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This is an article I've been piecing together over the last few months. I play guitar as a hobby and do some writing from time to time. The SR&D product line is interesting, so I picked on it. I based a lot of the article on material from rockman.fr and the user manuals. I hope you find it interesting. If you read my earlier articles on the Rockman Headphone amplifiers, Rockmodules and XP series, this is a compilation with some additions.
When I picked up the the recently released Boston album "Life, Love & Hope", the cover confirmed what I think many have known for a long time. I can only speak for myself, but I think it's all about the guitars. That's not to say that the other performances on the album are not important. It's just that the guitar has always been the center of gravity for Boston albums. The guitars and musicianship are part of that, but so is the signal chain after the guitar. The story of that signal chain may not be as well known. I think that is a story worth trying to tell.
This Boston guitar gear story begins with Tom Scholz. He was educated as an engineer and did enormous amounts of technical work to achieve the guitar sound that is such a trademark of Boston. Scholz went so far as to start a company, called Scholz Research & Development (SR&D), Inc. The company was formed in 1980. Over the years SR&D produced a number of products. This article only tells part of the story of those products, but I hope it will convey the depth of engineering that took place at SR&D. Now on to the first product, the Power Soak.
The Power Soak was an attenuator, that you would put inline between your amplifier and speakers. Once you had a sound dialed in that worked, you could then use the Power Soak to dial in the output level. This however was just the beginning of what SR&D would produce. The Power Soak was followed by the Rockman.
The Headphone Amplifiers
The original Rockman was released in 1982. It was a headphone amplifier for the guitar, but it was more than a simple amplifier. It included a compressor, cabinet simulation, stereo chorus and reverb. It had two clean sounds, along with "Edge" and a distortion mode. The two clean modes were differently EQ'd, "Clean 1" targeted the electric guitar, while "Clean 2" was recommended for a wider range of use, including acoustic guitar, keyboard and vocals. The "Edge" setting produced what is described as "subtle" distortion, that cleans up when playing softly. The chorus and reverb are tied together, both being on when the switch was set to normal. You can disable the chorus or reverb, but not both at the same time. The Rockman requires eight AA batteries or an adapter for power.
1983 brought a different kind of Rockman. The Rockman Ultralight was a more economical alternative to the Rockman. It was very similar to the Rockman, but lacked the reverb. Uniquely, the chorus could be disabled, providing a dry output from the amplifier simulator. Both the original Rockman and Ultralight models were continued until 1984.
1984 brought a new family of Rockman products. This included the X100, Soloist and Bass Rockman. The X100 was very similar to the original Rockman in its feature set, but used a different clipping stage in the amplifier simulation.
The Rockman Soloist was positioned as a lower cost Rockman product. It did not have the "Clean 2" voice. It also had different choices for effects, including a setting for chorus and a "stereo" setting that had a fixed 25 millisecond delay. It could be set to "Mono" output, removing all the effects.
The Bass Rockman, as the name implies, was for Bass players. It featured clean and distortion modes, including chorus. Dry output is available when the chorus switch is set to "off". There are three EQ presets for what is described as "Fat", "Mid" and "Bright". There is a high frequency clipper, recommended for use with a pick or "snapping" the strings. There is a high frequency compressor and sustain switch, primarily intended for changing the sustain of the bass in different ways. The 1984 family continued to be produced until 1994.
The Ace family is a much simpler type of Rockman headphone amp. It doesn't have effects and uses a single 9-volt battery or power supply. The focus was having a more cost effective product. The Guitar and Bass Ace were first released in 1990. The Metal Ace was released in 1994. The Guitar Ace and Metal Ace have identical controls, but the Metal Ace is advertised to have a "brighter" sound. The amplifier distortion is toggled using the "cln/dist" button. The character of the distortion can be changed with the "semi/hvy" button. Semi-distortion behaves much like the "edge" setting is described to, in the Rockman and X100 product. The Bass Ace is intended for Bass players. It has the most spartan controls, including mid and treble boost buttons. If the Ace family seems familiar, it's still produced and sold by Dunlop. Unlike the rest of the Rockman line, you can buy them new.
