John McIntyre ran Musitech from Calgary in the 80s-90s, and was the developer of the Bluesmaker amplifier. He wrote an article in Feb 1993 issue of Guitar Player describing how to build the amp. The article was one of the most popular ever to appear in GP.
McIntyre also developed the Very Low Gain stereo direct amplifier for studio work, which is now known as the Lexicon. In addition, he developed the Musitech on-board mid boost for guitar called the “Smooth and Creamy”, which is still highly regarded by guitar players. Also an interesting tube Wah.
I am currently researching an amp that John McIntyre built in 1995 for Don Cameron. The donor amp was a 1965 Fender Bandmaster. This amp may be unique, in that in addition to the standard Bluesmaker modifications, McIntyre also fitted the amp with EL34 tubes, replacing the stock 6L6GCs, and a Pentode/Triode switch. The amp also has reverb, master volume, and two channels that are VLG. This was right about the time that John was developing his VLG stereo amp, and this may be an early mono version.
The amp sounds really wonderful. You can read all about it (at least what I know so far), on the HardWay website.
My dad and I hacked up a lovely but slightly modified 1962 (tube recto had been swapped for SS) Bassman to do the Bluesmaker mod back in 1993. It sounded simply wonderful and was well used at fairly loud volumes until late 2014, at which point I retuned it to the 1963 6G6 B circuit. Great amp! My dad also utilized the preamp circuit in conjunction with a cathode biased EL-34 power section with power scaling in an old Stromberg Carlson PA. It sounds great! Really a fun circuit. Kind of the best of Fender and Marshall all in one.