The Carl Martin Ampster is a fully analog, tube-driven simulator for guitar amplifiers and speaker cabinets, designed for guitarists who want a direct, dynamic and organic amplifier response in a pedalboard format. It can be used with an existing guitar amplifier or as the centre of a compact setup with a direct signal to a mixer or audio interface for recording.

Sound is adjusted using familiar amplifier controls rather than menus and digital modelling. The Ampster responds to picking dynamics and playing style with the immediacy associated with traditional amplifiers, without latency.

Clean and overdrive character

Gain controls the amount of drive, while Master sets the overall output level. The Ampster can deliver a large, rounded clean tone and moves into a musical, British-voiced overdrive at higher Gain settings. The sound is affected by both the guitar and its pickups, preserving the instrument’s own character.

Bass, Middle and Treble are used to balance the tone, while Presence adjusts the upper frequency range. A three-position Voicing switch on the rear provides subtle low-end adjustment, allowing the sound to be adapted to different guitars, pickups or monitor systems.

Cabinet simulation and direct output

The Cabinet footswitch selects between simulations of a 2x12 open-back cabinet and a 4x12 closed-back cabinet. An LED indicates the selected cabinet: red for 2x12 open-back and green for 4x12 closed-back. An external latching footswitch or controller can be connected via the Remote input for remote switching of the cabinet simulation.

The balanced XLR DI output can send the signal directly to a mixer, preamp or DAW system. Ground Lift can help reduce ground loops and noise that may occur in setups with multiple grounded devices. The Ampster also features a buffered, unbalanced Link output for simultaneous connection to a conventional guitar amplifier on stage.

Serial effects loop

The serial FX Loop with Send and Return can be used for pedals placed after the preamp section, including delay and modulation effects. If nothing is connected to Return, the loop is bypassed automatically. The Send output can also be used as an additional pre-EQ, pre-Master volume output.

The Mute footswitch can cut the signal while tuning or making changes to the setup. The Ampster accepts both a guitar connected directly to Input and a signal from a pedalboard.

Technical specifications

• Circuit: Analog, tube-driven
• Bypass: Buffered Bypass
• Cabinet simulations: 2x12 open-back and 4x12 closed-back
• Input impedance: 1 MO
• 1/4" unbalanced output impedance: 1 kO
• Balanced DI output impedance: 600 O
• Signal-to-noise ratio: 56 dB
• FX Send impedance: 1 kO
• FX Return impedance: 100 kO
• Power supply: 9 V DC, regulated, minimum 1 A, 2.1 mm centre-negative
• Power consumption: Maximum 600 mA
• Battery operation: No
• Dimensions: 145 x 120 x 70 mm
• Weight: 0.80 kg

The Carl Martin Ampster combines amplifier response, cabinet simulation, DI and flexible signal routing in one analog pedalboard unit.