The Rockmodules
The Rockmodules brought the Rockman sound to the studio and stage in a more serious way. The Rockmodules were a line of professional quality, rack mount guitar effects, introduced in 1986. There are roughly three categories of Rockmodules, the amplifier simulators, the sound processors and the control devices.
The amp simulators include the Sustainor and Distortion Generator. The Sustainor was first released in 1986. The Sustainor includes a preamp/compressor, a noise gate, distortion and filters, along with a cabinet simulation. Another feature is the auto-clean circuit that allows controlling the guitar distortion by adjusting the guitar volume knob.
The Distortion Generator is a related product that that was released in 1987. The Distortion Generator includes compression, distortion and cabinet simulation circuitry. Compared to the Sustainor, the Distortion Generator lacks the noise gate and external loop, but includes a three band pre-distortion EQ.
The sound processors include the EQ, Compressor, Smart Gate, Chorus, Echo and Stereo Chorus/Delay. The Stereo Chorus/Delay was released in 1986. It can be used as either a chorus or delay. The chorus effect can be mono or stereo. The Chorus/Delay is used for doubling, slap-back and reverb-like short echoes. Combining the Stereo Chorus/Delay with a Sustainor provides a complete system for recording guitar. 1987 brought the Instrument EQ, Stereo Echo and Stereo Chorus.
The Instrument EQ was specifically designed for use with the Sustainor and Distortion Generator. The EQ frequencies were tailored for use with musical instruments, putting an emphasis on the mid range frequencies. Its intended place in a Rockmodule lineup is after the Sustainor or Distortion Generator, but before the chorus and echo effects. It can also be used as a pre-distortion EQ, when placed in the Sustainor effects loop.
The Rockman Stereo Echo is an analog delay. It can be used to provide "slap back" echo when no feedback is used. Increasing the delay time and adding feedback provides standard echo effects. It has stereo inputs, or a mono input if only the left input is used. One possible lineup is to put the Stereo Echo after the Stereo Chorus. The Stereo Chorus was introduced in 1987, following the Stereo Chorus/Delay in the Rockmodule lineup. It is a dedicated analog chorus and adds foot switchable controls for long-chorus and sweep stop.
The Rockman Guitar Compressor is a professional quality compressor tailored for use with guitars. Since many of the Rockman products include a compressor (Headphone amps, Sustainor, Distortion Generator, XP Series, Acoustic Guitar Pedal and Ultimatum based products), this effect is primarily intended to add compression when it's not provided by other equipment in the signal chain. The Rockman Smart Gate is a dedicated noise gate that builds on the noise gate technology in the Rockman Sustainor.
The control devices include the Midi Octopus and Dual Remote Loop. The Midi Octopus is used for controlling other effects. It can be used with a Midi pedal board, or be controlled by a Midi sequencer. The Dual Remote Loop is used to interface effects and amplifiers that can't controlled by other means.
The XP series
The XP series started in 1989 as a rack mounted programmable pre-amplifier 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.
Final Products
A couple of the final products produced by SR&D were based on what was called Ultimatum. A third product, the Acoustic Guitar Pedal was also produced toward the end.
The Ultimatum products are based on two distinct clipping stages in series. The first part of the Ultimatum circuit has a compressor, clipping stage and cabinet simulation. A second clipping stage simulates the saturation of a power section in an overdriven tube amplifier. Both the A12-50 combo and Ultimatum distortion generator are based on this circuit.
The A12-50 combo was released in 1993. It is a two channel (distortion and clean) 1x12 50 watt mono combo. 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.
The Ultimatum Distortion Generator was introduced in 1994. It was designed primarily for use as a distortion with a standard guitar amplifier. It can also be used as a pre-amplifier for directly connecting a guitar to a mixing console.
The Acoustic Guitar Pedal was released in 1994, designed for clean guitar work. It is basically a compressor with bass and treble controls. It's intended to make an electric guitar sound more like an acoustic guitar.
