[sdiy] Anyone ever build a sampler?

[mikko.a.helin at nokia.com]

Get an old PC with a i486 CPU and SB AWE32, SB 32 or AWE64 soundcard (AWE64
has it's own memory system, the older SB's can use old SIMM's). Strip off
everything you don't need. If you have to get rid of the noise of PSU fan do
something for it. Don't use display adapter and monitor, build a LCD panel
for it. 90% of work is writing software for it. On Creative FTP site there's
a developer package (DOS, I'm not 100% if it supports SF 2.0 or SF 2.1, in
that case if you want use all commercial SF2 files use Win98lite and make
the 98micro Windows setup which takes only 50 Mb of HD space) for writing
the software which actually loads the samples into sound card memory and
plays the notes, you have to write the MIDI i/o part and the user interface.
Maybe the Windows based system is easier to build after all (less coding is
needed) though then you have to use a real monitor. Maybe you could find a
second-hand small (<=10") LCD display (VGA) used with some cash machines,
text processors and banking systems.

Also all or the SB card have noisy DAC's (cheap Philips I2S TDA something
part) and these have the output routed through Creative mixer chips which is
even more noisy. You can use the I2S interface to connect your own DAC,
actually you can use the Philips chip also but build decent active I-to-V
converter for it - Creative used a resistor to convert the output current to
voltage - as well as better opamp  for buffering the output (for low
impedance output). There's also the S/PDIF output, but I would use that for
interfacing digital recorders and DAW's. 

If you don't want to use PC's then just interface the SB card or buy some
DSP developement kit like ADI Sharc kit
(http://products.analog.com/products/info.asp?product=21065-HARDWARE) and
put in some more RAM and interface it with MIDI etc.

-Mikko

> -----Original Message-----
> From: ext Glen [mailto:mclilith at ezwv.com]
> Sent: 20. October 2001 7:05
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Anyone ever build a sampler?
> 
> 
> Well, I've gotten a few direct responses to my question so 
> far, and a lot of
> tangential chat to go with it.  :)
> 
> I was hoping to hear a higher ratio of direct responses, but 
> I guess building
> gear like this is a bit alien to a lot of the people on this 
> list. I'll admit
> that it doesn't seem like a trivial task to me, but I'm still 
> interested in the
> notion. I know that I could buy a sampler (if I had the 
> money), but I'd like to
> see what I can do on my own. As much as anything else, I want 
> the experience of
> actually creating something myself. One of the reasons that a 
> sample-based
> instrument seems interesting to me, is that it seems to be a 
> fairly unusual
> personal project.
> 
> A couple people on this list mentioned building simple EPROM 
> based 8-bit sample
> playback modules. I consider this to be a good start, and it 
> is indeed a device
> that employs sampling technology to synthesize a musical 
> sound, so it is almost
> a sampler. It just doesn't record its own samples. I'll 
> probably aim for
> building something like this, to start out. I don't even mind 
> if my initial
> testing is done with my PC as a controller for my external 
> sample player.
> Eventually, I'll need some sort of embedded control for any 
> serious project,
> but that can come later. I'm still learning and exploring at 
> the moment.
> 
> A friend of mine gave me a broken Ensoniq Mirage, and I'm 
> fixing it up. After
> working with that unit awhile, I developed an itch to hack it 
> into something
> more than it is. Like anyone who has ever used a Mirage, I've 
> dreamed of
> expanding the memory and disk storage options, but no matter 
> what cool fantasy
> hack I thought of, I ended up reminding myself that the 
> Mirage is only a
> single-channel, 8-bit sampler. Do I really want to put a lot 
> of effort into
> making a "SuperMirage" when I would have to scrap nearly 
> everything about the
> unit to make it sound as nice as I'd like it to?
> 
> That's when I started wondering about making some original 
> sample-based
> hardware of my own. However, if I make my own gear, I'd 
> really like to graduate
> to 16 bit sound. Does anyone have any ideas or sources for 
> obtaining cheap
> 16-bit A-D or D-A convertors? Possibly chips taken from old 
> sound cards or
> broken CD players? Does anyone know a source for new parts that can be
> purchased in single-unit quantity, at reasonable prices?
> 
> 
> Later,
> Glen
>