Akai AX-60 Custom Firmware (Akai AX60)

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Rasputin
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Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Tue Jan 31, 2017 7:18 pm

Since the AX60 has been a popular topic of discussion lately, and ideas of a new OS firmware for it have been mentioned, I thought I'd divulge that I've tinkered with the idea already. I've disassembled the ROM and broken it into data tables and opcodes as well as identified and documented key portions of it.

Yay! New firmware, right?

Well, no. At least not in the near future. I don't even have an AX60 to develop with, so it'd be impossible to test any changes even if I had made improvements to the firmware -- which I haven't. My only point in revealing any of this is that I have started the groundwork for such a project and have previous experience with this architecture, so I might be able to guide someone looking to tackle such a project or at least save them from having to reinvent the wheel.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by themilford » Fri Feb 03, 2017 3:39 pm

I'm am in full support of this. There are a few quirks that would need to be dealt with straight away... such as the arp stopping when patches are changed, or the jumping pots when trying to make small adjustments. There are a few key features I would like to see: Dual mode (ala AX73), double/layered patch mode (3 over 3), Midi-sync for arp. And obviously CC panel control.

I have mentioned elsewhere, I think crowd-funding to get you a working AX-60 (and possibly also an S612 to improve how they work together) and some income or compensation, would be the best approach. I would donate a few hundred to the cause, as I imagine many other would.

This is a worthy project.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Fri Feb 03, 2017 9:34 pm

If anyone has the AX73 or VX90 firmware (or any other brothers, sisters, cousins of that same Akai era) then I'd be interested in taking a look at those as well.

The AX60 firmware I have access to is the latest 1.2 revision, but I'd welcome any previous versions -- just for the sake of comparison.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by themilford » Mon Feb 06, 2017 3:24 pm

Rasputin wrote:If anyone has the AX73 or VX90 firmware (or any other brothers, sisters, cousins of that same Akai era) then I'd be interested in taking a look at those as well.

The AX60 firmware I have access to is the latest 1.2 revision, but I'd welcome any previous versions -- just for the sake of comparison.
I just ordered the 1.2 version for my AX-60... I have an eprom of the v1.1... happy to send that if you can extract.

One point of interest... So, the arpeggiator on the AX-60 does not output via midi, HOWEVER, when using the midi out to the S612 sampler is DOES arpeggiate the sampler. So there is some sort of midi arp output message that only the S612 reads and not a regular midi device... weird.

should we set up a crowd-funding page to get this project started? I'm ready to do all the marketing and press. ;-)
Last edited by themilford on Mon Feb 06, 2017 10:54 pm, edited 1 time in total.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Mon Feb 06, 2017 7:40 pm

themilford wrote:I just ordered the 1.2 version for my AX-60... I have an eprom of the v1.1... happy to send that if you can extract.

One point of interest... So, the arpeggiator on the AX-60 does not output via midi, HOWEVER, when using the midi out to the S612 sampler is DOES arpeggiate the sampler. So there is some sort of midi arp output message that only the S612 reads and not a regular midi device... weird.

should we set up a crow-funding page to get this project started? I'm ready to do all the marketing and press. ;-)
Yes, I can read a physical EPROM if you're willing to post it to me. Probably won't be TONS of help, but for the cost of $0.75 or whatever it takes to mail it, I'd welcome the effort. It's impossible to have too many sources of info with a project like this.

If the arp signal is generated then it should be pretty easy to pass that along to the MIDI output in a more proper fashion. The problem is that coding space is extremely limited. Any features are going to be limited to the highest priority stuff that can actually be fit within the barely available slack. MIDI CC might be doable because a fair chunk of code is already in place, but it's really hard to say until that bridge is crossed.

As a weird side note, the AX60 supports SysEx in a form. If you send a Tune Request then it will trigger oscillator autotune mode. Not an undocumented feature, really, but a covert one.

As far as crowd funding goes, the biggest problem is a productive outcome can't be promised, certainly not by me. I'm quite confident I can get SysEx patch save/load and MIDI CC working if I have the physical machine here, but it might require killing other less used features like tape dump or sampler support. I'm not that sure about any other feature, although I can't eliminate the possibility either. It's all hard to say--I have experience in this domain, but I'm far from magic.

I'm interested in achieving this, but it's a lot to ask both ways: for me to develop for a machine I don't own and have no personal stake in, and for other people to fund something that might not happen, especially since everyone probably wants a few different features. It would be a lot different if it was for an Ensoniq ESQ-1, etc. that you can find a junker project for $99 or so. An AX60 is going to be $400-450 minimum unless someone really lucks out with a guitarist selling it on Craigslist for $200 or the like.

I'm open to suggestions and/or discussion.

