ALF Music synthesizer

Some more details:

ALF made two different cards, one was a 3-voice card, which produced only square waves, and used VCO (voltage controlled oscillator), the 74LS624 - which you can still get
from places like Mouser Electronics and Digikey. It apparently could generate tones over 8 octaves, but the AY-based cards could not.

The other ALF card was a 9-voice version, using the AY-3-8910 or AY-3-8913 chip (which was also used in the Mockingboard and AE Phasor cards).

I don't have schematics or a physical copy of either card, but the company NuScope Associates produced a "cloning guide" for what seems to be a replica of that card.

Some music made with the card can be found in these places:

above the garage

Henry Spragens (h3nry)

Here is a list of chips on the "clone card" page, which I assume are in the 3-voice ALF card.

1 - 74LS624 - voltage controlled oscillator
1 - 8253 (programmable timer - Intel support chip common in old IBM PCs)
1 - 74LS32 - Quad 2 Input OR Gate
1 - 74LS04 - Hex Inverter
2 - 74LS75 - 4 Bit Bi-Stable Latch
4 - CD4723B - Dual 4 Bit Addressable Latch
3 - 8227DP - Audio Amp? (can't get an exact match for this part #)
1 - LM307 - op-amp

Antony,

Thanks for the photo and documentation!

That appears to be the second generation "AM II" card, as it has three 4 76489 PSG (programmable sound generator) chips on the board. I've never seen that card in person, though.

I have seen disk images at http://eightbitsoundandfury.ld8.org/hardware.html#alf, but don't know what version of the card they are four.

The 76489 PSG (programmable sound generator) is similar to the AY-3-8910 chip used in the Mockingboard. It has 3 voices per chip, so 9 voices per card. The Original ALF card has

Here's what I understand about the differences (from an ALF ad announcing the AM II card)

ALF Products AMS (Apple Music Synthesizer - 1978)

• 3 voices per card
  
• 78db dynamic range
  
• 8 octave pitch accuracy (> 88 piano keys)

ALF Products AM II (1980)

• 9 voices per card
  
• 28db dynamic range, 16 volume levels
  
• 6 octave pitch accuracy
  

I assume that the first-generation "AMS" card actually used 74LS624 VCO (voltage controlled oscillator) chips to generate square waves, but it doesn't seem to use complex/programmable sound chips at all. Still trying to confirm that.