[sdiy] My new ESQ-1

[Tim Parkhurst]

> -----Original Message-----
> From: Rainer Buchty [mailto:rainer at buchty.net]
> Sent: Tuesday, May 31, 2005 1:57 AM
> To: Tim Parkhurst
> Cc: 'synth-diy at dropmix.xs4all.nl'
> Subject: Re: [sdiy] My new ESQ-1
> 
> Tim,
> 
> >Just scored an ESQ-1 for $50 at a used music equipment store! Its
> >only problem is that one ovtave of the keyboard is dead.
> 
> An octave or "just" a block of 8 keys? If it's nothing more or less
> mechanical, i.e. the keyboard itself, keyboard PCB, or diodes, the
> only remaining failure is the keyboard processor -- which seems to die
> quite often on the ESQ1.
> ***************
Actually, you're right - it is just a "block" of eight keys that are dead.
Here's the funny thing: while poking around with the sequencer, that block
began working again, but only once. As soon as I tried to play those keys
again, they wouldn't work. Also, it seems like I can sometimes get one or
two keys in that block to work, but they'll only behave through one
keypress. If I go back and try to hit the same key again, it doesn't work.
Change programs, jump through some of the menus, and sometimes a dead key
will work again, but for only one keypress. This is sounding more and more
like an intermittent connection or perhaps a semi-dead/confused keyboard
processor. It behaves flawlessly over MIDI, so luckily it is still very
useable. Looks like the MIDI implementation includes pressure response, even
though the ESQ's own keyboard doesn't put out pressure info. My M6 does
however, and that's what I'm using as the 'master.'

> >The MIDI in is just fine however, so the dead keyboard is not a
> >terribly big problem. You know the sad thing? Looks to me like this
> >unit STILL has the factory patches in it!
> 
> What OS version does it run? (Hold down REC and press MASTER.) The
> latest is OS3.5 which also contains factory presets, any prior OS
> requires you to load factory presets from tape or via MIDI.
> *****************
The keyboard version shows the OS on the main display when I first fire it
up (although your excellent keypad shortcuts work also). It is running v2.3.
I definitely would like to get the latest OS burned into some ROMs (don't
have the equipment myself).

> >Anyway, it makes some great electronic / ambient sounds (not so hot
> >at imitative, despite the fact that the factory sounds try to 
> >emphasize this).
> >If anyone has links for good ESQ-1 info / mods / schemos or sounds,
> >I'd appreciate it.
> 
> Shameless self-advertising follows:
> 	http://www.buchty.net/ensoniq
> 
> Also includes customization for your ESQ1 OS such as including own
> "factory" presets, changing default settings etc.
> ******************
Found your site and bookmarked all the ESQ related pages. Excellent stuff! 


> >Also, I'm thinking that the ESQ's voice architecture might be worth
> >studying/replicating with a couple of AVRs. A one-voice ESQ would be
> >a nifty (and realizable) micro-based project. Or so I think. :)
> 
> See http://www.buchty.net/ensoniq/files/ics1261.pdf for sound chip
> details.
> 
> Each oscillator is basically a 24-bit phase accu with 16-bit
> incrementum plus some bit-shifting / bit-stencil circuitry for proper
> wave address selection. I doubt, that a single AVR is able to supply
> more than the 3 required oscillators per voice with the required
> ~38kHz (8MHz/(8*(24+2))) update rate per osc.
> 
> Rainer
> **************
True, I think a single AVR might be straining to achieve a full ESQ voice,
but I was thinking more along the lines of having one AVR do the DCO / DCAs,
another AVR could handle the LFOs and EGs, and feed the whole mess into a
Curtis 3372 (VCF, final VCA) or something like that. I just thought the
voice architecture was very nice. Complex, and very tweakable, but not quite
as complex as the Oberheim Matrix series (therefore, easier to implement).
But besides all that, I found your ESQ pages to be a great help. Thanks
Rainer!



Tim (straining to achieve one full voice) Servo

"Imagination is more important than knowledge." - Albert Einstein





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