SR&D End Game
In 1995, Scholz sold the Rockman line to Dunlop Manufacturing, Inc. and closed SR&D. Over the years, the after market has actively repaired, refurbished, exchanged and continued using the remaining SR&D products. There are collectors who specialize in this gear.
When I picked up the the recently released Boston album "Life, Love & Hope", the cover confirmed what I think many have known for a long time. I can only speak for myself, but I think it's all about the guitars. That's not to say that the other performances on the album are not important. It's just that the guitar has always been the center of gravity for Boston albums. The guitars and musicianship are part of that, but so is the signal chain after the guitar. The story of that signal chain may not be as well known. I think that is a story worth trying to tell.
This Boston guitar gear story begins with Tom Scholz. He was educated as an engineer and did enormous amounts of technical work to achieve the guitar sound that is such a trademark of Boston. Scholz went so far as to start a company, called Scholz Research & Development (SR&D), Inc. The company was formed in 1980. Over the years SR&D produced a number of products. This article only tells part of the story of those products, but I hope it will convey the depth of engineering that took place at SR&D. Now on to the first product, the Power Soak.
The Power Soak was an attenuator, that you would put inline between your amplifier and speakers. Once you had a sound dialed in that worked, you could then use the Power Soak to dial in the output level. This however was just the beginning of what SR&D would produce. The Power Soak was followed by the Rockman.
The Headphone Amplifiers
The original Rockman was released in 1982. It was a headphone amplifier for the guitar, but it was more than a simple amplifier. It included a compressor, cabinet simulation, stereo chorus and reverb. It had two clean sounds, along with "Edge" and a distortion mode. The two clean modes were differently EQ'd, "Clean 1" targeted the electric guitar, while "Clean 2" was recommended for a wider range of use, including acoustic guitar, keyboard and vocals. The "Edge" setting produced what is described as "subtle" distortion, that cleans up when playing softly. The chorus and reverb are tied together, both being on when the switch was set to normal. You can disable the chorus or reverb, but not both at the same time. The Rockman requires eight AA batteries or an adapter for power.
1983 brought a different kind of Rockman. The Rockman Ultralight was a more economical alternative to the Rockman. It was very similar to the Rockman, but lacked the reverb. Uniquely, the chorus could be disabled, providing a dry output from the amplifier simulator. Both the original Rockman and Ultralight models were continued until 1984.
1984 brought a new family of Rockman products. This included the X100, Soloist and Bass Rockman. The X100 was very similar to the original Rockman in its feature set, but used a different clipping stage in the amplifier simulation.
The Rockman Soloist was positioned as a lower cost Rockman product. It did not have the "Clean 2" voice. It also had different choices for effects, including a setting for chorus and a "stereo" setting that had a fixed 25 millisecond delay. It could be set to "Mono" output, removing all the effects.
The Bass Rockman, as the name implies, was for Bass players. It featured clean and distortion modes, including chorus. Dry output is available when the chorus switch is set to "off". There are three EQ presets for what is described as "Fat", "Mid" and "Bright". There is a high frequency clipper, recommended for use with a pick or "snapping" the strings. There is a high frequency compressor and sustain switch, primarily intended for changing the sustain of the bass in different ways. The 1984 family continued to be produced until 1994.
The Ace family is a much simpler type of Rockman headphone amp. It doesn't have effects and uses a single 9-volt battery or power supply. The focus was having a more cost effective product. The Guitar and Bass Ace were first released in 1990. The Metal Ace was released in 1994. The Guitar Ace and Metal Ace have identical controls, but the Metal Ace is advertised to have a "brighter" sound. The amplifier distortion is toggled using the "cln/dist" button. The character of the distortion can be changed with the "semi/hvy" button. Semi-distortion behaves much like the "edge" setting is described to, in the Rockman and X100 product. The Bass Ace is intended for Bass players. It has the most spartan controls, including mid and treble boost buttons. If the Ace family seems familiar, it's still produced and sold by Dunlop. Unlike the rest of the Rockman line, you can buy them new.
