The SN-Voice Project: Finding Parts
The Never-Ending Search
Finding parts for projects is always a tedious process. Fortunately, some of the parts used in the SN-Voice can br procurred at some very interesting places, like Music From Outer Space or BGMicro - it's fun dropping by those sites, if only to press one's nose against the glass and pant.....
Obviously the most important part in the SN-Voice is the SN76477N IC. Though it has not been manufactured for years, it always seems to rise up in one surplus house or another. Even to this day, it's not a terribly hard IC to find.
The SN76477N is available in two flavors. There's the old "wide body" part, which has standard spacing between its pins, and there's the later "Shrink Dip" (SDIP) version, which requires some sort of adapter board if you expect to mount it on perfboard or protoboard - the pins are much more narrowely spaced, and these types of through-hole development boards will not accomodate the narrow bodied SN76477. If you've purchased the PCB, there is no need to worry about this - the PCB has pads that will accommodate either size of SN76477.
An excellent place to find the SN76477N is BGMicro. This is a fantastic place to get parts, and the people are really nice. Not only that, but they have the narrow body SN76477N for a very good price. They also stock the breakout board!
Arcade Chips offers both species of SN76477N - the old wide body, and the not quite as old narrow body or 'SDIP' package. The wide body is a bit more expensive than the narrow body, but, then again, the narrow chip pin spacing is not not on .01 intervals, such as the spacing is on most protoboards. If you're building on protoboard, buy the wide body SN76477N; that way you don't have to get a small adapter board to accomodate it.
Need a PCB? Check out sMs Audio Electronics' custom board.
Where To Get Your 2K Tempco.....?
Where else? Ray Wilson's fabulous Music From Outer Space!! While you're there, you might root around through Ray's stockpile of module designs and circuit boards - there's probably something there you could add to your SN-Voice, or add your SN-Voice to.....
You will find the 2K tempcos on Ray's catalog page, next to all the other cool stuff.....
Sadly, the LM394 is getting harder to find. Most reasonably matched NPN resistors will work, fortunately. THAT Corporation offers matched pairs in quad packages, and with a little ingenuity, it would be possible to use them. Mouser stocks the parts. You might think about matching your own transistors to do the job.
The LF444 can be found within the confines of the awesome Jameco, one of my fave suppliers.
Mouser's a good place for pots, caps, resistors and all manner of good things.
Last, but certainly not least, Small Bear electronics can fix you up with some really cool parts. Whenever possible, use this wonderful resource. Steve Daniels is a great guy, and he's doing something wonderful for the electronic music community.