Trend price : 50€
The Paula audio chip was implemented into the commodore 64, all-time best seller into 2 main versions: MOS 6581 and MOS 8580 (for updated c64 boards). Sid is considered like a true synthesizer.
Overview
C64 / VIC64 HOME COMPUTER the main panel features a brown keyboard (66 keys) but no numeric pad.
Terminal connectors:
- cartridge slot
- TV connector (HF-Modulator- analog)
- audio/video DIN connector
-
serial bus (generally for disk drive)
- cassette interface 12 pins
- user port
- joystick (x2) 9-pins Atari type.
Voice
is based on a 8 -bits MOS 6510 CPU (about 1 MHz) derived from previous 6502 also can be an optimized MOS 8500. Graphic interface is managed by a 16 colors VIC-II (video interface chip at 320x200 pixels) MOS 6559 for PAL system. TECH: all data and IC are based on my Assy rev.C PAL 1983.
Sid chip
the SID (Sound Interface Device) a 28-pin DIP capsule audio chip was projected in 1982 by Robert Yannes (who worked for the Ensoniq Mirage sampler) for the American 8-bits computer Commodore 64 then revamped model C128.
The SID chip is a mixture of digital and analogue technology with phase accumulated oscillators and analogue multimode NMOS filter. SID generates 3 channels or oscillators (5 shapes: triangle, saw, mixed, noise, pulse variable width) with variable parameters:
- ringmodulator
- pitch detune
- hardsynch
- transpose
- delay start
- PWM
(variable width).
Sid Revisions
the 6581 was used on first commodore 64 from 1982 to circa 1986 with 4 main revisions (called "R1" "R2" [...] new updated C64 used the 8580 technically compatible with softwares but they did sound different mainly for filter structure.
Filter
multimode resonant filter with cutoff range from 30 Hz to 12 kHz:
-
lowpass at 2 poles
-
bandpass at 1 pole
-
highpass at 2 poles
-
band reject at 1 pole
The Cmb64 can filter external sources using the audio/video DIN connector.
LFO
up to 4 bipolar delayed assignable modulators with fade-in, variable depth. The modulators are identical and features 7 shapes; in addition 2 LFO can be combined for more complex waveforms.
Envelope
4 EGs, 4 stages ADSR structure :
- EG1 OSC1 amp
- EG2 OSC2 amp
- EG3 OSC3 amp
- EG4 VCF filter.
Os
is basically composed by 3 EPROM:
- 901227-3 KERNAL
- 901226-01 BASIC
- 901225-1 Characters map.
Memory
64 Kb Ram (8 X soldered IC 4116).
Audio demo:
Video Clip:
Review
OK: -history-sound-cheap
NOT : - time reliability- obsolete
Sid is something incredible, a cheap but great synthesizer for the mass: the music will never play 2 times the same way!
Text , review, special demos copyright polynominal.com / Eric Pochesci