Home | ER-101 | ER-102 | ER-301 | Wiki | Contact

Scissors ✂️ paper and glue

Has anybody seen the new FSS OSC2?

I’ve spent the day thinking about how to emulate the basic foundation of this new oscillator inside the the 301 and, have managed to “glue” DNA from two different wave shapes across the positive and negative sides of a pulse wave and at the output glued together a new wave shape like I ain’t never seen before.

Thing is though, I would really like the thoughts and input from experts here who might be interested in what Finlay is doing. Is this really that new an idea or am I just getting into something that is already a known quantity?

Would love to know more and consider your thoughts should you have an opinion.

Have you seen the bphwr?

https://www.thonk.co.uk/shop/cfm-bipolar-half-wave-rectifier/

Very affordable and very fun! Is it something along those lines?

What method are you using to split and recombine the waves? Are you rectifying two waves, inverting one, and mixing them back together. I’m intrigued and would like to see any progress you make.

No not familiar with this, will take a look through the link.

Place a pulse wave in a global chain. On channel one I did positive wave rectified mixing through a vca which was controlled by the positive side of the pulse and on channel 2 applied the opposite, negative mixing through a vca controlled by the negative side of the pulse wave.

Link channels 3&4 into a stereo pair and bring each rectified channel through a mixer, left and right. Bingo. Spilt tea down my trousers in surprise at achieving this, and yet the real fun starts when you Inter-link pitch and FQ between them. Produces some lovely sounds

Are you also using a pulse wave to switch between the waves?

The pulse wave in the global chain is what drives the two vca. One by the positive the other by the negative, both being combined at the stereo output

1 Like

From what I can tell the technique is called Frequency Shift Keying (FSK).

http://www.cg-products.de/module/xr22-vco-ft/

1 Like

I had some good success replicating some of the functionality. You can get some nice beating timbres. Got some stuff reminiscent of super metroid. Higher frequencies end up with significant aliasing, but that can give its own sounds. I am interested in using different control waveforms, I think a sine wave might smooth out some of the switching discontinuity and could make for an interesting sound.

One of the things I love most about the ER-301 is how it allows you to take concepts from other modules and implement them in new ways, like using a wavetable of cello sounds with this technique.

1 Like

Damn right, a great way to learn more about the 301 and sound design is to model a device, have a clear image of what i’m going for

There’s been one of those on MG for as long as I can remember!

Today I tried a different approach using one channel. Two mixers, one for positive the other for negative rectification. In the sub chain placed a 3 band unit for sine, saw and triangle waves. Now, I can mix any combination of wave forms. CPU running at 14%

2 Likes

I just had a go at this after watching (most of) the DivKid demo. I did two versions one with triangle “dna” one with sine, CPU about 6-7%, added to my github units…

3 Likes

Will take a look at your unit later to compare build and routing techniques, for the mixing and modulation i’ve Been using an ET Levit8, perhaps it’s time to consider a fader type alternative!

1 Like

As I hinted at, I don’t consider it “finished”, but it was fun and had me thinking about things in the 301 I never did before. Might add more when playing some more with it and reviewing the divkid video again.

What’s worse is I might just have to buy the actual recombination engine module :thinking:

2 Likes

Listening to Findlay talk about the stability of the cem 3340 chip makes me want to pick a few up and make some diy oscillators.

Yes, he is quite particular as to how that specific chip provided the stability that allowed moving from software to hardware. Are they hard to come by?

Something I saw on his website, as an endorsement, was that Jimi Tenor uses his equipment, which is a massive feather in the cap as far as I’m concerned.

You can get them from thonk for around £10. They are a little pricey because they are official Curtis chips and his family gets a chunk. You can get a clone for cheaper if you are more budget oriented. One great thing about this chip is that it needs fairly little additional circuitry. I know look mum no computer uses them for his oscillators. I think his design is available if you are looking for somewhere to start.

You know what you’re doing, I’m strictly 301 and even that is tenuous :weary:

I just keep chanting, “DIY is the cure for GAS” while spending the same or more on components than on a finished module. The knowledge gained is pretty useful though.

1 Like