A landmark year for Jim Marshall was 1987. It marked 25 years in the amplifier business and 50 years in music. This was celebrated with the release of the Silver Jubilee series of amps. The Silver Jubilee series consisted of the 2555 (100 watt head), 2550 (50 watt head) along with other 255x model numbers denominating various combos and even a “short head”. The Jubilee amps were heavily based on the JCM800s of the time, featuring a very similar output section along with a new preamp. Their most publicised feature was the half-power switching, which is activated by a third rocker switch next to the standard “power” and “standby” switches. On the 50 watt model this was reflected in the numbering – 2550 is switchable from 25 to 50 watts – and also reflected Marshall amps’ 25th anniversary and Jim Marshall’s 50 years in music. The amps were trimmed in silver covering, and had a bright silver-coloured faceplate, along with a commemorative plaque.
The Jubilee also featured a “semi-split channel” design, in which two different input gain levels could be set, running through the same tone stack and master volume control. This allowed for a “classic Marshall” level of gain to be footswitched up to a modern, medium to high gain sound, slightly darker and higher in gain than the brasher JCM800 sound that typified 1980s rock music. “The sound of these amps is particularly thick and dark, even on the Marshall scale of things. The gain by today’s standards is medium.
The distortion sound of the Jubilee range is typified by Slash’s live work with Guns N’ Roses. He rarely used anything else live, but oddly the Jubilee did not appear on any Guns N’ Roses studio albums – instead these feature modded JCM800s. It can be heard on some of the Velvet Revolver material though. The Jubilee amps also featured a “pull out” knob that activated a diode clipping circuit (similar to boosting the amp’s input with an overdrive pedal). Other notable Jubilee users include the Black Crowes, John Frusciante (Red Hot Chili Peppers) and Alex Lifeson (Rush), who used it extensively in the recording of Rush’s Clockwork Angels album.
After the Jubilee year, production of the 25xx series amplifiers continued for one more year (with no internal changes), but reverted to a standard Marshall livery of black and gold. These are sometimes referred to as the JCM800 Custom amplifiers.