Eric Clapton’s performance and sound on the John Mayall & The Blues Breakers self-titled album from 1966 was so seminal that the 30 Watt 2x12 Marshall amplifier combo he used on the record was soon nicknamed “Bluesbreaker” after the band. This Softube plug-in model is based on Marshall’s own specimen of a Series 1 Bluesbreaker model 1962 amp, kept in pristine shape by Marshall since 1965.

In the making of this plug-in, Softube worked closely with Marshall’s product experts as well as legendary engineer Tony Platt (AC/DC, Iron Maiden, Motorhead and many more) to ensure that the Bluesbreaker was captured in the best possible manner.

About the amp

Guitarist lore will have it that the idea for the Bluesbreaker actually came from Eric Clapton himself, as he wanted an amplifier that could fit in the trunk of his car. This myth has since been rebutted, and a much more likely reason for the Bluesbreaker to be conceived was that Jim Marshall simply wanted an amp that could compete with the very popular Vox AC30, which was also a combo amplifier with a 2x12 speaker configuration.

The Bluesbreaker’s amplifier section is identical to the standalone JTM45 Tremolo amplifier head, which was Jim Marshall’s first amplifier model ever (yes, in spite of its product name, the JTM45 was a 30 watt amp). This was built into a Baltic birch cabinet with two 12 inch Celestion T652 15 ohm speakers, although there were specimens equipped with the 8 ohm version of that speaker instead, the T650. This goes for the particular unit used for this plug-in. The T650 speaker was Celestion’s stock version of the blue alnico speaker T530, known for its use in Vox amplifiers where it contributed substantially to the sound. The T650/T652s were silver sprayed, and Marshall put their own gold colored sticker on top of Celestion’s sticker. The fact that the Bluesbreaker had an open back cabinet with alnico speakers set it very much apart from most other Marshall cabinets, which are usually closed designs equipped with ceramic speakers.


The Bluesbreaker has two channels, with a high and low input each. A lot of sonic variation can be obtained from connecting these channels with a patch cord, which is faithfully modeled in this plug-in.

1. On/Off and Standby

2. Tremolo Speed

3. Tremolo Intensity

4. Presence

5. Bass

6. Middle

7. Treble

8. Loudness I High Treble

9. Loudness II Normal

10. Patch Switching


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Amplifier Parameters

The functionality of the front panel controls corresponds exactly to that of the real amplifier.

On/Off and Standby: Turns the amplifier on or off.

Tremolo Speed: Sets the speed of the built-in tremolo.

Tremolo Intensity: Sets the intensity (depth) of the built-in tremolo. Please note that the Tremolo is only active for Input 2.

Presence: Increases the amount of presence—a treble boost accomplished by reducing the amount of high frequencies being subjected to negative feedback in the power amp section.

Bass, Middle and Treble: Tone controls that determine the frequency content from the amplifier.

Loudness I High Treble: Sets the volume of Channel 1.

Loudness II Normal: Sets the volume of Channel 2, the only channel that has Tremolo.

Patch Switching: Provides different combinations of high and low inputs for Channel 2 and Channel 2 separately. Clicking one of the four inputs selects it as the main input from the guitar (black cable). Clicking the selected guitar input again rotates between the available patching patters (with the short black/white fabric-covered patch cable).

Patch Switching

By patching the inputs you will get different input gain and different tonality from the amp. INPUT II is dark sounding, and by combining it with INPUT I you can work the Volume knobs almost like an EQ.

The most common way of patching is going into Input I at the top, and patching from the low Input I to the top Input II, but feel free to experiment!

Click on the inputs to switch settings, see “Patch Switching” on page for more info.

Input Channels

Input I (top): Bright, high gain. 1 MOhm input impedance.

Input I (bottom): Bright, low gain. About 100 kOhm input impedance.

Input II (top): Dark, high gain. 1 MOhm input impedance.

Input II (bottom): Dark, low gain. About 100 kOhm input impedance.

Note that clicking any parameter name on the front panel resets the corresponding knob to its default position.


Channel Strip Parameters

The channel strip can be opened by clicking the right hand wood panel with the green Channel Strip sticker. Clicking this again closes the channel strip.

1. Presence

2. Main Out VU Left

3. Clip Meter

4. Main Out VU Right

5. Cabinet Microphone Select

6. Pan

7. In

8. Channel Fader

Channel Strip Parameters.jpg

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Main Out Level VU and clip meters: Indicates the plug-in’s Main Out level. The red LED marked OL indicates that the channel is overloading and that the Main Out Volume knob should be turned down.

Main Out Volume: Sets the overall output level of the plug-in without affecting the sound.

Cabinet Microphone Select: Set which set of microphones you want to use, with Valve, FET or Dynamic mics up close. See next section for a description of the mics and position.

In: Activates/deactivates each microphone channel.

Pan: Places the microphone channel in the desired position in the stereo panorama.

Channel Fader: Adjusts the volume of the respective microphone channel.


Cabinet and Microphones

The Bluesbreaker was recorded through the original speakers, Celestion T650, branded with the original Marshall block-logo, through a variety of microphones at the legendary Strongroom recording facility in London, UK. The label Valve, FET and DYnamic refers to the type of microphones used near-field.

Valve Microphones

Selects the microphone set with valve (tube) condenser microphones in the near field. As indicated by the tape markings above each channel, these are Neumann U67s, while Coles 4038 and Telefunken ELA M 251 are used for the room.

FET Microphones

Selects the microphone set with FET condenser microphones in the near field. As indicated by the tape markings above each channel, these are Neumann U87s, with SE Electronics Voodoo VR2 and Telefunken ELA M 251 for the room.

Dynamic Microphones

Selects the microphone set with dynamic microphones in the near field. As indicated by the tape markings above each channel, these are Shure SM57 and Sennheiser M380, with Coles 4038 and Telefunken ELA M 251 for the room.

Off (No Cabinet or Microphone)

Sets the cabinet and microphone emulation in bypass, so that only the direct sound from the Bluesbreaker’s amp section is heard. This is usually not regarded as a very pleasant sound, but the setting is useful for combining the amplifier with other cabinet/microphone models, such as the ones available in Softube Vintage Amp Room, Bass Amp Room, Metal Amp Room, Half Stack or Bass Amp Room 8x10. In all these plug-ins, the amplifier section can be bypassed. This would be the recommended setting, when combining the Marshall Bluesbreaker amp section with the cabinet in either of those plug-ins.


Marshall Bluesbreaker 1962 in Amp Room


When purchasing this product, you automatically gain access to running the plugin as modules inside the Amp Room platform. The amp and cab sections are divided into two separate Amp Room modules so they can be matched and arranged together with any other native Amp Room module or other Amp Room-ready modules that you might own.