The Rockmodules
The Rockmodules brought the Rockman sound to the studio and stage in a more serious way. The Rockmodules were a line of professional quality, rack mount guitar effects, introduced in 1986. There are roughly three categories of Rockmodules, the amplifier simulators, the sound processors and the control devices.
The amp simulators include the Sustainor and Distortion Generator. The Sustainor was first released in 1986. The Sustainor includes a preamp/compressor, a noise gate, distortion and filters, along with a cabinet simulation. Another feature is the auto-clean circuit that allows controlling the guitar distortion by adjusting the guitar volume knob.
The Distortion Generator is a related product that that was released in 1987. The Distortion Generator includes compression, distortion and cabinet simulation circuitry. Compared to the Sustainor, the Distortion Generator lacks the noise gate and external loop, but includes a three band pre-distortion EQ.
The sound processors include the EQ, Compressor, Smart Gate, Chorus, Echo and Stereo Chorus/Delay. The Stereo Chorus/Delay was released in 1986. It can be used as either a chorus or delay. The chorus effect can be mono or stereo. The Chorus/Delay is used for doubling, slap-back and reverb-like short echoes. Combining the Stereo Chorus/Delay with a Sustainor provides a complete system for recording guitar. 1987 brought the Instrument EQ, Stereo Echo and Stereo Chorus.
The Instrument EQ was specifically designed for use with the Sustainor and Distortion Generator. The EQ frequencies were tailored for use with musical instruments, putting an emphasis on the mid range frequencies. Its intended place in a Rockmodule lineup is after the Sustainor or Distortion Generator, but before the chorus and echo effects. It can also be used as a pre-distortion EQ, when placed in the Sustainor effects loop.
The Rockman Stereo Echo is an analog delay. It can be used to provide "slap back" echo when no feedback is used. Increasing the delay time and adding feedback provides standard echo effects. It has stereo inputs, or a mono input if only the left input is used. One possible lineup is to put the Stereo Echo after the Stereo Chorus. The Stereo Chorus was introduced in 1987, following the Stereo Chorus/Delay in the Rockmodule lineup. It is a dedicated analog chorus and adds foot switchable controls for long-chorus and sweep stop.
The Rockman Guitar Compressor is a professional quality compressor tailored for use with guitars. Since many of the Rockman products include a compressor (Headphone amps, Sustainor, Distortion Generator, XP Series, Acoustic Guitar Pedal and Ultimatum based products), this effect is primarily intended to add compression when it's not provided by other equipment in the signal chain. The Rockman Smart Gate is a dedicated noise gate that builds on the noise gate technology in the Rockman Sustainor.
The control devices include the Midi Octopus and Dual Remote Loop. The Midi Octopus is used for controlling other effects. It can be used with a Midi pedal board, or be controlled by a Midi sequencer. The Dual Remote Loop is used to interface effects and amplifiers that can't controlled by other means.
The XP series
The XP series started in 1989 as a rack mounted programmable pre-amplifier 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.
Final Products
A couple of the final products produced by SR&D were based on what was called Ultimatum. A third product, the Acoustic Guitar Pedal was also produced toward the end.
The Ultimatum products are based on two distinct clipping stages in series. The first part of the Ultimatum circuit has a compressor, clipping stage and cabinet simulation. A second clipping stage simulates the saturation of a power section in an overdriven tube amplifier. Both the A12-50 combo and Ultimatum distortion generator are based on this circuit.
The A12-50 combo was released in 1993. It is a two channel (distortion and clean) 1x12 50 watt mono combo. 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.
The Ultimatum Distortion Generator was introduced in 1994. It was designed primarily for use as a distortion with a standard guitar amplifier. It can also be used as a pre-amplifier for directly connecting a guitar to a mixing console.
The Acoustic Guitar Pedal was released in 1994, designed for clean guitar work. It is basically a compressor with bass and treble controls. It's intended to make an electric guitar sound more like an acoustic guitar.
SR&D End Game
In 1995, Scholz sold the Rockman line to Dunlop Manufacturing, Inc. and closed SR&D. Over the years, the after market has actively repaired, refurbished, exchanged and continued using the remaining SR&D products. There are collectors who specialize in this gear.