The R&R SL/LD MultiGain PRE-AMPLIFIER is a 3-channel guitar preamp designed with five 12AX7 tubes, featuring a 1U rack design for versatile use in both studio and live concert settings. It offers a wide range of sound adjustments, allowing users to achieve their unique desired tone.

Function Description

The preamp features an all-tube sound path utilizing five 12AX7 tubes, with the flexibility to use tubes from different manufacturers for clean and overdrive sounds. It boasts three completely independent channels:

CH-1 CLEAN (clean channel): This channel's "GAIN" control is central to its sound. Low GAIN values are ideal for playing picks and drumming rhythms, while high values produce a "glassy," crystal-clear, and transparent sound suitable for blues solos. With powerful humbuckers and GAIN set near maximum, a slight crunch can be achieved. Excellent channel dynamics allow for solo emphasis through increased attack. A 3-band pre-gain EQ provides fine-tuning capabilities.
CH-2 LEAD-1 (overdrive channel): This channel significantly overloads the sound, making it suitable for blues, hard rock, and heavy metal from the 70s and 80s, as well as other styles not requiring high-gain overdrive. It delivers a transparent, warm, overtone-rich sound, where harmonics "shoot" from under the fingers even at low GAIN levels. The "BRIGHT" switch adds "glass" to solos and sharpens rhythms. A 3-band post-gain EQ and a "PRESENCE" control enable a wide palette of sounds.
CH-3 LEAD-2 (drive channel): This channel offers a very dense, aggressive, heavy, and fat HI-GAIN overdrive, characteristic of "Californian" sound. It provides incredible gain, excellent tube warmth, and compression. The sound is highly versatile, suitable for both Gary Moore's stringy solos and the tight rhythm of the heaviest styles, with good readability in low tunings. A 3-band EQ is located after the gain, and the "PRESENCE" control helps your part stand out in the mix.

Channel switching can be performed both from the front panel and via the included 2-button foot controller.

The device includes an FX LOOP tube effects loop with selectable operating modes (serial or parallel). This loop can be switched on/off separately for clean/drive channels and controlled from a two-button foot controller. It helps soften the sound of transistor and digital processing by incorporating a 12AX7 lamp in the circuit.

For channel CH-3 (LEAD-2), the A250K / A1M mode GAIN control offers two distinct sound characteristics: A250K provides a more punchy sound with pronounced low frequencies, while A1M delivers balanced high and low frequencies.

The preamp can be connected to the instrument input of a guitar amplifier (functioning as an effects pedal), to the RETURN of a guitar amplifier, or directly to a final power amplifier (as a preamp). It also features a built-in speaker simulator for line connection and recording devices, along with a dedicated headphone output.

Important Technical Specifications

Input impedance: 1 megaohm
Output impedance: 25 kiloohm (at maximum output signal level)
Power consumption: 40 Watts
Mass: 4.3 kg
Height: 1U (one rack space)
Depth: 180 mm
Tubes: Five 12AX7 tubes (V1: Channel input CH-1 CLEAN; V2: Channel input CH-2 LEAD-1 and CH-3 LEAD-2; V3, V4: Channels CH-2 LEAD-1 and CH-3 LEAD-2; V5: FX LOOP)
Power Supply: 110V or 230V AC (selectable)

Usage Features

Front Panel Controls:

POWER ROUND/OFF/EDGE: Selects between "ROUND" (more viscous, compressed sound), "OFF" (turned off), and "EDGE" (sharper sound) modes.
POWER LED: Red glow indicator for power.
MASTER: Controls the overall output level for all three channels.
CH-1 CLEAN (CLEAN CH-1):
- INPUT: Instrument input for guitar.
- GAIN: Controls overall gain and sensitivity.
- TREBLE, MID, BASS: 3-band EQ for high, mid, and low frequencies.
- CLEAN LED: Green indicator for CH-1 activity.
- CLEAN / LEAD: Selects between CLEAN (CH-1) and LEAD (CH-2/CH-3) channels.
CH-2 LEAD-1 and CH-3 LEAD-2 (LEAD CH-2 and CH-3):
- GAIN: Controls overall gain and sensitivity for CH-2 and CH-3.
- TREBLE, MID, BASS: 3-band EQ for high, mid, and low frequencies.
- PRESENCE: Transparency control for higher frequencies than the TREBLE control.
- MASTER: Master volume for CH-2 and CH-3.
- LEAD-1 / LEAD-2 (CH-2/CH-3): Selects between CH-2 and CH-3.
- "LEAD-1" LED: Blue indicator for CH-2 activity.
- "LEAD-2" LED: Red indicator for CH-3 activity.

Back Panel Controls:

AC 110V or 230V: Power connection.
PHONES: Headphone output.
POWER AMP: Output for connecting to a power amplifier input.
LINE OUT: Output for connecting to an instrument output or FX RETURN loop of a combo amp, designed for more sensitive outputs than POWER AMP.
REC OUT: Output from the speaker simulator for connecting to a mixer, recording devices, or computer sound card, designed for recording with stack sound emulation.
INPUT: Instrument input for guitar.
FX LOOP:
- SERIAL / PARALLEL: Switches between serial and parallel FX LOOP modes.
- MIX: Controls the amount of processed signal in the FX LOOP relative to the unprocessed signal.
- SEND | RETURN: Controls the level of the signal sent to and returned from the FX LOOP.
- LEAD | CLEAN ON/OFF: Turns the effects loop on/off for LEAD channels (CH-2, CH-3) and CLEAN channel (CH-1).
- FX SEND | FX RETURN: Jacks for connecting external effects.
A250K / A1M: Controls the GAIN knob for CH-3 LEAD-2, switching between A250K (punchy, pronounced lows) and A1M (balanced highs and lows).
CH-2 BRIGHT / CH-2 NORMAL: Switches between BRIGHT (adds brightness) and NORMAL modes for CH-2 LEAD-1.
FSW CH-1, CH-2, CH-3 | FSW LOOP: Selects channel activity (CLEAN, LEAD-1, LEAD-2) and controls FX LOOP on/off with external 2-button foot controllers.

Maintenance Features

Qualified Personnel: Only qualified personnel should repair the appliance.
Operation Guidelines: Operate the instrument strictly according to the instructions and recommendations in the manual.
Environmental Conditions: Do not store or operate in high humidity, direct sunlight, or near heating devices.
Grounding: Ensure reliable grounding.
Power Connection: Verify that the mains voltage matches the device's power supply requirements (indicated on the nameplate or cover).
Emergency Disconnect: Unplug the power cord in case of fire.
Cable Reconnection: Reconnect cables only when the equipment is turned off.
Switch and Control Handling: Do not use excessive force when operating switches and controls.
Hot Lamps: Avoid touching heated lamps.
Lamp Replacement:
- Turn off the device before replacing lamps.
- Remove cooled lamps from the base by gently rocking in different directions.
- Install only serviceable lamps of the appropriate type into their respective sockets.
Cleaning: Use a clean, dry cloth to clean the instrument body; do not use solvents.
Long-Term Storage: Disconnect the device from the mains if it will not be used for an extended period.
Input Usage: Only one input (INPUT FRONT or INPUT BACK) should be used at a time.

R&R Ampflication SL - Channel Setting CH-3 LEAD-2

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