This posting is intended to introduce the XP series of pre-amplifiers and amplifiers produced by SR&D between 1989 and 1994. The XP series integrates the technologies of the Rockman X100 and the Rockmodules into an all in one system that can be programmed with up to 100 configurations.
The XP series started in 1989 as a rack mounted preamplifier called the XPR that was intended for direct connection to a full range PA system. There is a three band EQ that allows pre-distortion changes to the EQ. You can also mix the clean signal with the distorted signal. The distortion is followed by a second 5 band EQ. The effects follow, including a stereo chorus that has a programmable sweep speed, along with a reverb.
The release of the XPR in 1989 was complemented by the release of the related XP100. The XP100 is a complete amplifier that packages the XPR pre-amplifier with a 2x50 watt stereo amplifier and 6 inch speakers. The speakers are in a dual enclosure that can be separated.
1991 brought a number of XP series products, that were all produced in small numbers. A low-noise update to the XPR was released, called the XPRa. Similarly, the XP100a combo was released as a low noise version of the XP100. Another combo was released in 1991. Instead of six inch speakers like the XP100 and XP100a, 12 inch speakers were installed, in a 2x12 single cabinet configuration. This product was called the XP212. A head version was also produced, called the Rockman Superhead. It is basically a XP100, without the speakers. Due to the small production numbers, the XPRa, XP100a, XP212 and Superhead are extremely difficult to find in the after market.
Another product that deserves mention is the A12-50 combo, released in 1993. It is not part of the XP series, but is similar to the XP100 and XP212 in the respect that it's a combo. It is a two channel (distortion and clean) 1x12 50 watt mono combo. The A12-50 uses the Rockman Ultimatum circuit, which is also used in the Rockman UDG stomp box. It lacks the chorus and reverb of the other Rockman products, but provides an effects loop for using external effects. It is probably the most conventional of the Rockman guitar amplifiers.
1994 marked the end of development for the XP Series. The rights for the Rockman line were sold to Dunlop, and Tom Scholz shutdown SR&D company operations. Despite that, the XP Series lives on, still being used by musicians and exchanged by collectors.