What do you mean, a clone of Akai's S56usb USB card?
As often happens, it's a long story that began in the early 2000s with the purchase of an AKAI S5000.
The machine seemed very interesting to me and had the advantage of being remotely controllable by a windows PC. Well, as a remote control, it's really just a replication of the machine's control panel on your PC. A sort of front panel – not hardware-based like on the S6000, but software-based. This was on Windows XP. Obviously, Akai never updated their software, which was called Aksys I believe, and they had no reason to, since the machine hasn't been available since 2002. Too bad.
In fact, I 'believe' Aksys could also directly control some features and edit the S5000's samples. Still, considering just the 'remote control' functionality, it was already excellent.
However, a few years ago, a French compatriot developed the equivalent of the Aksys software for Windows 10 & 11.
He also set up a Discord account dedicated to the development of his software : http://s56sys.free.fr/index.html. While browsing his Discord, I realized that there were people interested in his application, but that unfortunately, not all S5000 owners had acquired the USB card enabling communication with the PC. This card having become rare, it can be found, but at a fairly steep price – typically between $140 and $180, according to my Internet research.
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| S56usb Akai card. |
Beyond the price, the real problem is the availability of this USB card. A little nudged by the software developer, who was able to give me some information on the various signals on the card's S5000 connector, I ended up taking on the challenge of reverse-engineering this card.
Knowing that I had the pinout for the S5000 bus connector – which was supposedly valid – and that I also had an original card, I figured it shouldn't be too difficult to determine the entire wiring of the card, given that it's a double-sided board with no internal copper layers.
However, the card has an address-decoding PAL that doesn't just decode addresses. I've always had my doubts about the role of that PAL.
Be that as it may, I went ahead with reverse-engineering the card. As expected, it didn't take me long to draw up the schematic in KiCad – a few hours, and then a few more hours of verification. Which didn't stop me from making a glaring mistake. But hey...
With that done, I still had to figure out the equations governing the PAL. This component doesn't just handle address decoding and other read/write signals to and from the S5000 – it also generates two timing signals based on a simple RC cell. I don't know exactly what these two signals are for, but I imagine they advance a state machine. In any case, I went with that assumption and took on the PAL with a 'brute force' approach using a Pi Pico.
The Pi Pico I had was the version 1, with the pull-up issues. I had to tinker a bit to get a working setup. Once that was done, I cycled through all the binary possibilities on the input pins, sending the output pin readings via serial link to my PC for analysis. From that point on, it wasn't difficult to recover the logic equations.
Except, of course, for the two input signals coming from the two RC cells. Because, in fact, I had to look at all the outputs potentially affected by these two signals, as well as the other incoming signals involved in this setup, to choose the right configuration. Actually, I went at it by dichotomy. Between that or wasting tons of time with the logic analyzer, I tried the first option. A GAL makes that kind of thing easy to play around with.
Anyway, after a certain amount of time, the card finally ended up being recognized by the S5000 and the PC.
So I was able to test the communication with my PC running Windows 11 and confirm that practically everything works. The only issue at the moment concerns file transfer from the sampler to the PC. It doesn't work and triggers a USB time-out error on the S5000. Since transfer from the PC to the S5000 works fine, and having observed the same behavior with the original USB card, I concluded that it's a software issue on the PC side, not a problem with my USB card.
So I reported it to the software developer on Discord. He's given me an appointment in a few weeks' time, to give him time to fix the bug. Because it seems to me that when I shared my findings with him, he had a pretty good idea of where it might be coming from. So I'm hopeful that he'll sort it out. Especially since he plans to add sample editing functions, which would undeniably be a plus, bringing the application closer to Akai's original one.
I do enjoy interesting and productive ways to get back to business...
