The first ZX Spectrum was developed by Sinclair in 1982. It was released as one of the first available at home computers in UK history. The hardware was designed by Richard Altwasser of the Sinclair research department, and the outer shell of the computer was created by Rick Dickinson, one of Sinclair’s industrial designers. Since its initial release, eight other models were released within ten years.
The Spectrum is much like the Commodore in the United States in that it was the first widely distributed home use computer to come out on the market. The release of the Spectrum sparked a nationwide surge in the computer and technologies industry because all of a sudden everyone was manufacturing “aftermarket” parts for the computer and some companies even took to making clones of the system and its housing units. In around five million of these computers were sold nationwide in the ten years after the release of the Spectrum and the popularity of this product prompted the founder to the Sinclair Company, Clive Sinclair, to receive a knighthood for his “services to British industry.” They are now expecting the remodeled version to be released in the U.K at any time now.
ZX Spectrum 16K/48K:
It was originally released on April 23rd in 1982 with the options of 16 KB of RAM for £125 or with 48 KB for £175.
ZX Spectrum 16K/48K had dimensions of 233×144×30 (mm). The original ZX Spectrum is best known for its rubber keyboard, relatively small size and distinctive rainbow motif. Buyers of the 16 KB model were able to purchase an internal 32 KB RAM upgrade, which for the earlier “Issue 1” machines consisted of a daughterboard.
ZX Spectrum +:
Original planning of the ZX Spectrum + started in June of 1984 and was released onto the market the following October. The new ZX Spectrum boasted a QL- style case with an injection -molded keyboard and a reset button. It was possible to interchange the internal components, such as system boards, between the original ZX Spectrum 48K and the Spectrum +. This model retailed for £179.95. Buyers were also given the option to buy a do-it-yourself conversion kit for the older models. This model sold out its previous sibling 2:1; however, there were some retailers who reported failure rates of up to 30%, which was high compared to the normal 5-6% from the older models.
ZX Spectrum 128:
Investronica and Sinclair developed this model mainly for the Spanish market. This was after a tax was placed on all computers with 64 KB of RAM or less. This same law made it mandatory for all computers sold in Spain to support the Spanish alphabet and show all messages in Spanish. Some of the new features for this model are: three channel audio, Midi compatibility, an RS-232 serial port, and RBG monitor port, 128 KB of RAM, 33KB of ROM, improved basic editor and an external keyboard.
ZX Spectrum +2:
After buying the Spectrum range and Sinclair brand in 1986, Amstrad creates the Spectrum +2. This machine featured a spring loaded keyboard a built in cassette recorder, a grey case and dual joystick ports. This version was almost identical to the Spectrum 128 except that those one didn’t have the tape test option and they had altered the ROM due to a copyright message. This copyright message meant that there were some small incompatibility issues. This model retailed for only £ 139-149.
This +2A model was basically just a variation on the +3 model and held a black version of the Spectrum+2. The Spectrum +2A/+3 motherboards were at up so that one could assemble it without the floppy disk controller or corresponding logic with a +2 styled data coder connected. They had originally planned for an additional disk interface to be added, but it never was. If it had been used the +2A would have become a +3 on its operating system menu.
The +3 was very similar only UT boasted a built in three inch floppy disk drive rather than a tape drive. The +3 was built in a black case and retired for £249-199. It was the only system capable of running the CP/M system without additional hardware.
ZX Spectrum +2B/+3B:
The ZX Spectrum +2B and ZX Spectrum +3B were very much the same in design to the Spectrum +2A and +3.The main differences were the electronic changes to the generation of the audio output signal to resolve problems with clipping.