The Ceriatone Overtone Special HRM 100 is a hand-built valve amplifier inspired by one of the most sought-after American high-gain amplifier designs. The HRM (Hot Rubber Monkey) circuit incorporates an internal overdrive tone stack, allowing the overdrive channel's bass, middle, and treble response to be adjusted independently for precise gain shaping. Separate master volume controls for the clean and overdrive channels provide excellent control across a wide range of playing volumes, while the Preamp Boost delivers a more aggressive, saturated voice when engaged.
Like all Ceriatone amplifiers, the Overtone Special HRM is built with premium components and custom-designed transformers for exceptional reliability, dynamic response, and harmonic richness.
Specifications
Type: Valve Guitar Amplifier Head
Inputs: High and Low
Channels: Clean and Overdrive
Gain Control: Push-Pull Bright Switch
EQ: Shared Treble, Middle and Bass
Channel Switches: Mid-Boost, Deep, Rock/Jazz
Overdrive Controls: Drive, Level
Overdrive Tone Stack: Internal Adjustable Treble, Middle and Bass Trimmers (HRM)
Master Volumes: Independent for Each Channel
Rear Panel Control: OD Trim
Effects Loop: Passive
Power Modes: Full/Half Power
Footswitch: Channel Select and Preamp Boost
Power Valves: 4 × 6L6GC
Preamp Valves: 3 × 12AX7 / ECC83
Rectifier: Solid State
Transformers: Custom Ceriatone
This example has been extensively upgraded by Australian amp builder Shaun Klinger. Originally a 50-watt amplifier, it has been professionally converted to 100 watts and fitted with a custom faceplate that adds dedicated controls for overdrive channel boost and low-end response, providing greater tonal flexibility than the standard specification. It has also been fitted with a new set of valves.
Includes the original footswitch and a fitted vinyl cover.
