Boutique amp maker BC audio has released the Bel Air 40, a five- to 40-watt, all-tube guitar amp with unique power section controls.

The brand claims the amp’s front panel controls “let the player reach inside the amp, so to speak, and re-wire the power section.” To take a closer look at these features we’ve broken them down into two categories: Power Tube Configuration Switches and Extended Power Section Control.

Power Tube Configuration Switches

“Quad/Pair”

• Selects a combination of four or two power tubes.
• Pair mode: Serves as a half-power switch.
• Quad mode: At full power, tone becomes more punchy.

“Pentode/Triode”

• Sets the power tubes’ operating mode.
• Triode mode: Reduces power by half for a smooth and loose feel.
• Pentode mode: Full power for a tighter and cleaner feel.

“Fixed Bias/Cathode Bias”

• Selects the power tubes’ bias.
• Fixed Bias mode: ‘Crispier’ and sharper tone.
• Cathode Bias mode: More compressed and a ‘browner’ tone.

Extended Power Section Control

“Presence” knob

• Boosts treble levels to achieve a classic amp chime.

“Cut” knob

• Brings down the power tubes’ high end.

“Negative Feedback” (NFB) switch

• Alters the damping and open-loop volume of the power section, with a zero setting enabling the user to hear the power tubes in their raw form.

Elsewhere, the amp comes with a three-band EQ, a bypass option, a “Volume” knob and a “Body” knob that shapes the amp’s low-mid frequency response. There’s a three-way “Bright” switch that offers two additional levels of treble response. In terms of tubes, the Bel Air 40 relies on a set of two 6SL7GT octal preamp tubes and four configurable 6V6GT power tubes that produce rich and warm tones.

The Bel Air 40 is also available with 2×12-inch speaker cabinets.

Hear the amp in action here:

Retails at $2900. More information at bcaudio.com.