Lupine Systems First Vintage DIY Analog Synthesizer For Sale

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Here's an interesting bit of DIY synthesizer history. The only other post to mention Lupine Systems went up last October here. Below are the details from the auction including a link to an audio demo. Note there is a Lupine Systems website still online.

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Hello DIY synthesizer fans! Way back in the 1970's I designed a number of synthesizer systems. Many of them were basic but for the time they were quite impressive.

I used to build small devices while in school to impress my friends. I often gave away copies of the diagrams, many of which I have seen online in one form or another -- many are very simple in nature and have survived the many years. This design is a hybrid -- the keyboard is digitally scanned but the audio is generated by analog circuits. This combo allows for the use of a matrixed keyboard. The heart of the system is the M50240 Top Octave Generator chip for which the output is divided down to lower frequencies and blended to form the sound to be processed by the filters.

Up for auction is a copy of one of my original synthesizers. The original was built using pad-per-hole and point-to-point wiring. I decided a while back to draft a set of printed circuits for this design "just for the heck of it". Up for auction are the results.

The PC board had a few drafting errors which have been professionally corrected with jumpers (a corrected version is now available but not yet up for auction).

All controls are fully functional and since the photos were taken I have added knobs to all of the rotating controls. I have also added a 1/4" phone jack for the audio output mounted on the rear (not shown).

PLEASE NOTE: THE AUCTION IS FOR THE SYNTHESIZER PC BOARD SET, NOT THE KEYBOARD SHOWN. The keyboard IS HOWEVER INCLUDED. The keyboard is CHEAP and is not of high quality so it is being TOSSED IN WITH THE AUCTION to get you started. Note in the photos that one key has been replaced and does not truly match the rest but plays OK. IT IS HIGHLY RECOMMENDED YOU REPLACE THE KEYBOARD WITH A DECENT ONE rather than rely on this toss-in.

Schematics are included with this auction.

If you would like to hear some of the sounds this keyboard makes you can Click Here for a wav file of the sounds."

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EXPERIMENTAL SYNTHESIZER BASED ON AY-3-8910 CHIP

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"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.

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