From Fil 'SoloDallas', just an introductory word for our friend Roe. Roe has been on the hunt for AC/DC's tone at least since I have been; that means, years and years, if not decades. So it's not something it started yesterday. It's been a long way coming. Roe's original link (added) denotes him being a researcher (like us) and collector of various information, scattered around places and time. He has been an inspiration for us at SoloDallas as well as a source of primary information. It would not be fair reproducing his work here without these lines of mine. May information be divulged honestly and properly for the sake of us all, always.
Reproduced from: The Evolution of the 100W Circuit: From JTMs to JMP Superleads
By Roe Fremstedal ©2011-2012
This article tries to give an overview over the early Marshall 100 watt amplifiers by piecing together available information and shedding new light on transitional models from 1967. The first 100 watt amps – known today as “JTM45/100s” – used “JTM45” plexi faceplates and white “Super 100 Amplifier” back-plates. However, the 100 watt PA amps used “JTM100” faceplates. In 1967 several changes were made. First, the plexi “Superlead” and “Superbass” backplates were introduced, then the so-called “Black Flag” “J.T.M.” plexi faceplate was used in a transitional period. Finally, the “JMP” plexi faceplate replaced the earlier faceplates. The main stages in the evolution of these early 100 watt amps are: 1. Prototypes (1965) 2. Amps with dual output transformers (1965) 3. First amps with single output transformer (1966) 4. First EL34 amps (1967) 5. Second series of EL34 amps with dual rectifiers (1967) 6. JMP faceplate and new power supply (1967) 7. New Superlead circuit (1968) 8. New chassis and higher filtering (1969) 9. Yet another chassis, last plexis (1969) 10. Aluminium panel amps (1969-)
A tribute to the man & guitar who created the soundtrack of Australian rock’n roll.
Growing up in a country town, AC/DC was a big part of the local music culture. It was either on the radio, or blasting out of someone’s car stereo down the main street or being played by every local cover band at the pub. I can’t remember the first time I heard them… they were always there. And the older I get, the more I appreciate their genius.
The Black Flag JTM50 is a rather rare and coveted after amplifier made by Marshal between 1966 and 1967. It was one of the transitional steps between the JTM45 amps and the plexi panel JMPs and later metal faces. During the short period of time it was produced, the JTM50 saw a few important spec changes that would be a precedent for further development of the Marshall guitar amps.
"... except what has been forgotten."
Says he. And in fact, the core running underneath is always the good ole SoloDallas team. Same guys as always, but better (only Franz - former product manager - took a long pause, after being the real engine responsible for production and everything else, when we were back in Europe; seems like 100 years ago, now). In these two+ years here in the US I (we) have worked so hard that I can hardly believe it. I forget how many hours a-day; every day, on Saturdays, Sundays included, non-stop. Hectically. Then I’d take off for a while - but could never not-think about SoloDallas stuff. Just got to do it.