P.S. I think the MIDI arp, slider jumping, and arp cutoff issues are strong possibilities. SysEx save/load is likely, depending on space. MIDI CC is a maybe. Dual mode and the like... seems a lot more doubtful.
Last edited by Rasputin on Sat Jul 29, 2017 4:59 pm, edited 1 time in total.

themilford
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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by themilford » Mon Feb 06, 2017 11:14 pm

Thanks for your interest. Maybe it makes sense to just get a few very interested folks together to buy an AX60 and ship it to you. I would happily put $100-$200 into the project. Would you be happy getting an AX60 (and possibly an S612) for your efforts?

Keeping (and even improving) S612 capabilities is a must. I use the two in conjunction and plan to keep it that way. It's one of the strongest features of the AX60 IMHO.

I know in cases of other OS upgrades, Such as the KIWI JX3P or the Prophet 600 GliGli, there's more space added by adding a new more capable chip to run the OS. I have limited understanding of this... but check these out for reference, can we explore something like this?:
Image
Image

Also, as for value, there are many of these AX60s out there and more showing up all the time. They are still going for between the price of the JX3P and the P600 which both have seen a resurgence in the market due to the OS upgrades. It looks like those folks were able to commoditize the effort as well... which would be a plus for you or our little concern if were were to make a go at it.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Mon Feb 06, 2017 11:28 pm

themilford wrote:Thanks for your interest. Maybe it makes sense to just get a few very interested folks together to buy an AX60 and ship it to you. I would happily put $100-$200 into the project. Would you be happy getting an AX60 (and possibly an S612) for your efforts?

Keeping (and even improving) S612 capabilities is a must. I use the two in conjunction and plan to keep it that way. It's one of the strongest features of the AX60 IMHO.

I know in cases of other OS upgrades, Such as the KIWI JX3P or the Prophet 600 GliGli, there's more space added by adding a new more capable chip to run the OS.
It would be worth it to me, but as I said, (adequate) results couldn't be guaranteed.

A CPU replacement is beyond my skill level, but changing the EPROM to a larger chip is probably within the realm of possibility. It would require more than just a simple EPROM swap to get it to work though, I believe. Some soldering would be required as part of the mod, if that was the approach taken.

You should hit up Bob @ Tauntek and see if he has the inclination and time to do it. He's more than capable at delivering the goods. I'm but a pale imitation.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Sat Feb 11, 2017 5:01 am

I'm 95% sure I can now dump the mask ROM out of the CPU of the Akai AX60 if I have access to the hardware. Not that it really makes a huge bit of difference, but for the sake of academics, I thought I'd mention it's possible.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by countrushmore » Fri Feb 17, 2017 1:27 am

Okay so I don't know exactly what you are capable of doing with the firmware upgrade. But would it be possible to take the split mode and stack the split on top of eachother to make a dual oscillator 3 voice synth? This synth is by far my favorite and most versatile I've owned out of a jx3p, polysix, esq1, and moog rogue. I dream of building my own version of an akai ax60 with 2 oscillators.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Fri Feb 17, 2017 12:31 pm

countrushmore wrote:Okay so I don't know exactly what you are capable of doing with the firmware upgrade. But would it be possible to take the split mode and stack the split on top of eachother to make a dual oscillator 3 voice synth? This synth is by far my favorite and most versatile I've owned out of a jx3p, polysix, esq1, and moog rogue. I dream of building my own version of an akai ax60 with 2 oscillators.
Cool idea, but way out of the scope of anything I could deliver, space constraints aside. I'm not even sure how feasible the basic upgrade ideas are without hardware mods of some kind. I think the twitchy slider fix and more developed MIDI is about all that can be put into a drop-in firmware update.

It should be noted that this is something I'm only casually dabbling with when I've got copious amounts of spare time. Currently, I'm more-or-less just inspecting and documenting how the firmware works so that I can see what is likely achievable. If I had a real AX60 I could attempt to add a few basic features, but until then I'm simply lazily notating my discoveries for some future development (or ambitious developer) that may never come.

Specifically, at the moment I'm messing around with reversing the file format of the cassette tape output. I've got a pretty good idea how it is laid out, but not enough for someone to be able to make an editor yet, although I can encode/decode tape dumps from the AX80, AX60, AX73, etc. I know the format of the AX80 but not the rest of the family yet.

P.S. Is the twitchy slider thing something that happens on ALL machines ALWAYS?

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by countrushmore » Fri Feb 17, 2017 6:52 pm

my sliders are all little buggy sometimes but its hard to pinpoint when, I will take note next time I notice
SO IF MESSING WITH THE ROM TO DOUBLE UP IN SPLIT MODE WE WOULD MAYBE LOOSE AN ORIGINAL FUNCTION WITHOUT BEING ABLE TO CONTAIN MORE DATA?
WHAT DO I NEED DO WRITE MY OWN ROMs or whatever you call them?
this is from service manual
MODEL: AX60 No. MS-0008 DATE: March 1986
001 Subject: To improve performance
The ROM IC program has been changed to improve the following points.
1. AUTO TUNE request by MIDI is recognized but is not transmitted.
2. AUTO MUTE request by AUTO MUTE button is accepted up to 6 times causing
other functions inoperative for up to 30 - 35 seconds.
3. When VERIFY is executed and the data recorded on the tape and that of
AX60 is different whatever the reason may be, the data in AX60 may be
re-writen when PROTECT switch is off.
4. Since the position of PITCH BEND setting VR is memorized when the unit
is turned off, when the unit is turned on again after changing the
posistion of setting VR, the amount of Pitch Bend effect is different
from its VR position.
5. In SPLIT mode, the MIDI channels are set for Upper keys and Lower Keys
separately. But even after SPLIT mode is released, MIDI channels are
not caceled thus AX60 accepts 2 MIDI channels.
Ref. No. Part No. Description
(NEW) 3-IC7 EI-364674 IC TMM2764ADC AX60 VI.2
Changed from : January 1986
Service Ref. No. : CNL0101, CNL0113

