Kara-Moon Forum

Developers & Technology => Hardware => Topic started by: folderol on September 25, 2007, 08:55:40 PM

Title: A trip down memory lane
Post by: folderol on September 25, 2007, 08:55:40 PM
Being somewhat a squirrel, I am loath to throw anything away, but sometimes the junk piles up so high it just has to go. My latest exploration of the attic unearthed the few remaining notes of a project I started in the middle 1970s.

Being fired up with the 'new' concept of digital audio, along with availability of relatively cheap logic chips (the famous 74 series). I decided I was going to design and build a totally digitally structured electronic organ.

I would have a master clock running at a 'colossal' 33,488kHz (2 * the highest audible even harmonic of C) and plugin cards of wavetables. There would be full ADSR shaping, some filters (didn't know much about them at that time) and a whole two LFOs.

I reckoned I could create at least 8 * 3dB step keyboard velocity sensing (at a time when there was little or none commercially)

Reverb, phasing and ring modulation could be relatively easily done digitally

Only at the final stage would there be a pair of 12bit DA converters to recover the analogue stereo signal.

It took me about 18 months to get enough design done for me to tentatively work out the build cost.

It came to about 500 uk pounds, at which point the project slammed into the buffers. That works out around 10-20k in todays prices.

Anyone want a set of 12th root of 2 tables (7 decimal place accuracy) ?