I built mine over the course of a week. The RM is compatible with eurorack--keeping in mind, the control range is 0 to +5V, it doesn't work on negative voltages, but won't be hurt by -5V. Attenuate and offset as necessary with euro signals.

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