Spitballin': Eurorack case pedalboard

jubal81

jubal81

Well-known member
I've had this idea kicking around in my head for a couple years that just won't leave me alone, but I can't wrap my head around exactly how to get it right.
Seems to me that the right Eurorack case would be a perfect pedalboard platform for a DIYer. Instead of a full-on pedal for every build, you'd mount your PCBs to blank panels with quick-connectors for the power/signal routing.

A 12u panel is just right for a 125B-sized PCB, meaning an 84u would get you seven 125B effects in 17 inches. Two rows of that would be 14 effects. It also means never having to mess with patch cables. It'd also be very fast and easy to swap out effects, so for DIYers with LOTS of drives, for example, you can just about hot swap them whenever. Rearranging your board would be trivial.

One of the tricky bits is that I'd like to add a tube preamp, my two notes cab sim and a Class D power amp so it'd be a whole rig in a box. That gets us to the power situation. I'm stuck on figuring out how to power this thing so I just need one 3-prong cord coming out the back. Plus, there's potentially limited space inside. I'd need 9V and 18V for most pedals, 12V for the cab sim and maybe 24V for the Class D power amp. The current demand will be mighty.

Also want to add the PedalPCB intelligent relay switching for 14 effects built right in to some kind of "motherboard." This would mean I won't need bypass circuitry on every effect I build and if I have 4 dirt pedals, for example, I could go from one directly to another. Or one delay to another - or reverb, ETC.

Ideally, I'd also like to fit a 9" reverb tank in there. I'm thinking it's all coming down to how the power supply plays out and how much space it takes up.

Anyway, here's some pics so you guys kinda get the idea I'm going for. First is a case from a selling on Etsy. It's the 3Ux2 that would fit 14 125B-sized effects on two rows.

6u-walnut.jpg


And this is a concept mockup up by Behrenger a year or two ago. I'd of course need foot switches instead of 1/8" patch jacks.

behringer-pedals.jpg
 
That's a great looking setup. You could drop 2 pedals from either end for power and other options?
 
fig said:
This is more and more intriguing. Do you have an amp in mind?
Click to expand...
I built a Tube preamp pedal earlier this year that I've already been using to run into my Two Notes cab sim. A 60W board like you see on the store here at PedalPCB would probably be close to what I'd use for a power amp.

Maybe I could get away with just having one beefy 12V supply. That could power the Cab Sim, Preamp and Power amp directly. I could use DC/DC iso converter bricks for the pedal power supplies.
 
I've used those listed here. They are very clean between 15-20vdc. I've tried a few others that perform a bit better at 9-12vdc. I'll look up where I found them.
 
Here's a quick comparison;

This is a TPA3118 chip build. 1x60w. 12-24vdc (15vdc min. by my tests). It has pads for a momentary mute switch (as if) and is very sensitive. I think I've managed to destroy a half dozen of these, but they are the cheapest I tried @ 2 for $8.


1625309459653.png


I actually ended up using this next one, a TPA3116 build. 1x100w, 12-24vdc, though I run mine 9v from my Voodoo and it is quiet. Much larger heatsink, terminal blocks rather than pads, and a handy output trimmer (as if). These were $13 a piece.
1625308929750.png
I got this one because it was to be the model for my DIY power amp. It has an LM3886 chip (I bought a few of these badass TO-220 amp chips) and uses through-hole components. At 8Ω, it runs 50/38watts. It can run 15-32vdc. I think I have one of these left. They were the most expensive I tried at $25 a piece.


1625309764910.png

I've probably have at least one of each. You're more than welcome to use or destroy them for your project.
 
I've tried both the TPA3118 and TPA 3116 boards, with very good results. More recently, I built up an amp using a TDA7498e, and that thing is LOUD. I use these little power amps into an 8ohm 1x12 cabinet, and I push them with a modeler / multifx pedal. My two main ones are the Line 6 HX Stomp and the Strymon Iridium. The 3116 and the 7498e are both very gigable (for the places I would play - bars). I use the 3118 for rehearsals - definitely loud enough for a basement.

My latest is a pre-built stereo amp based upon the 7498e, intended for hifi use. I use just one channel for guitar as I don't play stereo. I found it on sale on Amazon for $40. I can't build them for that, so I bought it.
 
I posted this elsewhere on the forum, but I will repeat it here:

I have a couple of Lenovo laptop power supplies that I would like to modify to use with these amp projects. I mainly want to cut off the plug, and solder on a more common 2.1mm x 5.5mm plug oriented the right way.

These power supplies have a ferrite bead very close to the existing plug. Is it needed in this application? If I leave the bead in place, I will have VERY little room for error when putting the new plug on. I might not even have enough space for the plug jacket. Can I cut off the bead and then solder on my plug or will that basically ruin the power supply for my intended use?
 
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