My build progress

[Jos]

I would not expect 10uF capacitors to be problematic in this way (unless they are shorted), so I’m sort of guessing here. The diodes and resistors would not cause such behaviour either.

[eric]

Well, I’m not so sure about the effect of 10uF on each of 10 modules (total over 100uF) on the 7812…
The datasheet says… 0.1uF for 78xx, 1.0uF for 79xx.
Also, the datasheet recommends clamping diodes when using a bipolar supply (“protects the regulator from output polarity reversals during startup”), and shunt diodes in some situations (which we may hit with such a big output capacitance…)

Peoples are questioning the utility of those caps on the modules, as I already pointed out here :

Jtommi's first modular - Progress

The caps are for power “filtering”/“smoothing”/“conditioning”/whatever people call it… A typical power circuit for a module looks like this : [Untitled] (PWR_FLAG are KiCAD’s way of telling that’s the point power enter the circuit, they have no physical counterpart) OK, I still have BAT85 in my schematics… but in real life I put 1N5817 there, they have better specs for this job. They are for reverse polarity protection. The 10uF are close to the power connector. They are a sort of energy …

I still have no opinion on their usefulness/harmfulness.

Just make some tests with caps on your PSU but no modules…

[analogoutput]

This maybe merits its own topic rather than a discussion here…

PSU startup problems

From the My build progress topic: and a couple more people spoke up saying they’d had similar issues with Frequency Central/MFOS style wall wart supplies. Seems worth breaking out to its own topic. It’s not always on -12V. It does seem it’s the regulator shutting down due to overcurrent, probably associated with a capacitor which once it starts charging up pulls less of a load, so that restarting is successful. Is it the 10µF (or whatever) bypass capacitors on the module power rails? Is it …

[Dud]

@Jos

I’m guessing all of you are using non switching power supplies?

not on the wallwart power supply but i have a switch between it and the FC

@analogoutput

I do use diodes in series and not 10R resistors, could that make the difference?

in my case, no 10R and no diode

and sometime if i remember this has already happened on +12 too

[analogoutput]

Finished up the Neuron/Difference Rectifier

[Dud]

Very prolific at the moment !
It’s building at lightning speed, I suspect the Doctor has a Tardis

[analogoutput]

Oh please, for you this would be described as a Monday.

I did the PCB a week or two ago, just had to make up the front panel and wire it. Everything worked. I mean, I think everything worked. Since I have only a vague and possibly backwards idea what the neuron section is supposed to do I’m not sure it’s actually doing it, but if not it’s doing something equally bizarre, and the behavior changes when you turn the knobs, so I’ll take it.

[saint_et_moudulard]

Really like your panels designs, pretty and clean work !

[sebastian]

I agree! I also like how you honor the original circuit designer while keeping your graphical style!

[konthaar043]

Inspired by @analogoutput 's power indicators, i decided to make power distribution boards like this.

My case is very shallow so it was very hard for my big hands to plug the power headers in. Now i can just lift this module out instead.

I’m going to make a +/-150 volt supply next, for tube modules. It will be powered from my ultra beefy 12v supply. This way i don’t have to make long runs of high voltage through my system

[Bpbby]

Ahahaha, doing exactly the same thing here

[analogoutput]

Can’t stop won’t stop

AO joystick Kosmo module

This is a Kosmo format synth module that provides an interface for an analog joystick. The X and Y outputs provide control voltages that vary with the horizontal and vertical positions, respectively, of the joystick. [front] There are range control pots for X and Y. These adjust the width of the control voltage range. With the width fully clockwise the control voltage range is about 10 V end to end. There also are offset control pots. These add a DC offset of between -5 V and 5 V to the outp…

[analogoutput]

Trigger sequencer shows definite signs of working!

[Dud]

It is beautiful, always very practical this type of sequencer, it makes me want to try it

[BlackDeath]

Fixed my kracken kick drum (@Dud loves those resistors directly connected to jacks, but they’re a bit fickle…), then made an out-of-spec 2cm passive multiple with space for a passive LPG another day, and a 1cm blank for a gap in the top row. Hooked them all up to Ableton and my launchpad… we’ve got a serious jam machine now.

As the actress said to the bishop… I’ve got a full box!

[JaggedNZ]

Finally got my 2600 grey meanie up on a stand, freeing up much needed space for the rest of my gear that’s been sitting on the floor. The base is an old TV stand the rest was random pieces of pine. Plan to tidy the woodworking up and paint it (probably black) at some point but good enough for now.

Thanks @analogoutput for the dimensions they really helped solidify my plans.

[analogoutput]

And the last (whew) of this round of modules. I’m particularly pleased with how this turned out!

AO G.E.A.R. Sequencer (rhythm generator)

This is a voltage controlled trigger sequencer or, perhaps a better term, trigger sequence generator. It can function as a Euclidean rhythm generator, but it can also create other rhythms via different means. It is designed in Kosmo format, though it can presumably be adapted to any other format capable of supplying enough positive voltage for 5 V voltage regulators. What it does Rather than sending triggers in a sequence that is completely specified by the user, the G.E.A.R. Sequencer creates…

[fatboab]

Been feeling under the weather the last few days, so ended up with a bit of free time yesterday afternoon. I was watching various @lookmumnocomputer YouTube videos to drown out the sound of the ultrasonic water bath, as it cleaned loads of vinyl. Inspired, I thought it was about time I sorted out my triple super simple oscillator breadboard experiment.

I removed all the wires, took out most of the resistors, replaced the 100K pots (and parallel 2x 4K7 resistors) for 10K pots, then put all the wires and correct resistors back. Once that was done and confirmed working, I decided to start following along to @moritzklein’s DIY Synth VCF YouTube videos. I got as far as the 2nd order passive filter, and I now have questions…

[d42kn355]

Finished up preserving an old circuit of Peter Blassers (early 2000’s - there are about 25 boards in existence - an old collector sent me his to copy and archive)

This fits in well with the Fources boards I preserved and the Dubernator Filter that I preserved.

This circuits uses 2 Piezos, 4 Buttons, and 2 CV Output/Gesture of the piezo S-curve.
3 Inputs - A, B, and AB (Mix)
3 Outputs - A, B, and AB (Mix)

Really excited to finally get one of these in my hands for myself!

[nschagen]

I am often having something similar, but in my case only the -12V rail works and the +12V does not actually give any power. When I unplug my power, it takes a few seconds and then suddenly all my modules get some power on the +12V line before the filter caps run dry. When I reconnect the power, everything works again. Its super weird and I don’t know what causes this (I’m using the Frequency Central Power Supply).