THD UniValve is a Single-Ended Class A amplifier head with a single output tube that can be switched at will among many octal-based power tubes for different tones without re-biasing the amp. Useable tubes include 6L6, EL34, 6550, KT90, KT88, KT77 and KT66. With the amp in “LoV” setting you can use 6V6 for a total output of 5 watts. A special UniValve Yellow Jacket™ Converter is available allowing the UniValve to use the popular EL84 power tube at a total of 4 watts output power, also in “LoV” setting. Likewise, the two preamp tubes can be any combination of 12AX7, 12AT7, 12AU7, 12AY7 or 12AZ7
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, and its also awesome for direct recording.