Blippoo Box by Rob Hordijk

So true.

In systems analysis and design a system is basically a collection of components that interact (work together) to achieve some goal. Just like in modular synthesis…

Breaking stuff down into their smallest functional components and figuring out how these components interact to achieve some goal helps you to understand how and why stuff works. And this can subsequently spark new ideas and enable the actual realization/implementation of ideas.

Also…can give you a healthy respect for the pioneers who came up with ideas and/or implemtations first.


@officialdjglitch - I tested the Palm Loop VCO in my Benjolin patch and it worked great. There was no need to use both V/Oct and FM inputs. Just as with the Pony VCO, I have the +/-10V main freq knob + attenuated CV + attenuated rungler all going to a mixer that attenuates the mix to 92% so as not to be 1V/Oct. That mix then goes to the Palm Loop V/Oct input. With the Octave set to 1, Course to -1.5 steps, and the Fine to -0.12012, I am able to get the same frequency range I was getting with the Pony. (I don’t remember the numbers, but it is close to the original Benjolin spec)

I also checked it and it works wonderful, Thanks for the tip! It makes the patch a bit more transparant on the oscillator part. Agree with @DaveVenom that you don’t need the double exp fm for the range, but you can make it really slow now which is also very nice and useful. Thanks again.

I will share my updated patch probably this weekend when I make some time for it

1 Like

That Blippoo Box emulation is a gem. Sounds great and is fun to play with. I also tried various other filters, but non match the Vult Unstabile (Free). Deep round low end and crisp high end.

I might try some more filters including the suggested Squinky Stairway.

Here’s Hainbach talking about and demonstrating the Ciat Lonbarde Benjolin/Peterlin. Also talking about Rob Hordijk (whom he knew and met) and the Benjolin/Blippoo Box. Also some talk and demo by Richard Scott of some specific versions of the Benjolin built by Rob Hordijk himself.

HAINBACH - Exploring The Ciat-Lonbarde Benjolin (now Peterlin)

Thanks! I have been pretty thrilled with the results of both the Benjolin and Blippoo Box emulations. And yes, that Unstabile filter is a beast in these patches.

Generally I get more excited over the Benjolin sounds than than the Blippoo Box. I feel I work a little harder to get self generated movement on the Benjolin, but I am more satisfied and intrigued with the results. Then again, I have spent much more time on the Benjolin emulation than the Blippoo Box.

I did have an opportunity to compare my Benjolin with a real After Later Audio hardware Benjolin, and the emulation held up amazingly well. We were able to dial in very similar sounds across both.

Seriously…Blippoo…Very fun name…cartoon

Yes. I guess I’m gonna use the Vult Unstabile more often as a sort of Resonator.

One of the more unique things with Unstabile is that when fed an audio signal there’s a slight slew in pitch before it gets to a stabile state. This slew follows the overall amplitude of the incoming signal and definitely adds to its character. Especially in feedback loops and/or when output is used for modulation.

In the Vult Unstabile product documentation it states:

With Unstabile remade the model (…) introduced nonlinearities that can occur when the circuit is fed with low voltage.


When fiddling with possible alternative filters at high resonance, approaching self resonance, I also tried the Instruo I-047 (emulating the ARP2500 1047 filter).

The Instruo I-047 has an 18 dB/Oct slope and has a nice ‘ring’ to it, without going into self resonance. I used two in series (it has no BPF, so I use LPF and HPF in series). I added Instruo Tanh to introduce/control some amplitude dependent non-linearity. Also an envelope follower connected to inverted cutoff modulation, emulation the Unstabile cutoff slew (prominent at high resonance). That configuration can sound somewhat similar to Vult Unstabile.

Amazing how something as unique and quirky as the Benjolin and Blippoo box can actually be emulated in VCV Rack…

1 Like

I am using the cytomic CF100 filter now in my emulations. Not free, but amazing sounds and very, very pingable.

1 Like

Yes - I have been experimenting with the CF 100 filter in other patches with great success, and was wondering how it would sound in the Blippoo Box and Benjolin. Now after your recommendation I will definitely check it out. Thanks.

It has a very controllable resonance (if you stay under 7.5 it has a large range of almost oscillation) I use the lp4 out for the emulations and feeding back the lp2 into the exp fm, creates the right harmonic distortion as described by Rob Hordijk.

But agree with you and @kwurqx that the Vult filters are awesome too. I am curious what will come with the updated code of the Vult filters!

This module also recently got added to the library.

I did not try it yet, but it sure looks like a Benjolin inspired module

You are right! Reading the manual it appears to be heavily influenced by Rob Hordijk’s Benjolin. I played with it very briefly. It seems pretty cool. But I am disappointed the manual does not at least acknowledge Rob Hordijk or his Benjolin and Rungler designs.

1 Like

Yeah, mentioning that would improve its integrity. We could politely point this out to the developer?

Do you know how far it goes into audio rate? I guess not as much as with our emulations, but I will check!

crashes Rack on add, on Mac arm64 at least… Just filed an issue on his github

It looks more like a Serge SSG inspired module to me : Serge Modular - Smooth and Stepped Generator (SSG) – Patch Point

I was super happy to see this whole Serge inspired collection but I’ve had a lot of crashes…

I don’t see that at all. Core to the functionality of the Digital Chaotic System (DCS) are an 8 step shift register with XOR feedback, and a 3 bit digital to analog converter, both of which are core to the Benjolin. As far as I can tell, the Smooth Stepped Generator has neither.

The DCS also has two VCOs (slow LFO to audio rates), each with inherent triangle and square wave outputs. I believe the SSG can generate both square and triangle outputs, but I don’t think it has two free running VCOs with both outputs simultaneously. (I really don’t understand the SSG)

Both VCOs go over 16 kHz

This is one of an interesting series of plugins, recently introduced under the name Patchable Devices.

There’s a wild State Variable Filter too…with a Ping input…but pretty hard too tame Resonance…

Well, I don’t have an oversampled stand-alone S&H yet… But my new Venom v2.6 beta has a new Benjolin Oscillator that includes an oversampled Rungler - and it definitely makes a positive difference at high Rungler clock rates! The oscillator includes everything a Benjolin needs except for the resonant filter.


The newest Venom 2.6 beta now includes a Venom S&H with oversampling options!


Here is a link to my updated Blippoo Box using my oversampled Venom Poly Sample & Hold Analog Shift Register.