Recursive Machine Build Thread

[folpon]

Hm... I measure only 3v on the pads in my RM's power section. LED doesn't light.

Can't see a bridge anywhere, I've double and triple checked all the components are where they should be. Time to troubleshoot...

[bezier]

Also, when i run it with batteries, the voltage test point are nowhere near +5/-5v. Has anyone tested this? The only thing i found was the inductor, as i used a 10uh instead of 1uh, as discussed earlier in this thread.

The test pads are confusingly labeled. The third pad is the ground, not the first. So 1 and 3 and 2 and 3 are the tests you need. I also used the 10uh inductor and got about +/- 4.9v on the test pads.

Thank you for chiming in again. Well ghe pads show +/- 5v with external power, so i'm even more confused about the outputs with batteries. I probably measured something wrongly here, will try it again.

[japes]

Also, when i run it with batteries, the voltage test point are nowhere near +5/-5v. Has anyone tested this? The only thing i found was the inductor, as i used a 10uh instead of 1uh, as discussed earlier in this thread.

The test pads are confusingly labeled. The third pad is the ground, not the first. So 1 and 3 and 2 and 3 are the tests you need. I also used the 10uh inductor and got about +/- 4.9v on the test pads.

Thank you for chiming in again. Well ghe pads show +/- 5v with external power, so i'm even more confused about the outputs with batteries. I probably measured something wrongly here, will try it again.

You might try the battery clips on the negative side. The battery casing is designed to be just a smidge tight to hold the batteries in, so it's possible the force of putting the batteries in might make the joint a little inconsistent. I found that to be the case with mine - it measured great out of the gate but needed some touchup after a bit.

[Nelson Baboon]

out of curiosity - anyone build these for us poor non-diy folks?

[TheTimeEater]

Hm... I measure only 3v on the pads in my RM's power section. LED doesn't light.

Can't see a bridge anywhere, I've double and triple checked all the components are where they should be. Time to troubleshoot...

You ever figure this out? I'm having the same issue

[folpon]

Hm... I measure only 3v on the pads in my RM's power section. LED doesn't light.

Can't see a bridge anywhere, I've double and triple checked all the components are where they should be. Time to troubleshoot...

You ever figure this out? I'm having the same issue

Reflowed the power section. Then I got 5 on the pads. But LED still doesn't light, and RM doesn't operate. Think I might have burnt a voltage regulator. Or maybe the power switch is bad; voltage flows no matter which position the switch is in. So, sorry, still unclear here.

[nitazine]

Howdy,

I'm building the RM and was wondering if there are schematics/measurements for a front panel? Something I could use for front panel express. I was thinking of then building a wooden case for it.

Cheers

[japes]

Howdy,

I'm building the RM and was wondering if there are schematics/measurements for a front panel? Something I could use for front panel express. I was thinking of then building a wooden case for it.

Cheers

Nothing publicly available other than the build guide which I'm sure you've already looked at. you might ping jon by email, he's fairly responsive.

[kroffe]

I building this now and build the reverb yesterday with a mod posted by jon elsewhere.
It changes the Dry/Wet knob into a feedback knob for the reverb instead (since you already can set the wet amount in the mixer).

Highly recommended!

[Heavy Metal Kid]

Here's a time-lapse of my build, maybe it is of use to someone.

[mount_curve]

Opted for the 3D printed case but even after some sanding of the corners of the case and pcb it's a pretty tight fit lengthwise when both boards are in, enough deflection when inserted that I'm worried about cracked solder or fracturing if hit too hard from a drop sort of deal, I have to push pretty hard for them to pop in and I really don't think I'll be able to sit them completely parallel while fully assembled with the headers in without significant difficulty.

Anyone know exactly what this case is made of? I'm tempted to anneal it properly in an oven with the boards in place for everything to settle in a bit.

Hell, I work in plastics - could commandeer the annealing oven at work for a few hours overnight if I needed to be a little more exact. I worry about the handle deforming, though.

My plastics-fu says it smells like Nylon - certainly pretty hard, acts like it when cut.

Might just continue to flat hand-sand the short ends until it isn't a PITA

[delayed]

3D printed of ABS
plastic per the BOM notes

I can not get mine to fit either

[mount_curve]

3D printed of ABS
plastic per the BOM notes

I can not get mine to fit either

See attachment for my very scientific method of working this out after getting tired of sanding

Place single washer stack on sideways baseboard heater at full clip so that RM sides do not directly touch surface hot enough to burn human flesh and melt ABS, flip around every minute or so to distribute heat evenly.

