The following is a list of clones of Sinclair Research's ZX Spectrum home computer. This list includes both official clones (from Timex Corporation) and many unofficial clones, most of which were produced in Eastern Bloc countries. The list does not include computers which require additional hardware or software to become ZX-compatible. Many software emulators can fully or partially emulate some clones as well.
Official The only official clones of the Spectrum were made by Timex. There were three models developed, only two of which were released:
Timex Sinclair 2068
The Timex Sinclair 2068 or T/S 2068 (also known as TC 2068 or UK 2086) was a significantly more sophisticated machine than the original Spectrum. The most notable changes were the addition of a cartridge port, an AY-3-8912 sound chip, and an improved ULA giving access to better graphics modes. The T/S 2068 was produced for consumers in the United States, while very similar machines were marketed in Portugal and Poland as the Timex Computer 2068 (TC 2068) and Unipolbrit Komputer 2086 (UK 2086) respectively. A small number of TC 2068s were also sold in Poland.
Timex Computer 2048
The Timex Computer 2048 or TC 2048 was a similar machine to the Spectrum 48K, but with the improved ULA from the TC 2068 (allowing access to the improved graphics modes), Kempston joystick port, and composite video output. Marketed only in Portugal and Poland.
Timex Sinclair 2048
The Timex Sinclair 2048 or T/S 2048 was a never-released variant of the T/S 2068 with 16 KB of RAM.
Inves Spectrum +
A clone of the ZX Spectrum+ developed by Investrónica in Spain in 1986, the Inves Spectrum + was based on the work developed by the company on the ZX Spectrum 128. Released just after Amstrad bought Sinclair Research Ltd, it looked much like a regular ZX Spectrum+, but all the internal components were redesigned. As the ROM was also modified, it has compatibility problems with some games – notably Bombjack, Commando, and Top Gun. A Kempston joystick port was fitted on the rear of the machine. Due to Invéstronica being the distributor of Sinclair's products in Spain, and because Amstrad already had its own exclusive distributor in Spain (Indescomp, later bought by Amstrad itself), Amstrad sued Investrónica in 1987 to cease sales of the computer. The court agreed with Amstrad, but the decision was not issued until 1991, when the computer was discontinued, as the 8-bit computer market in Spain was succeeded by 16-bit computers.
Decibels dB Spectrum+
The Decibels dB Spectrum+ was an official clone of the ZX Spectrum+ for the Indian market, introduced in 1988 by Decibels Electronics Limited, selling over 50000 units and achieving an 80% market share.
Unofficial
British
Harlequin A British clone of the 48K ZX Spectrum, Harlequin was designed and developed by Chris Smith, to aid the reverse engineering of the ZX Spectrum custom ULA chip, and its research documentation. Completed in 2008, it is the first 100% timing compatible clone. Until 2012/13 the Harlequin existed only as a breadboard prototype, but recently, José Leandro Martínez, Ingo Truppel, and others produced a limited number of PCB versions as an exact board replacement for an actual ZX Spectrum.
Czech & Czechoslovak
Bobo64 The Bobo64 was an advanced Czech computer compatible with the ZX Spectrum, developed by Václav Daněček between 1986 and 1987. It has many enhancements over the original ZX Spectrum, including 256×256 graphics with attributes per 8 × 1 pixels, and 512 × 256 graphics. Unlike other Czechoslovak home-made ZX Spectrum clones, the Bobo64 gained some popularity, and was built by dozens of enthusiasts.
Didaktik series The Didaktik was a series of home computers produced by Didaktik in Skalica, in the former Czechoslovakia. The first model compatible with the ZX Spectrum was the Didaktik Gama, based on the U880 or Zilog Z80 processors and the original ULA chip. It was produced in three variants between 1987 and 1989. The Gama has a built-in 8255 chip (used for the Kempston joystick, and also as a printer port) and 80 KB RAM, adding an alternative memory bank from the address 32768 to 65535. The Gama was followed by the cheaper Didaktik M (first variant released in 1990; the second in 1991). The model M had a modernised case, Sinclair and Kempston Joystick ports, and a keyboard with cursors and reset key. The design, however, was of lower quality than the Gama. Its screen aspect ratio and display timing are different from the original ZX Spectrum because the M uses a different ULA chip, compatible with the Belarusian clone Baltik. It ran at 4 MHz. The final model was the Didaktik Kompakt (1991) which integrated all previous M hardware with a 3.5″ floppy disk drive. Unlike previous versions, the Didaktik 192K was an amateur project, partly combining the hardware of the Didaktik Gama and the ZX Spectrum 128K.
Krišpín The Krišpín was a Czechoslovak clone of the ZX Spectrum, developed by František Kubiš at 1984, a student of EF SVŠT (Electrotechnical Faculty of Slovak Technical University) Bratislava. The ULA was designed using discrete 74xx ICs, which resulted in the screen part of RAM being synchronised perfectly, without CPU blocking.
MISTRUM Another Czechoslovak clone of the 48K ZX Spectrum, the MISTRUM, was supplied in kit form. The ROM was modified to include letters with Czech diacritic marks. An article on how to build a Mistrum was published in the Czechoslovak amateur radio magazine Amatérské Radio 1/89.
Nucleon
The Nucleon was a Czech clone of the Pentagon 512K, made by CSS Electronics.
Sparrow 48K The Sparrow 48K is the first modern clone of the ZX Spectrum designed to replace the original motherboard in standard and Spectrum+ case. Production commenced in 2013. In addition to the use of the original ULA chip, this clone was heavily modernised, replacing part of the larger glue logic with one CPLD chip, the entire main memory with one SRAM chip, and all 8 video memory chips with a second SRAM. The TV modulator has been dropped in favour of a video signal, and the PSU was changed and improved. The Sparrow also offers a larger ROM, which can be increased by 16 KB via a switch or a jumper. The successor is the Sparrow SX, with software ROM switching and RTC.
East German
HCX The HCX was a Spectrum clone developed at the Technical University of Magdeburg in 1988.
RR-Spectrum The RR-Spectrum was a privately built East German clone of the ZX Spectrum.
Spectral
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