Randall RD20-112 Diavlo 20W 1x12 All-Tube Guitar Combo Amplifier

Randall RD20-112 Diavlo 20W 1x12 Tube Guitar Combo Amplifier

The Randall RD20-112 Diavlo 20W 1x12 Tube Guitar Combo Amplifier is a two-channel, all-tube amplifier designed for electric guitarists seeking clean tones and high-gain distortion. Featuring 12AX7 preamp tubes, 6V6 power tubes, and a 12-inch Randall speaker, it combines 20 watts of amplification with switchable Tube Boost and flexible tone controls.

Built for guitarists who need tube amplification in a self-contained combo, the RD20-112 accommodates home practice, recording sessions, rehearsals, and live performances. Its Clean channel provides adjustable gain for clear rhythm passages and responsive breakup, while the Overdrive channel delivers saturated distortion for rock and metal. A dedicated Tube Boost function introduces additional overdrive to either channel, allowing players to increase gain without switching amplifiers. Separate channel adjustments and a global Master Volume help balance distortion and listening levels. Shared Bass, Middle, Treble, and Presence controls provide further tonal flexibility for different guitars, pickups, and playing styles.

The amplifier houses a 12-inch Randall RD1250-8 speaker behind a heavy-duty steel grille, eliminating the need for a separate speaker cabinet. Its speaker-emulated balanced XLR output supports direct connections to recording interfaces and live sound mixers, while a Ground Lift switch helps address unwanted ground-loop noise. A Class A discrete instrument-level effects loop accommodates compatible guitar pedals and external processors. Three speaker output jacks provide additional cabinet connection options, subject to Randall's specified impedance requirements. The included RF2T2C two-button footswitch allows remote channel selection and Tube Boost activation, making the amplifier practical for both studio and stage applications.

Key Features

• 20W All-Tube Amplification: Combines 12AX7 preamp tubes and 6V6 power tubes to deliver responsive guitar amplification for rehearsals, recording, and live performance.
• 12-Inch Randall Speaker: Integrated RD1250-8 speaker provides a complete 1x12 amplification system without requiring a separate guitar cabinet.
• Two Footswitchable Channels: Clean and Overdrive channels accommodate everything from lower-gain rhythm playing to heavily saturated guitar distortion.
• Switchable Tube Boost: Adds another stage of tube overdrive to either channel, providing increased saturation for aggressive rhythm parts and lead guitar.
• Four-Control Tone Section: Bass, Middle, Treble, and Presence adjustments allow players to shape low frequencies, midrange definition, treble response, and high-frequency character.
• Class A Discrete Effects Loop: Instrument-level Send and Return connections integrate external effects pedals and signal processors into the amplifier's signal path.
• Speaker-Emulated XLR Direct Output: Balanced output with Ground Lift simulates a miked Randall 4x12 cabinet for recording and professional sound reinforcement.
• Included Two-Button Footswitch: Randall RF2T2C controller enables remote switching between amplifier channels and activation of the additional Tube Boost mode.

Technical Specifications

General Specifications

• Brand: Randall
• Model: RD20-112
• Manufacturer SKU: RD20-112-U
• Series: Diavlo / RD Series
• Product Type: Electric Guitar Combo Amplifier
• Amplifier Technology: All-Tube
• Amplifier Configuration: 1x12 Combo
• Output Power: 20W
• Number of Channels: 2
• Channel Types: Clean and Overdrive
• Additional Operating Mode: Tube Boost
• Channel Switching: Front-Panel Selector or External Footswitch
• Finish: Black

Tube Configuration

• Preamp Tube Type: 12AX7
• Preamp Tube Quantity: 4
• Power Tube Type: 6V6
• Power Tube Quantity: 2
• Amplifier Circuit: Vacuum Tube

Speaker Configuration

• Speaker Configuration: 1x12
• Number of Speakers: 1
• Speaker Diameter: 12"
• Speaker Manufacturer: Randall
• Speaker Model: RD1250-8
• Speaker Power Handling: 50W
• Speaker Grille: Heavy-Duty Steel
• External Speaker Connections: Yes

Front Panel Controls

• Clean Channel Gain: Dedicated Gain Control
• Overdrive Channel Gain: Dedicated Gain Control
• Overdrive Channel Volume: Dedicated Volume Control
• Channel Selector: Clean / Overdrive
• Tube Boost: Switchable
• Bass: Adjustable Low-Frequency Control
• Middle: Adjustable Midrange Control
• Treble: Adjustable High-Frequency Control
• Presence: Adjustable Upper-Frequency Response
• Master Volume: Global Amplifier Output Control
• Standby/Play Switch: Yes
• Power Switch: Yes

Audio Inputs

• Instrument Input: 1 x 1/4" Guitar Input
• Effects Return: 1 x 1/4" Jack
• Footswitch Input: 1 x 1/4" TRS Jack

Audio Outputs

• Speaker Outputs: 3 x 1/4" Speaker Jacks
• Single Speaker Output: Supports One 8-Ohm or 16-Ohm Cabinet
• Parallel Speaker Outputs: Supports One 4-Ohm Cabinet or Two 8-Ohm Cabinets
• Speaker Output Restriction: Single and Parallel Output Groups Must Not Be Used Simultaneously
• Direct Output: 1 x Balanced XLR
• Direct Output Processing: Speaker Cabinet Emulation
• Speaker Emulation: Miked Randall 4x12 Cabinet Simulation
• XLR Ground Lift: Yes
• Effects Send: 1 x 1/4" Jack

Effects Loop and Recording Features

• Effects Loop Type: Class A Discrete Instrument-Level Loop
• Effects Loop Connections: Send and Return
• Effects Return Function: External Preamplifier Input to Power Amplifier Section
• Effects Send Function: Unbalanced Preamplifier Output
• Direct Recording: Speaker-Emulated XLR Output
• Silent Recording: Supported with Master Volume at Zero and an Appropriate Speaker Load Connected
• Ground Loop Management: XLR Ground Lift Switch

Footswitch Specifications

• Footswitch Model: Randall RF2T2C
• Footswitch Type: Two-Button Controller
• Footswitch Functions: Channel Selection and Tube Boost
• Footswitch Connection: 1/4" TRS
• Footswitch Included: Yes

Power Specifications

• Power Source: AC Mains
• Power Connection: Rear-Panel AC Power Inlet
• Power Inlet Fuse: Integrated Fuse Holder
• Power Controls: Power and Standby/Play Switches

Physical Specifications

• Width: 22"
• Depth: 13"
• Height: 19"
• Weight: Approximately 58 lb
• Cabinet Type: Guitar Combo Amplifier Enclosure
• Exterior Color: Black
• Front Protection: Heavy-Duty Steel Speaker Grille

What's In the Box

• Randall RD20-112 Diavlo 20W 1x12 Tube Guitar Combo Amplifier
• Randall RF2T2C Two-Button Channel/Boost Footswitch