ES-5503 DOC - Dumb Newbie ALERT :)

[Ragnar]

Howdy,

Been a skulker for a while and have been following the MBSid and FM synths for a couple of months now (gotta get started on my own).  To call myself a newbie would be a real promotion - what's one rung below newbie-status?  ??? ;D

Now to my question (probably been asked by someone before - sorry if it has):  Has anyone arrived at any theories if the Ensoniq ES-5503 DOC sound chip is 'doable' within the MB design? What little of it I understand, I believe that it's a more complicated IC than the SID, so arriving at a design may be more trouble than it's worth.  Thought I'd ask anyway. ;)  Thanks for your time.

- Ragnar

[cheater]

Hey Ragnar,

read the FAQ first: http://www.avishowtech.com/midibox/wiki/index.php/HomePage

most notably: http://www.avishowtech.com/midibox/wiki/index.php/Question%20and%20Answers#QA104

(yes, I added it just now. :P)

Just wondering - did you find out about the FAQ after you asked your question (like I have)?

:)

[Ragnar]

Actually, I've browsed the FAQ a few times before I registered.  The FAQ's comments were circumstances that I had assumed anyway.  I didn't expect anyone to tell me how to do it, nor do for me.  I imagine that the occasionaly "how do I do this?" question regarding various synth ICs comes up a few times here, but that wasn't my intent.  When I re-read my post, I guess that's what it looked like, though.  I was just making an "any thoughts on this?" question/comment - entirely conceptual and theoretical. ;)

Found some sources on the chip and some data sheets.  If I were to get a few more years of serious electronic training/programming experience under my belt, I might give it a try.  I guess if I were to do some reverse engineering on some of the old Ensoniq synths that used this IC, I might arrive at something. :P  The Apple IIGS used it as well.

Thanks anyway.  ;D

[Duggle]

hi,

If you want people to comment on possibilities such as this,  then provide some background info that may be of use to others:

-Where do you get this chip?

-Why is it of interest?

-What documentation data sheets have been located (eg datasheets).

Some links.

I did a google search after reading the first post in this thread and found very few hits, with nothing at all informative, so thought the device was too obscure for anyone to be interested in.

(btw; I find the  WIKI QA103 a bit harsh, as I dont mind having various devices brought to my attention.)

cheers

[Ragnar]

Thanks, Duggle.  ;)

I had to do a lot of digging myself to get any info regarding this IC.  Found a German Ensoniq enthusiast that has quite a bit of info.  Here are a couple of links and a PDF:

Basic Data: http://www.buchty.net/ensoniq/5503.html

Pricing (these chips can be obtained as new/old-stock - they're not 'reclaimed'): http://www.buchty.net/ensoniq/shop.html

And a Data Sheet in PDF form: http://www.buchty.net/ensoniq/files/ics1261.pdf

I'm not even going to pretend that I understand everything that is being described.  It was capable of producing some rather neat sounds in the old Ensoniq synthesizers and gave the Apple IIgs an interesting slant in early computer music.  My curiosity came about when I saw the implimentation of the SID chip in the MBHP, so I started contemplating the possibilities of the old DOC chip in a similar application. ;)

Like I said earlier, I don't have the knowledge nor experience to work on this now (give me several years and I might...maybe...not?) but I thought I might throw it out there as something to think about.

Thanks again.

[cheater]

I'm sorry, my reply was a bit harsh indeed. Didn't mean to discourage you at all, I was too trigger happy. I guess SmashTV's harshness wore off on me a bit ;):P

32 oscillators in this chip? Interesting!

I wanted to experiment with something like that (load of oscillators) myself - though in analog

Make a very, extremely cheap design of an analog oscillator (don't care about the waveforms - cool if you could select at least tri/pw though), that is stable and low-noise. Each oscillator should have separate frequency adjustments. Wonder if it'd be easy (or more importantly: cheap) to make a switch for such an oscillator to turn it into an LFO?

Important part: use some 60 of those oscillators :D

Make a very crude envelope (maybe just AR), one for each of the oscillators.

Throw in 5 cool and complicated envelopes that you could apply to any of the oscillators separately.

Perhaps add one analog multimode filter assignable to each oscillator separately (switchable on/bypass for each osc)

Combine all that and you got one voice!

Cheap VCOs are crucial here.

Perhaps this could be realised with this chip? I wonder....

32 oscs/19 euro = 1.6 euro per oscillator. Not that bad!

