Master Effects Super Eight Hundred

The Master Effects Super Eight Hundred is a bass preamp pedal that puts the maker's interpretation of the 1980s Gallien-Krueger 800RB bass amplifier into a pedalboard-friendly box. Instead of modeling the whole amp, it recreates the preamp and EQ section that gave the 800RB its character, so a player can run it into a clean power amp, an interface, or the front of another amp and get that voicing at pedalboard scale¹.

The core of the pedal is a 4-band EQ, an active gyrator equalizer with boost and cut capabilities, plus a set of tone-shaping toggles that work at the first gain stage before the EQ. It is assembled by hand in Calgary, Alberta, Canada, and priced at $229 US plus shipping¹.

What it does to your sound

Master Effects describes the Super Eight Hundred as its interpretation of the 800RB preamp, with the same tone-shaping approach as the amp it comes from. The Lo Cut, Mid Contour, and Hi Boost toggles shape the fundamental tone at the first gain stage, before the signal reaches the equalizer, which is how the original amp's voicing controls work: you set the character of the gain first, then fine-tune with the EQ¹.

The 4-band EQ is an active gyrator equalizer with boost and cut capabilities. A gyrator is a circuit that behaves like an inductor using op-amps and resistors, which lets each band cut or boost around its center frequency, and it is a common approach in amp-style EQ stages¹.

The controls and toggle switches

The pedal has seven knobs and four toggle switches¹.

The four toggle switches control Lo Cut, Mid Contour, Hi Boost, and overall Boost. The first three are tone-shaping switches that set the fundamental character at the first gain stage, before the EQ. The boost toggle switch engages or bypasses the boost control, so you decide whether the Boost knob is part of your sound before you ever touch the footswitch¹.

Power, bypass, and build

The pedal uses a standard boss-style 9V power supply, the same 9V DC supply most pedalboards already carry. Bypass is soft touch relay true bypass, so the signal passes around the circuit when the pedal is off and the switch action is quiet. The whole pedal is housed in a 125B enclosure with top-mounted jacks, which keeps the footprint narrow on a pedalboard¹.

Each pedal comes with a 1 year warranty on parts and labor, excluding damage from an improper power supply or misuse¹.

The Super Eight Hundred Plus

Master Effects also makes the Super Eight Hundred Plus, which the maker says has the exact same tone as the Super Eight Hundred but adds the features the original amp had that the smaller pedal leaves out².

• Footswitchable boost: the boost moves from a toggle switch to a footswitch, so you can engage it while playing²
• Biamping: with the biamp switch on you can select the crossover frequency, with independent volume controls for the high and low frequencies, mirroring the biamping feature found on the original amplifier²
• 10dB pad²
• XLR DI: a full sized XLR DI jack as found in the original amp, for sending a balanced DI signal direct to the board or an audio interface²

The Plus is currently on Version 2, released in December 2025, which added the biamping feature and the 10dB pad. It is built on a professionally assembled FR4 PCB with UV printed artwork².

For a player deciding between the two: the Super Eight Hundred is the smaller, simpler route to the 800RB preamp tone, while the Plus is the closer functional match to the amp, with the DI and biamp options the original offered¹².

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