ReSeed – SID music for the Commodore 16 and Plus/4

This external expansion device allows Plus/4 enthusiasts to experience the iconic three-channel synthesizer sound of the Commodore 64 while preserving the authentic retro experience.

Sounds from the C64 now for the Plus/4! Just plug the card into the Expansion Port! You can adjust the volume on the card. You can hear the sound over the Plus/4 audio or take it over a 3.5mm-Stereo-Cinch to a mixer or HiFi-Device. A 9-pin D-SUB connector allows connecting a 3^rd (analog!) joystick or a proportional-mouse or (why not?) paddles! (Source)

Background and Significance

Released in 1984 by Commodore Business Machines, the Commodore Plus/4 was built around the TED (Text EDitor) chip, which handled both graphics and sound. While the TED chip offered advancements in graphics (e.g., 121 colors) compared to the Commodore 64’s VIC-II chip, its audio capabilities were notably limited. The Plus/4 provided only two-channel sound without envelope control or modulation, falling short of the rich, three-channel synthesizer sound of the C64’s SID chip. This limitation contributed to the Plus/4’s modest market success, particularly in gaming and demo scene applications.

The Reseed sound card addresses this shortfall, enabling the Plus/4 to achieve SID-like audio quality, breathing new life into this classic 8-bit computer.

The Synergy SID Card, developed by Christian Schäffner (known as Solder) in the late 1990s, was one of the first solutions to bring SID chip functionality to the Plus/4, allowing it to emulate the C64’s audio capabilities. The ReSeed SID Card, a more recent development based on Solder’s design, builds upon the Synergy SID Card with modern enhancements, such as reduced noise and improved compatibility. Both cards connect via the Plus/4’s expansion port, enabling the use of a real SID chip (6581 or 8580) or compatible replacements, transforming the Plus/4 into a platform capable of delivering C64-quality audio for games, demos, and music composition.

The ReSeed SID Card project is primarily credited to SukkoPera, a prominent figure in the retro computing community known for developing open-source hardware projects for Commodore systems.

ReSeed is derived from Solder’s SIDcard, with a few enhancements.

Features of the Reseed Sound Card

The Reseed is an external expansion device designed specifically for the Commodore Plus/4, offering the following key features:

• SID-Compatible Sound:
  • The Reseed emulates or replicates the sound of the MOS 6581/8580 SID chip at a hardware level, providing three independent audio channels with support for waveform generation (square, triangle, sawtooth, and noise).
  • It supports SID-specific features such as filters, ADSR (Attack, Decay, Sustain, Release) envelopes, and modulation effects, enabling complex, professional-grade music and sound effects.
  • The sound card delivers the distinctive analog-like sound of the SID chip, a hallmark of 1980s computer music and games.

• External Connection and Easy Installation:
  • The Reseed connects via the Plus/4’s expansion port (typically the cartridge port), requiring no internal modifications and preserving the computer’s original condition.
  • Its compact design aligns with the retro aesthetics of the Plus/4 while utilizing modern manufacturing techniques for reliability and ease of use.

• Software Compatibility:
  • The Reseed is compatible with SID-based music editors and games originally developed for the Commodore 64, allowing the Plus/4 to play C64 demo and game audio.
  • Dedicated drivers and software facilitate integration, enabling programmers to leverage SID-like audio in new developments or retro projects.

• Modern Technology with Retro Spirit:
  • The Reseed employs modern components to reduce power consumption and enhance long-term reliability while maintaining the authentic SID sound.
  • Additional features, such as stereo output or advanced filtering options, may be included to further enrich the audio experience.

Technical Specifications

While exact specifications may vary depending on the developer, typical features of the Reseed include:

• Audio Channels: Three independent channels with waveform generation (square, triangle, sawtooth, noise).
• Filters: Analog or digital filters mimicking the SID 6581/8580 characteristics.
• Output: Mono or stereo audio output via 3.5mm jack or RCA connectors.
• Connection: Interfaces with the Commodore Plus/4 expansion port (typically the cartridge port).
• Power Supply: Powered externally or via the computer’s power supply, with low power consumption.
• Compatibility: Fully compatible with Plus/4, C16, and C116 models; partially compatible with C64 software (audio aspects).

Benefits and Applications

• For Gamers: The Reseed enhances the gaming experience on the Plus/4 by delivering C64-quality audio, particularly for titles optimized for the SID chip, making games more immersive.
• For Demo Scene and Music Creation: The Reseed opens new possibilities for the demo scene and retro music composers, allowing the Plus/4 to run SID-based music while leveraging the TED chip’s graphical strengths (e.g., 121 colors).
• For Nostalgia and Modern Use: The Reseed is ideal for enthusiasts seeking to relive the 1980s computing experience with modern reliability and superior sound quality.