MATRIXSYNTH: EXPERIMENTAL SYNTHESIZER BASED ON AY-3-8910 CHIP


Sunday, October 19, 2014

EXPERIMENTAL SYNTHESIZER BASED ON AY-3-8910 CHIP

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via this auction

"This auction is for an experimental synthesizer based on the General Instruments AY-3-8910 Programmable Sound Generator chip. The AY-3-8910 chip was used extensively in the early to mid 1980's as the main sound generator on a large number of commercial coin-operated video games. This chip has remained elusive to most since the extended data sheet is hard to come by. The chip was first manufactured by General Instruments from the late 1970's until the late 1980's, then a few were made by Microchip Technology. Early in the 1990's a pin-for-pin and functionally identical version was manufactured by Yamaha and sold under the part number YM2149F.

This experimental unit breaks out each and every register used on the AY-3-8910 into switches and controls so the user can manually adjust each of the three tone generators and the envelope control by means of control panel knobs. In addition, the unit is pre-programmed to work via a 61-key keyboard through the Lupine Systems Series 400 Keyboard Interface Board (included but not pictured). This interface board allows the user to connect any single pole un-matrixed keyboard to the unit. The programming is set up to assimilate each keystroke into the appropriate musical note assigned to each key. The user may shift the octave up and down by 1 on each of the three generators. The user may also select from the pre-programmed musical scale tuning or variable off-key tuning or a fixed frequency note.

Full envelope control is provided through the AY-3-8910 envelope generator. Included with the unit and pre-wired is one Lupine Systems Series 400 Filter/Modulator which provides basic LPF function and a LFO for modulation control.

The unit also has full control over the way the keyboard is scanned and processed, including an arpeggiator and key repeat/scan direction control. The speed in which the keys repeat along with the pulse width of the trigger can be adjusted to create a variety of unique sounds.

The unit outputs sound via four RCA jacks, one for each AY-3-8910 audio channel (A, B, C) and one "composite" output, which is an even mix of A+B+C. The unit also outputs a TTL compatable trigger for external triggering functions.

An expansion interface is also included which originally was used for a MIDI interface and to operate a YM2413 based voice unit.

Included with this auction is the entire experimental unit, one Lupine Systems Series 400 Interface Module for Parallel (unmatrixed) Keyboards, one 26-pin ribbon cable (which connects the unit to the Interface board), and a set of schematics. The schematics are for the Lupine Systems Series 400 Mini, which is very very very close to this unit but some of the pin numbers for the connectors may not be the exact same. A copy of the software for the PIC16F73 microcontroller is also included on CD-ROM in MPASM (assembly) format so you can see how the processor does its thing.

Keyboard is NOT included with this auction! Any 61-key keyboard (or fewer keys say 48 key is common on old organs) will work as long as it is NOT matrixed (multiplexed) and has individual switches for each key with a common ground bus."

I created a new General Instruments label for these moving forward. There was one post featuring the AY-3-8910 from Little-Scale back in 2011 here.


1 comment:

  1. Instead of auctioning off why dont you teach others how to build this fantastic device

    ReplyDelete

To reduce spam, comments for posts older than one week are not displayed until approved, usually same day. Do not insult people. For items for sale, do not ask if it is still available. Check the auction link and search for the item. Auctions are from various sellers and expire over time. Posts remain for the pics and historical purposes. This site is meant to be a daily snapshot of some of what was out there in the world of synths.

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