#164

As a follow up to this, if you look at a tear down (of a stock Volca), you’ll see the unit is made of two PCBs. The ports and jacks (sync, power, audio) all mount on the lower board to leave enough space between the panel and the PCB. Off the shelf/conventionally mounted jacks almost certainly don’t fit between upper board and the panel. This, combined with the large footprint (Vs the small female headers they use) would probably make layout as 2 boards even more tricky (meaning you’d probably need a different case and overall layout inside). I presume it costing more than the other volcas relates to the additional assembly cost (more than extra parts) and needing an extra PCB and new case design would add even more: manufacturability is a big consideration that one off DIY makers don’t have to contend with.

Without the extra board they would probably have to seriously compromise on the number of patch points available which seems like a poor trade off. Overall I think they did about as well as they could given the constraints, though I’d like to see Korg adopt midi over TRS ports, or even midi in and out on a single TRRS for future models to free a little more space.

#165

yeah, that is way beyond what I have the skills to do. The panel mount jacks and pots, I could do but soldering connections to the pcb…no way, the parts are tiny.

It is amazing how much Korg was able to get into the tiny box. That is one of the main reasons I was drawn to it in the first place; its is so small and cute.

Somebody will probably figure out a cool way to do it.

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#166

One possibility I considered was a “hat”. A PCB with male headers/jacks that exactly correspond to the panel that you push on top. This would only need the traces necessary to provide the jacks and would be completely non destructive. This poses a few problems that I can see. First of all: how do you access the pots? They could be make accessible directly, but once placed alongside full sized jacks this would be quite inconvenient. You may be able to add knob caps but I can’t really say for sure. Next would be visibility of LEDs; I don’t know that there are any on the panel, but the pots are illuminated and that conveys information you probably don’t want to lose. Finally it may be very hard to install. Getting a couple of rows of headers to line up is tricky enough: getting 50 disjoint header points plus the 5 ports to all line up at once seems very tricky, no matter how carefully you construct it (maybe it would be made in several pieces?).

You might be able to avoid this by having it stand off and installing a rat’s nest of wires in between, but at this point the type of break outs people have been discussing probably make more sense. I suppose you could make one that more closely matches the layout of the Volca and provides jacks for every patch point which you hook up with ribbons (lots of the patch points are in little groups, so it would make the wiring neater). Even then, all those connections would probably obscure the panel and make it hard to access the pots without a lot of careful routing. This also loses a lot of the charm of the device (compact and self contained).

All in all I think making a new case with all panel mounted controls and ports is the only way to end up with something that retains all the usability and consistency of the original. It might be a fun project for someone, but not something I’d be inclined to undertake.

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#167

I think it’s not that hard. A PCB with male headers that fits flat on the surface of the VM panel. The PCB would extend a bit on the backside of the VM and there you would have 2 rows of jacks.
The idea makes me want to try out if i could design it.

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#168

My concern isn’t if they can be touched, but if they can be used easily. Presently the pots only extend a little above the panel. Though the PCB could stand off by only a few mm, (maybe losing 5mm including the PCB) if you wanted to keep the jacks near the corresponding pots (as the pin patch points are). With a relatively large jacks (I mean the entire box), which is around 9mm tall, adjacent to a pot shaft that’s only extending a few mm above the PCB, I think it would be hard to use. Adding a knob cap or other “pot shaft extending techniques” may suffice but I’d be worried about practical usability once patched. I’d love to hear how it goes off you try it out though!

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#169

Oh wait! It’s already done!

123137023_10158215918086896_3574824874162550844_o
123137023_10158215918086896_3574824874162550844_o1975×946 359 KB

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#170

holy hell that looks amazing! where did you find this?

#171
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#172

This is absolutely incredible!

#173

Nice! I guess there is a second PCB that hosts the jacks that connects to the first via some headers? It’s a nice clean design anyway. It also avoids the problem I mentioned by putting the ports below the panel (at the expense of not keeping them near what they are controlling). You could also add a third PCB for level conversion (in eurorack) to allow full range modulations in and out. I had assumed that a eurorack conversion would pull the device out of the case and place it below a more compact panel, but this looks nice (I’m guessing 32HP?).

#174

Some findings on my first noodlings and hackings:
-it sounds pretty cool, expected much more annoying noises but can dial in sounds pretty fast.
-it has brass, flute, clarinete and sometimes piano esque vibes to me.
-hacking a bigger speaker on works fine, if you want to, VM wants to start up with it and doesnt really like testing cables to speaker while running (often stays quiet).
-hack points to put certain jacks to 3,5mm are very easy and logical acsessed from the bottom of the pcb. My main goal is getting out pre verb for external lpg and fx etc or simply adding a monitor mix in to the speaker. Not sure what makes more sense probably both
-oh i think i broke 2 cables right away…they really suckk concerning stability.

#175

Would taking the Ground off the midi spot at the pcb named GND to in/out 3,5mm jacks work for shared ground with external signals?

Having a bit of trouble understanding where to rip the signal to a jack with the option of killing the internal signal flow to the reverb so i dont end with doubled signal (while that could be interesting for adt). Not sure if chanceling lpg 1 out by plugging it into lpg 2 and also ripping at lpg 1 while feeding back after external fx to the verb in is the best method.

#176

There will be a huge number of places to access ground (it’s almost always the biggest net on the board); it’s only labelled there as one of the pins on a midi connector is known as “ground”. Typically you’d aim to take the ground from as close to the exit from the power section as possible (to potentially minimise noise, as there is usually the cleanest power there due to filtering) but any ground point on the board (including the midi one) should be acceptable: I’d expect them all to be electrically common. Other potentially easy points are the jacks (whose sleeves connects to ground). The board might even have ground available where it screws into the chassis (if they use plated through holes) connected to a ground fill. A multimeter set to check continuity should suffice to locate others one you’ve found one.

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#177

Sorry for another hijack will compensate with a nice shot when the modded instrument is finished, but i want to skip the faceplate DC connector.

-is it safe to use the battery cable to a DC plug?
-if my 9v source is center neg and i have a pol changer i should be save to change the VM connector to 2,1mm and simply wire 9v+ to hot and ground to neg/shield correct?

Asking bc i am not sure if the batteries get some kind of voltage conversion

#178

I can’t speak for this device in particular, but often the battery terminals pass through a boost circuit (DC to DC voltage conversion). This then passes to the same circuit as the DC input is routed (power filtering and voltage regulation). This is because batteries tend to run at lower voltage than the DC. Voltage regulators typically need some voltage headroom above their output on the input, so if you don’t boost the voltage of the batteries they will cut out while still providing more power than is required to run the device.

As an example, a working NiMH battery might output 1.2V: 6 batteries give 6x1.2 =7.2V; a set of fresh alkaline cells might provide 9V; the voltage at which either cell is “dead” is about 1V, which puts the output at around 6V (which is the lower voltage bound for most 5V regulators).

That all being said, the battery terminals probably never see 9V. The boost circuit is probably okay with this, but I’d recommend checking it out to confirm. Someone may already know this, but identifying the boost circuit and checking the data sheet would be possible. If you are unsure, another option is to send power to the DC points where the jack connects to the PCB (no need for the jack).

#179

Thanks thats why i asked, better to solder to the original dc pins then instead using the battery cable

#180

Just jumped into Volca Modular after a long time away- makes more sense after building a bigger modular. Thanks to tips here, I just figured out how to route Kastle’s audio through the two LPGs and reverb, gave both portables new life! Fun playing Kastle’s pattern generator against VM’s sequencer. Also the DuPont cables seem to work ok patching between them, leaving the Stereo cv input for more connections.

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