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Comment by glitchc | Hacker News Reader

While this is a cool idea, it's not terribly useful for anything more complex than a toy example. The fact that I need to physically wire the components and manually adjust coefficients every time I create a new program means that I can only really leave one complex program configured at a time. How do I switch between programs? Do I buy new THATs then?

It would be much more practical if the analog components could be configured digitally through a script, so that multiple programs could be constructed and run on the same compute platform. A hybrid platform of sorts.

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> The fact that I need to physically wire the components and manually adjust coefficients every time I create a new program means that I can only really leave one complex program configured at a time.

This is basically the reality of every musician making music with guitar pedals and modular synthesizers. And the answer is, yes, you physically make the thing you want. Once you're done with it, you tear it down to make the next thing. That's part of the magic.

It's like building something out of LEGOs. If you want to re-use the pieces, you need to take apart your creation.

Why can't it work like an FPGA? I set the coefficients in software, it programs the analog computer through a serial interface, and then I don't need to tweak knobs every time I want to change something.

It can do. Digital switching of analogue signal paths can absolutely be done. MAX335/336/337-type chips are one way of doing it, and they've been around for decades.

That could be done, yes.

Perhaps a more interesting question is to ponder why an artist might not want that flexibility. How does it affect their creative process when in order to make a new sound the old one must be destroyed? Are there positives to that workflow?

A permanent analog computer is just an analog circuit. You can build a PCB with op-amps after you've proved it out.

From a mainstream perspective, there are mixed mode ICs that contain a bunch of analog components (op amps, comparators, etc.) and allow you to configure them digitally. E.g. the whole PSoC series from Cypress (formerly, now Cypress is part of Siemens).

Slightly less mainstream, there is the concept of FPAA (field programmable analog array), which is the equivalent of an FPGA but for analog instead of digital.

E.g. see https://www.anadigm.com/fpaa.asp.

One of the features listed: "An interface for controlling THAT digitally to develop analog-digital hybrid programs"

You're describing a 'field-programmable analog array' (FPAA), the analog equivalent of an FPGA.

i’m not sure how to find the photos but on some old analog computers, the entire patch board is swappable. to run a program, you would choose from your physical library of patch-boards.

kind of like moving an AVR chip from one breadboard to another

so in your mind, are FPGAs also only useful for toy examples? also, how often do you think a pcb of an electrical product changes once deployed?

FPGAs are certainly far more useful due to the fact that you can design and simulate them digitally and then mass produce them from that design. You can work on as many FPGA designs as you want in parallel without having to physically set up and tear down each one in turn.

They also don't cost $350 a pop.

Might want to look into the Bespoke Synth.

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