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Sat Feb 18, 2017 12:00 am

countrushmore wrote:SO IF MESSING WITH THE ROM TO DOUBLE UP IN SPLIT MODE WE WOULD MAYBE LOOSE AN ORIGINAL FUNCTION WITHOUT BEING ABLE TO CONTAIN MORE DATA?
WHAT DO I NEED DO WRITE MY OWN ROMs or whatever you call them?
I'm not familiar enough with the voice architecture (yet) on the AX60 to tell you for sure if it's even possible to do what you propose, but if it was possible then yes, it would likely involve compromising some original function. Code space is definitely at a premium. Maybe I'll find some way to optimize something, but I don't see anything obvious.

If you mean you have a firmware lower than v1.2 and you want to update it yourself, you need three (relatively simple) things:

1) The update ROM binary. It's on the SkinnyV EPROM archive [http://dbwbp.com/index.php/9-misc/37-synth-eprom-dumps] or I have it. The archive has loads of firmware for all sorts of vintage audio gear (not just synths, but samplers and FX processors, guitar pedals, etc.) so it's worth visiting for future needs.

2) A 2764 type EPROM. These are inexpensive, only a few dollars.

3) A ROM burner that's compatible with your computer which supports 2764 EPROMs. A tad pricey, but a good investment if you maintain your own gear; for the price of a couple pre-burned ROMs you can instead own the equipment to churn out unlimited amounts of EPROMs for you, your friends, and other VSE members.

Alternatives are overpriced pre-burned ROMs from eBay (someone is selling this update currently, now that the ROM has been made public) or try JXAlex here on VSE for an EPROM for a very reasonable chip/burn/ship price.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rob Ocelot » Sat Mar 04, 2017 5:36 am

Rasputin, where are you located? If you are reasonably close to me I'm willing to lend you my AX-60 and S-612 for development purposes. I also have the ability to burn 2764 EPROMS if necessary. I used to have an EPROM emulator (Southern Cross) that would make testing code much easier than having to erase and burn an EPROM every time. I sold it to a friend years ago but I should be able to borrow it if necessary,

I'd rather not lose sampler functionality for the sake of CC control, but as a worst case scenario it wouldn't be terribly difficult to use a 27128 with two different firmwares (one written to higher addresses) and a switch to change banks. In this configuration the AX-60 will see each bank of the 27128 as a 2764.

Hopefully we can get one of the current synth upgrade developers interested in the AX-60. Kiwitechnics seems to have a lot on their plate. Covariance seems to have abandoned development of any new upgrades. Tubbutec seems like a good prospect, and I'm really impressed with his Polysix and Juno upgrades.


If anyone is interested, over on Gearslutz I've proposed and tested a mod to change the taper of the resonance pot to have better resolution for CV values below self-oscillation. Resonance still maxes out at +5V to get all those nice harsh sounds the AX-60 is known for but you'll have much more leeway for warmer, juicier tones. Instead of self-oscillation at 4/10 it's now happening at around 8 or 9/10. If you can solder it's a simple straightforward mod that doesn't involve a complicated swapping out the linear resonance slider for a log tapered one. It's also easy to make this behavior switchable (and potentially under software control in the future).

Another Gearslutter took this idea further and modded his ADSR sliders to have an antilog response to give more sense of change at lower levels (basically the opposite of the resonance pot response). I've done the same to mine and I feel this greatly improves the programmability of the synth.

Incidentally, you'll also be able to save and recall patches without problems with these two mods -- including patches saved before the mods were applied.

If anyone wants details I can post them here, or direct you to the thread on GS.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by themilford » Mon Mar 06, 2017 1:16 am

I would like those links Rob. Thanks.

I too would not want to sacrifice S612 features.

I'm also willing to let you borrow my AX60 and s612 if it turns out I am closer. My ax60 is in the shop but as soon as it is back, let us know.

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Re: Akai AX-60 Custom Firmware (Akai AX60)

Post by Rasputin » Thu Mar 16, 2017 2:11 pm

Sorry, guys, I haven't been actively watching this thread as I've been tinkering with a whole bunch of other stuff.

I'm tempted to at least make some firmware to dump the CPU mask ROM and have someone run it remotely. It would probably only take me a couple tries.

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