“CASIO RZ-1 Digital Sampling Rhythm Composer”

A demo video is available on YouTube — please check it out.

Condition:

• Serviced on June 18, 2026 — fully functional and working perfectly.

• Upgraded with custom EPROM firmware OS v2.0u. A DIP-28 IC socket has been installed, allowing future EPROM upgrades or replacements without any soldering.

One of the reasons the RZ-1 remains highly sought after today is its distinctive 8-bit / 20kHz sampling engine. The low sample rate and 8-bit resolution produce a gritty, crunchy character that is difficult to replicate with modern samplers. It excels at adding unique lo-fi coloration, vintage digital texture, and raw character to drums, percussion, and sampled material.

The OS v2.0u firmware adds a number of significant improvements and new features over the original RZ-1 operating system.

One of the most useful additions is On-the-Fly Pattern Switching, which allows patterns to be changed in real time during playback. With the original firmware, pattern changes required stopping playback first, making live performance and pattern creation far less intuitive.

Another major improvement addresses a limitation of the original firmware. The stock RZ-1 often leaves a very small gap at the beginning of sampled sounds. OS v2.0u adds sample start point adjustment, allowing unwanted silence to be trimmed for tighter and more accurate sample playback.

The firmware also introduces Sample Reverse, greatly expanding the creative possibilities for sound design and sequencing.

Additional OS v2.0u features include:

• Adjustable Sample Attack
• Accent Lock
• Independent MIDI Transmit and Receive Channel Assignment
• Sample Reverse Playback
• Local On/Off
• Metronome On/Off

• Upgraded with a new LED-backlit LCD display for improved brightness and long-term reliability.

• The main board and power supply board have been fully recapped.

• The internal memory backup battery has been replaced with a new one. A battery socket has been installed, allowing future battery replacements without soldering.

• A DIP-28 socket has been installed for the EPROM, making future firmware updates simple and completely solder-free.

• All potentiometers and switches have been cleaned and lubricated.

• All I/O jacks have been cleaned.

• Overall, the unit is in excellent cosmetic condition. There is a small crack on the right corner of the casing (see photo #10). This does not affect operation in any way, and the area has been reinforced to help prevent further cracking.

• Equipped with a built-in 100V / 120V / 220V / 240V voltage selector. The unit can be set to your local mains voltage before shipping upon request.

Shipping:

• Ships with tracking for safe and secure delivery.