When heating bottom board, try both fully seated and pushed out to the ends of the legs.

Flip often, work boards in and out until a satisfactory looseness has been achieved.

LET COOL WITH BOARDS IN ON A FLAT SURFACE

big disclaimer: be careful with this, if you forget this thing on your baseboard for ten minutes you're going to come back to it looking like it's the LSD Recursive Machine

[kroffe]

To mount the boards in the case:
First mount the spacers on to the bottom board with the screws.
Then fit the top board in the case from above, followed by the bottom board from below as straight as possible. It's a tight fit, but the spacers should go into all four corners. Push it in as far you can.
Now you can start screwing the screws from above that just reach the stand-offs. When all screws are evenly tightened the boards will snap into place as long as you have mounted all pin headers according to the build instructions.

To easily un-mount the boards out of the case (for changing batteries) etc:
Use the t8 security torx screwdriver, untighten the screws nearly fully on the top side and then jam with force them into the holes - this will unpop the boards from each other. Then the rest is easy.

[Val]

I building this now and build the reverb yesterday with a mod posted by jon elsewhere.
It changes the Dry/Wet knob into a feedback knob for the reverb instead (since you already can set the wet amount in the mixer).
recursive reverb.png
Highly recommended!

Nice mod, thanks for sharing. Nice only if you use the machine on it's own, though?

[kroffe]

Nice mod, thanks for sharing. Nice only if you use the machine on it's own, though?

I’m not sure what you mean. Feedback mod still works with external signals and when patching the output of the reverb directly external?

[Val]

Nice mod, thanks for sharing. Nice only if you use the machine on it's own, though?

I’m not sure what you mean. Feedback mod still works with external signals and when patching the output of the reverb directly external?

I mean that it modify the "experience" of the machine, if you change the wet/dry knob into feedback knob, reverb will be always fully wet, right?
Then if patching externally, must use it as a send, not an insert. And if patching the RM differently (breaking normalled connections), same, how does the mixer wet dry thing works?

Sorry if I am being unclear, I haven't built it yet ... And seeing this mod, wondering if I should build it this way ?

[Hovercraft]

... And seeing this mod, wondering if I should build it this way ?

I built mine before the info on the mod came out, but I'm planning on doing the mod. I've always got the reverb turned fully wet, because as kroffe noted you can adjust wet/dry in the mixer. The reverb output is only normalled to the mixer--so it won't get fed back into the delay, filter, or distortion loops. You can think of the distortion unit output as the fully dry signal (with all circuits) and the reverb is an end of chain effect acting on the distortion output. Since you have direct output from the distortion (as well as points earlier in the signal chain) unit into the mixer, I can't think of any reason why you'd need the wet/dry on the reverb. The feedback mod adds something useful without taking anything away.

[japes]

hey all, another question about the power section.

I was getting correct voltage amounts on the test points, but for some reason the -5v output started giving me only a little voltage (~under -.5v). I think I may have powered the RM with a center positive, rather than center negative, power supply. I noticed after this happened that the diode in the power supply began heating up to an uncomfortable level, so I pulled it and replaced it and it is no longer heating up. However, I'm still getting -.5v or so on the -5v test point.

I'm assuming that the next step is to begin testing all the components between the power supply and the diode? Do I need to pull them from the circuit in order to test?

[mount_curve]

Wrapping my build up today, couple questions on the "options"-

a. Anyone have commentary on log vs linear for the LFO speed?

b. What did you use for the 1-47k on the reverb feedback control mod for best balance? Is 1k too hot?

c. Did anyone actually attempt using a different cap value for a slower LFO- or is slowing down the LFO more complicated than that? What did you use if so?

[ndkent]

I used a bigger cap on one LFO - I have to pop the lid to check, either 3x or 4x the value and it was quite a bit slower.

The one thing I wasn't happy about, which you may have noticed with the original value, is say you turn the pot to the top, adding CV from a jack will not make the frequency go up any further if it's set to the top by the pot already.

[kroffe]

I don’t have any opinions on LFO speed or speed range pots. But I noticed that the waveshape pots did not have much effect so I changed them to 1M on suggestion by Jon. Performance is better now, but still not perfect.