Boredbrain’s INTRFX Review – Connecting Eurorack and Guitar pedals

I have a burgeoning Eurorack setup, and also some cool and unusual guitar pedals that I’ve been using on various synths over the last year, and I was looking for something that would connect the two worlds together succinctly in the way that I wanted. Why not just connect them together directly? They run different output levels and impedance. While quite a few guitar pedals offer input impedance that allows you to play synths and other instruments directly into them, if you plugged Eurorack directly into any pedal, you would just get nasty brokedown distortion guaranteed. If that’s what you’re wanting from your pedals, then you’re welcome, and read no further.

After a bit of searching, I came across the INTRFX by Boredbrain music. It immediately grabbed my attention as something that A) Looked interesting B) Looked solidly built, and C) Would fit my workflow perfectly. I bought one sight unseen, and thankfully was proven correct in my thoughts.

Boredbrain’s INTRFX is a 3-channel send/return setup, with a step down/up transformer to convert the levels/impedance. It’s housed in a relatively small standalone box, that enables fuss-free linkage between Eurorack and guitar pedals, or guitar to Eurorack, or standalone synth to euro, and so on and so on. 6 1/4″ in/outs line the side of the box, 6 Euro in/outs sit on the top of the box, and a mix knob per channel, each with CV input to control the blend with your rack. There’s a switch per channel, enabling the send/return routing to be either euro out to 1/4″, or vice versa.

So you can either use guitar pedals to affect signal from the eurorack, or you can plug your guitar in, and use the eurorack synth as an effects unit. Super flexible!

Once setup, I found it extremely easy to use – once I’d understood the routing on the box. The INTRFX has that excellent handmade, solid build quality, and feels like you could throw it off the top of your roof and it would damage the pavement. So no worries on roadworthiness there. The connections are all solid too.

I liked that it was 3-channel. A lot of the other options out there were only mono, so you’d have to throw in two before you could stereo-ize. This box enables stereo plus another channel. Eurorack is on the steady road towards stereo, so INTRFX is future-proofed in that sense.

Another absolute must for me was CV control of the blend. This adds so much more creative potential to the use of guitar pedals as effects. If you want a reverb sitting on a sound, the INTRFX can do it. But if you want an effect that cuts in and out in time with your eurorack clock tempo – then you can add interest to a sound without it being ever-present or overbearing. Another creative tool that I found that I couldn’t see on other similar products was the ability to feedback signals by flipping the switch – so you could feed the guitar fx signal back on itself, creating wonderful howling soundscapes with little effort. On top of that, you can also use the in/out of the euro side as a simple VCA (you can never have too many VCA’s in my book!)

One of the things that I loved about INTRFX is that it’s a standalone box, and not a module. There are loads of modules (euro) that already do exactly what the INTRFX does. But I didn’t want to take up precious space in my already overstuffed rack. This is the only one I could find that was in a guitar pedal format. I could stick it on my pedalboard and leave it there. Aside from space-saving on the eurorack, it also gives me the flexibility to use on the road with my synths without having to take my eurorack with me. It doesn’t come with its own power supply, which is a little bit of a bummer, but any regular guitar power supply works, so I just added it to the power brick under my pedalboard.


Really that’s all there is to say about it. It does what it says on the tin, very well. It’s a utility, but a quality one. Several people had questions about the 1/4″ inputs being on every side of the box, and whether that was a problem in terms of space efficiency. I would say if you’re looking for a desktop unit, then you’ll have to be ready for cables coming out of every side. If it’s patched in nicely to a pedalboard, you won’t even notice.

If you’re looking for connections between your synth/guitar worlds, and you don’t want to take up more space in your eurorack, I don’t think there’s anything that could best the INTRFX.The cost is $220, and well worth the dough. For more info here

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