[Ragnar]

No worries, Cheater.  ;)

If my memory serves me, Ensoniq used those 32 OSCs by doubling-down to 15 stereo OSCs and the remaining two OSCs for other processing.  They also had CEM analog filters in the chain in the old ESQ-generation instruments .

I think that before I try to apply this to a MB project, what I may do is get a hold of an ESQ-1 or Mirage on eBay and see what the architecture can do (at least how Ensoniq applied it).  Easier and less expensive to get an old Ensoniq than an Apple IIgs for experimentation ($500 US for a beat-up IIgs...I shudder).  What's interesting is that Big-E never published data on this chip, but Apple did for developers.  Another name for this IC that I came across is "Q-Chip".

[AndrewMartens]

I've previously looked at the possiblity of using the 5503 DOC-chip in a custom synthesizer.  Supplies are somewhat limited, though they can be obtained here-and-there for about $15-50.

I'm sure that one could create a 5503 synth module interfaced in a similar manner to the SID (a serial shift register that feeds a parallel output for DATA and ADDRESS lines, with one or two additional chip select lines).  It would require a closer look at the datasheet and programming interface to determine how easy/complex this would be, but should definitely be possible.  You really shouldn't need any reverse engineering to use the chip - just what's provided in the datasheet should be fine.  As a starting point, check out the MBHP_SID schematic to see how TK interfaced the SID, and then the MOS6581 datasheet to look at the control registers.  Then compare with the 5503.

IIRC the 5503 has a 16-bit address bus multiplexed with the 8-bit databus, which may need to be buffered from the input coming from the MBHP_CORE module.  I really like that you can load up your own wavetable into memory - that's a pretty cool feature, kinda reminds me of the wave-synth I have on my todo list.  The fact that you have to interface up to 128kB of RAM is a bit of a pain, but not impossible - it just makes the design more complex.

The 5503 is on my  "cool old digital synth chips to play around with one day" list, but that probably means that I won't actually have time to even think about making a design with it for several years.  That reminds me, I should probably buy one or two so that I actually _can_ build something with it when I get around to it...

Regarding the $500 US for a beat-up IIgs, that's way off the mark.  Check out  http://www.vintagefunworld.com/items.asp?ID=1 - I bought a SID, two Atari POKEY ICs, an AY-3-8914 and a YM2149F IC off the guy and he was a pleasure to deal with.  He has a bare IIGS for $30, or $40 with a keyboard, mouse, and power cable.  Buying an old Ensoniq would be instantly more usable, but you could probably get into programming the raw chip more easily with the Apple.

One datasheet for the 5503 is at http://www.buchty.net/ensoniq/files/ics1261.pdf - the chip also goes by the name ICS1261, along with 5503, DOC-chip, Q-Chip, etc.

[TK.]

This soundchip has so much registers, that they should be accessed with a parallel interface to reduce transfer time (see OPL3 module - the bus can be driven with the same pins like the LCD). You can use a 8-bit latch like the 74HC373 to multiplex the data and address bus. I'm not sure if the PIC is the right chip to control so much oscillators, maybe a 16bit chip is better due to the larger address range and faster processing of 16bit maths. Why not using an old Atari ST to drive the chip?

Best Regards, Thorsten.

[AndrewMartens]

TK:  parallel transfer is definitely a better idea - I hadn't realized that you had used a parallel interface to the OPL3.  A PIC may still be able to handle it - while the frequency registers on the 5503 are 16-bit, the volume registers are only 8-bit (which one would write to with the software-controlled envelopes).  Some of the 32 oscillators could be used as LFOs, thus taking that burden off of the PIC.

And besides, everyone loves using the PIC! ;-)  Hooray!

It's a cool project for someone ambitious, that's for sure!

[Ragnar]

Hey-hey  ;D

Good to see mondo-experts TK and AM weigh in on this.  I may pick up two or three of these ICs soon so that I have something to tinker with once I get back to college this fall.  Perhaps I should consider developing something from scratch rather than shoe-horn this into an MB setup (to oversimplify).  

About the pricing on the IIgs: I was being a bit facitious (sp?) in my analysis but the prices I've seen on eBay are still out of whack.  Thanks for posting the link to the old VG/CPU store.  Looks like a great source for this stuff.  Maybe the simplest thing for a guy like me who has less than no real experience engineering things from the ground up (electronically, that is) would be to do some programming directly on a IIgs, use a MIDI i/f (one was made for it, if I recall) and go from there with the intent to use the IIgs as an instrument.

Thanks for all of the input.  8)

[mythicbeast]

bump.... this would be aswome.