The THD UniValve 15W Class A Amplifier Head delivers tones from smooth and clear to warm and full to aggressive overdrive. The single-ended Class A circuit design uses the highest-quality parts and hand-built construction for clean and faultless operation.
The single output tube can be switched at will with nearly any octal-based power tube for different tones without re-biasing the amp, and the 2 preamp tubes can be switched for any combination of 12AX7, 12AT7, 12AU7, 12AY7, or 12AZ7 tubes.
The UniValve is easily capable of driving a 4×12″ cabinet, yet is also small and light. Its built-in Hot Plate Power Attenuator lets you experience the indescribable freedom of wailing away with full output distortion at volume levels that are quiet enough to let your neighbors sleep.
There are 2 inputs—one for high gain and one for low gain. With 12AX7 preamp tubes, the low gain input gives a wide range of sounds from Nashville clean and crisp to Memphis down and dirty. With the controls pegged and a relatively high-output humbucker, the low-gain input delivers a tantalizing Texas blues overdrive. Plug into the high-gain input for a whole new world—from early British Invasion tones to modern high-gain metal attack—but with none of the mush and confusion normally associated with high-gain tones.
The controls include the traditional Volume, Treble, and Bass along with an Attitude control knob that determines how the driver stage responds to signal and how it drives the power tube. There are also controls for the Hot Plate, including a hard-bypass switch. The noise reduction circuit in the Hot Plate features a light bulb fixture on the front panel that glows when you play. There is an On-Off switch for the light bulb.
On the back panel the UniValve has a transformer-isolated line out with an adjustable level control and a switch to choose line-level or instrument-level signal. The speaker outs on the UniValve can drive any speaker load from 2 ohms all the way up to 16 ohms. When there is no speaker plugged into the speaker jack, the amp uses its own built-in dummy load so no damage will occur, so it’s also mighty good for direct recording.
- 15W Class A amplifier
- Single-ended Class A circuit
- Accepts almost any power tubes in any combination
- Ships with 2 – 12AX7s (preamp) and a single EL34 (power amp)
- 2 preamp tubes can be any combination of 12AX7, 12AT7, 12AU7, 12AY7, or 12AZ7 tubes
- 2 inputs: one for high gain and one for low gain
- Volume, Treble, Bass, and Attitude knobs
- Built-in Hot Plate output attenuator
- Volume, Treble, and Bass controls
- Attitude control knob
- Hard-bypass switch for Hot Plate
- Light bulb noise-reduction circuit
- On-Off switch for light bulb circuit
- Transformer-isolated line out with adjustable level control
- Choose Line-Level or Instrument-Level signal
- 2 ohms to 16 ohms speaker load
- Built-in dummy load
This amp has been used lightly, and only ever at home or in a studio. The only change from original is the Attenuation knob, which went missing a while ago. Apart from that it is as original as new, and ready to rock for years to come.
This is an amplifier born to produce every sound you’ve ever wanted, and some you haven’t thought of yet – with the highest tonal quality. Tube-swap your way to a whole new tonal territory.