kpmancus@phoenix.PRINCETON.EDU (Keith P. Mancus) (07/17/87)
All this talk of ancient (:-) technology is great fun. I'm only 20 years old, so it sort of has an archaic flavor. My only encounter with a vibrator-type inverter was in an old aircraft radio that came with our 1946 Ercoupe. The radio was probably circa 1960-65, especially since I've seen ads for the identical model in aircraft magazines of that era. The inverter (which was a remote box weighing about 10 lbs) was the noisiest electronic gadget I've ever heard. Everything worked, though. Strangely, the tuner for the receiver was a variable capacitor rather than a rotary switch. Why did anybody want to be forced to fine-tune the silly thing? I've used magic-eye tubes too; our capacitance-tester uses one as an indicator. (Late 1960's technology.) And our first digital multimeter had a Nixie-tube display. Gee, things change quick! I can also remember when calculators not only used LED's, they used *28 separate LED's* to make one digit. The power requirements were pretty high for something battery-powered. (Whatever happened to rechargable calculators?) It isn't only the old fogies who remember some of the neat stuff. :-) Keith Mancus <kpmancus@phoenix.PRINCETON.EDU>
kpmancus@phoenix.PRINCETON.EDU (Keith P. Mancus) (07/17/87)
Whoops, forgot the part-hunt. Does anybody know of a good synthesizer-type chip with 2 or 3 voices and a mixer? Primary considerations are smallness and price; this is a personal project and my wallet is pretty empty just now. Keith Mancus <kpmancus@phoenix.PRINCETON.EDU>
larry@kitty.UUCP (Larry Lippman) (07/18/87)
In article <448@phoenix.PRINCETON.EDU>, kpmancus@phoenix.PRINCETON.EDU (Keith P. Mancus) writes: > Whoops, forgot the part-hunt. Does anybody know of a good synthesizer-type > chip with 2 or 3 voices and a mixer? Primary considerations are > smallness and price; this is a personal project and my wallet is pretty > empty just now. Try the TI SN76489A, or its equivalent by NCR - the 8489. The IC provides three tone generators, a noise generator, four programmable attenuators and a mixer. It's a nice IC for microprocessor control (for all intents and purposes it cannot be used on a standalone basis). I don't have a pricelist handy, but small quantity pricing should still be less than $ 5.00. <> Larry Lippman @ Recognition Research Corp., Clarence, New York <> UUCP: {allegra|ames|boulder|decvax|rocksanne|watmath}!sunybcs!kitty!larry <> VOICE: 716/688-1231 {hplabs|ihnp4|mtune|seismo|utzoo}!/ <> FAX: 716/741-9635 {G1,G2,G3 modes} "Have you hugged your cat today?"
sbishop@watmath.UUCP (07/19/87)
In article <448@phoenix> kpmancus@phoenix.UUCP (Keith P. Mancus) writes: > Whoops, forgot the part-hunt. Does anybody know of a good synthesizer-type >chip with 2 or 3 voices and a mixer? Primary considerations are There is a chip that was (is?) made my TI, part number SN76477N. This device has a low frequency osc, vco, noise generator, and full envelope generator, and a three channel mixer as well as a variety of external inputs and controls on a single 28-pin DIP. The timing and frequency characteristics are controled by placing appropriate caps and resistors on the pins. The SN76488N has an internal amp which will drive an 8ohm speaker, the 77N has a low level output. Power is 4.5 to 12 volts (9 works best). If you use a bunch of these chips, you'll get the required number of voices. Brett L Maraldo