Carl Miles showed us some projects he’s working on, including a “super” 1520 expansion (sound, joystick, 512K RAM), the Kilo / KiloZ Rev2 board with ESP32 and VGA, an external 3-inch drive enclosure for the Spectrum +3, an RS‑232 switching mod for the 2050 modem, stereo audio & composite/VGA mods for the 2068, and an Interface‑Zero/Interface‑1 for the 2068. David Anderson updated us on the modern recreation of a 2060-style bus expansion unit built around a Pico/FPGA platform.
The “Super Expansion” (working name: 1520)
Carl gave an an in-depth tour of a two‑board expansion peripheral for the Timex/Sinclair 1000 and 1500 (and Sinclair ZX81). The bottom and top PCBs are purposely split to keep the assembly manageable while packing in a lot of functionality.
Key features
- Direct bus connector compatible with the TS1000 / TS1500 / ZX81-style expansion edge.
- Onboard AY‑series sound chip with stereo mapping: the AY’s channels are assigned so A/B are left/right and C is mixed for mono output. A switching jack disables the speaker when an external line out is inserted.
- Programmable joystick interface with DB9 port (single-button Atari-compatible mapping plus an extra second‑button input). Joystick presses are mapped to keyboard keys via a small configuration program so mappings persist and can be tailored for titles that don’t use cursor keys.
- 512KB RAM packaged as eight 64K banks with jumper selection (or later via IO port). The design includes a battery backup pocket so RAM contents can be preserved between power cycles.
- Shadow ROM area (0–8K) in the RAM chip that can be set to read, write, or disabled: useful for development, alternative boot ROMs, or experimentation.
- M1 / M1‑NOT logic selectable by a switch to allow machine code execution above 32K (critical for certain advanced software and tools).
- TS1510-style cartridge socket replicated to handle classic 1510 cartridges and a separate ROM cartridge port to host multiple ROM images (eight 8K or four 16K banks selectable).
- On‑board LM386 amplifier and speaker with volume control and a line‑out jack for stereo/line output.
- Pass‑through expansion connector so downstream devices can still be stacked.
KiloZ Rev2 — A modern TS1000 motherboard replacement
Carl’s full‑board redesign of the TS1000 is intended to fit in a custom 3D‑printed full‑size KiloZ keyboard case (designed by Ingo Schmied), and also sized to drop into a TS1000 case with some mods. This version brings features:
- ESP32 integration for Wi‑Fi and as a co‑processor; a programming header and external antenna option are included.
- Composite‑to‑VGA/video reconstruction: the ESP32 samples the ULA video output and recreates a crisp VGA signal, avoiding the fuzziness of composite/RF and providing much better display quality on modern monitors.
- 512K RAM and the same bank/jumper circuitry (future IO‑based bank switching planned).
- Audio improvements: AY sound, amp, and an ear/mic pass‑through with an ear‑monitor switch so users can hear loading tones if desired.
- Fixed headers for power switch, reset, status LEDs (M1 state), and joystick/expansion connectors with the footprint matching KiloZ standoffs.
- Composite + stereo audio jack and a combined VGA/power (dongle) approach for a cleaner install.
External 3″ Drive for the Spectrum +3
Carl showed aa compact external enclosure to reuse the smaller 3‑inch floppy drives common in Amstrad/Spectrum +3 hardware. The enclosure is 3D‑printed and hosts a custom PCB to convert the internal drive wiring to an external connector with optional power over the ribbon cable.
RS‑232 / 2050 Mod: Switchable RS‑232 Mode for the 2050 Modem
This mod is an adapter that converts the Timex 2050 modem into a switchable RS‑232 serial port. By latching relays, it can toggle the 2050’s UART lines between the original modem circuitry and a DB‑25 RS‑232 port.
2068 Audio / Video & Stereo Modifications
Several projects target the TS 2068’s audio and video outputs. The main goals are:
- Break out AY channels (A/B/C) as true stereo lines so we can route them separately or mix externally.
- Provide a jack that, when inserted, mutes the internal speaker/load‑noise path—this eliminates the ubiquitous hissing coming from older power supply audio stages.
- Swap or augment the on‑board switching regulator/power stage to reduce hiss and provide cleaner +5V for audio and logic.
- Provide a combined composite + stereo audio dongle that fits existing case holes (no new drilling required) and an option for an external RCA/mini‑jack adapter.
Interface‑Zero / Interface 1 / Twister compatibility for the 2068
This project incorporates the “Interface Zero” (designed by Wes Brzozowski), an adapter to connect the TS 2068 to a ZX Interface 1, with a redesign of the ZX Interface One. This device is intended to let 2068 users put their computer in Spectrum mode and use ZX Interface 1 features, including microdrives.
Modern 2060 Bus Expansion Recreation (a Pico + FPGA appliance)
David shared an update on the modern bus expansion inspired by Timex Sinclair’s 2060 concept. This modular Pico + FPGA platform that extends the 2068 with lots of new features:
- Pico with many GPIO lines to host multiple peripherals.
- FPGA cores for Spectrum, ZX81, and 2068 behaviors so users can load the desired core dynamically.
- SD card file access for load/save, plus native TPI / tape command extension compatibility so legacy save/load commands work without modification.
- Audio: full stereo out, selectable mixes, and line levels for capture.
- Video: VGA and HDMI options via the Pico/FPGA video reconstruction path; crisp 64/80‑column modes implemented by the FPGA with separate RAM so the 2068’s video RAM isn’t stolen.
- USB host capability (mouse/keyboard), RTC, Wi‑Fi, and an on‑board SD interface for software and disk images.
- A 3D‑printed enclosure with a front SD slot, a small OLED status display, and cutouts that echo the original 2060 physical aesthetic.
Cost drivers are obvious: large PCBs, a complex BOM with many SMD parts, and the 3D printed or injection‑molded enclosure. The team is prioritizing PCB assembly at the manufacturer level (turnkey SMT) to reduce hand‑work and error, and they are keeping an eye on tariffs which could increase unit cost sharply.