Fenix IV devblog KEEP ROUTING

Published by Priscilla Haring-Kuipers on

After a number of demonstrations of our Fenix IV ‘Superbooth prototype’ we have been working hard to develop the Fenix IV further and are getting closer to our ‘golden prototype’. Which is the prototype that has everything we want fully functional and is optimized for production.

Redesigning the power distribution

We decided to raise the distribution voltage throughout the Fenix and only down convert closer to the modules – mostly per group of modules. This means a much more stable voltage everywhere, which removes noise.


We have been getting this module tuned and calibrated to be identical to the Fenix II phaser – working together with master builder Bert Vermeulen. In the Superbooth prototype it used way too much power and didn’t sound right. Also some values needed to be adjusted to the new voltage and some things needed to be converted to our use of modern components. In order to properly test all of this we made it into a separate module. We are happy now and Bert approves.

Looking good

We’ve done a lot of little fixes in the phaser, upgraded VCAs, and adapted the scope modules. All over the Fenix we’ve made tweaks to make it look more balanced. For example, we moved all the push-buttons-with-LEDs into the title header of the module it belongs to.

DSP modules: noisebox digital oscillator and delay line

The algorithm in our noisebox is now feature complete. In order to give you the controls we think you need to properly explore our algorithm, we’ve added another knob to this module. Now we are hunting for finetuning. We think this noisebox is going to be very useable.

Our digital oscillator has grown one extra algorithm, exploring the phase distortion technique as used in the first algorithm. We decided one extra knob was needed to allow more tweaking of the different algorithms. There are too many interesting parameters to play with for just two knobs. We hope three will do.

The delay line now has a normal feedback delay, a waveguide,  a chorus/flanger and a reverb. All of the good stuff. Adding these was the plan all along but we didn’t have time enough to get this working before Superbooth. We think we got it now. We’ve made it musical with 1V/Oct tracking and great stability with high resonances. We think you’ll love playing with this.

Mixer – work in progress

We are rebuilding our mixer. It wasn’t working properly in the Superbooth prototype (while it did work on earlier prototype slabs), a chip might have blown out – we are not sure. While we were looking at the mixer schematics we came up with a new design with modern components which should be better, faster, cheaper and repairable. To validate this in hardware we also made a separate mixer module. However, we haven’t had time to finish soldering this yet… Working on it.

Handrouting all the circuit boards

Now that we are certain about all the hardware, we can optimize the routing on the boards. At the moment humans are still a lot better at routing than autorouters (typical NP-hard problem) and Stijn has been improving the earlier routing on the boards for weeks now and is about halfway. Go, go, go Stijn!

Oscilloscope autorouted

Oscilloscope handrouted







Coming up

There is still more work to do to bring down the amount of different kinds of parts. This count now stands at 253 which is way too high for production. This number includes some doubles and naming issues, and mostly concerns capacitors and resistors of different values and tolerances. When routing is done we can check everything against part lists and start bringing this number down. We hope to order our ‘golden prototype’ board at the start of September. In the Superbooth prototype the main board exists out of five boards – these will probably be split further into seven boards instead. Receiving this from our Chinese pcb-factory will be followed by about two weeks of full-time soldering for Stijn. Which means that having a functional golden prototype for Dutch Modular Fest is going to be pushing it (but hey that’s what deadlines are for, right?).

O’ we are also busy with a new design for the multiband filter but this is not ready to be revealed ….


Do you want a Fenix IV? Check out Getting a Fenix IV (the waiting list is now at 104)


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