JOLT (1975)
The rare JOLT computer in Achim Baqué’s vintage computer collection.
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Hardly anyone knows the JOLT, although it was one of the first microcomputers and was based on the 6502. This computer is not to be confused with the SuperJOLT, which appeared later and is more common.
I had only seen this computer once in David Larsen's former Bugbook Museum. Nowhere else.
Ray Holt developed it and even Atari used this tiny computer to develop a console. I was in contact with Ray Holt for about 10 years and always hoped to buy a JOLT from him, but Ray only ever wanted to sell his entire collection.
All my attempts in specialised forums and with well-known collectors were unsuccessful. Most of them did not know the computer and no one had ever seen it in person.
It was maddening.
But in 2025 I finally found an owner of a working JOLT computer. His brother had bought the computer in 1975. After a few conversations, I was finally able to purchase the JOLT and add it to my collection. Ray Holt offered to sign it and I hope that an opportunity will present itself. In any case, I would like to thank Ray Holt for the many pleasant conversations and wish him every success in selling his fantastic collection.
About the JOLT computer and Ray Holt
The JOLT computer is an early microcomputer designed by Ray Holt, an American computer engineer and pioneer in integrated circuit design. Developed in the early 1970s, the JOLT holds a special place in the history of computing because it was among the first microcomputers that hobbyists and engineers could build and use for personal projects and educational purposes.
Ray Holt is also well known for his groundbreaking work designing what many consider the the MP944 chipset, often described as one of the earliest microprocessor implementations, which was part of the F-14 Tomcat fighter jet’s guidance system. After this classified work, Holt continued to explore microprocessor applications for the civilian market.
In 1974, Holt and his company, Microcomputer Associates Inc., introduced the JOLT. The JOLT was a single-board computer kit that used the MOS Technology 6502 microprocessor , the same chip that would later power famous systems such as the Apple-1, Apple II, Commodore PET, and Atari consoles.
The JOLT was aimed at experimenters, engineers, and students who wanted to learn about microprocessor technology. It provided an affordable way to gain hands-on experience at a time when personal computers were not yet widely available. The JOLT featured a simple design, expandable hardware, and could be programmed in machine code or assembly language.
While the JOLT never reached mass-market fame like later microcomputers, it played an important role in spreading early microprocessor knowledge. Ray Holt’s contribution through projects like the JOLT helped lay the groundwork for the explosion of the personal computer industry that followed shortly after.
Later Ray Holt designed together with Manny Lomas the VIM-1 'Versatile Input Monitor'. This was later renamed to SYM-1 'Synertek Microcomputer' after Synertek Systems bought Ray Holt's and Manny Lomas' company Microcomputer Associates Inc. The SYM-1 single board computer was very successful.
Today, the JOLT and Ray Holt’s pioneering work are recognised by computing historians as key stepping stones in the evolution from mainframes to the personal computers we know today.
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