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Re: Looking for ALF AM ][ disks images

On Thursday, October 11, 2012 1:07:27 PM UTC-7, Antoine Vignau wrote:
> Phil,
> 
> Disks are still *wanted* but manuals can be found at:
> 
> http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Audio/ALF%20Apple%20Music%20II/
> 
> 
> 
> ...or...
> 
> 
> 
> http://mirrors.apple2.org.za/Apple%20II%20Documentation%20Project/Interface%20Cards/Audio/ALF%20Music%20Synthesizer/
> 
> 
> 
> Antoine

On that second link, in the Photos folder, the photos named "ALF Music II Owner's Manual - Page 1.jpg" and also the one named Page 2, are not anything to do with ALF.  The "Page 1" one, for example, says "Vista Music Machine"... Vista being a different company than ALF Products.

I don't think I have any disks, but I will check.  I know the guy who wrote the software (I wrote the manuals), I can ask him if he has anything.

To clear up the chips mentioned earlier in this thread, the Apple Music Synthesizer (aka Music Card MC16) was the first music card for the Apple II, and  a pretty big seller.  Texas Instruments cloned that entire card into a single IC, the SN76489, reducing the number of bits in the frequency control and the exponential volume control, and adding a white-noise source.  ALF's Apple Music II (aka Music Card MC1) used three of the TI chips, and was also a large seller, and was cloned and copied by several companies (often illegally).  This is why the MC16 sounds better than the MC1... because it has better tuning accuracy and better resolution on the envelopes (crucial to doing additive square-wave synthesis) and volume.

General Instruments tried to clone the TI part, producing the AY-3-8910, but they messed up the waveform.  A square wave at one volume might be at 2V for half the cycle and -2V for the other half, then a square wave at a lower volume might be a 1.8V for half and -1.8V for the other half.  General Instruments had the lower half of the square wave at the same voltage no matter what the volume was... only the upper half changed.  This resulting in annoying clicks at every volume change.  Which might not seem so bad, but the volume changes rapidly during each note to create the "envelope" of the note, so the result was horrible.

Phil