1978 Marshall 100w Super Lead model 1959. Made in UK, serial number 05443K. This is mostly original with the obvious exception of the added master volume. One selector pin on the back has also been replaced. The power tubes are a set of great sounding EI EL34, the master volume mod didn't turn this into a gain monster, it's perfect for those big fat crunchy rock tones à la AC/DC at lower volumes. The amp was given a clean bill of health by our service technician, but the original filter caps might need to be replaced further down the road, even though the amp performs great and very silently.