THD UniValve Class-A 15-Watt Tube Guitar Amp Head – USA 2008

by THD

$1,095.00 20085

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, including 6L6, 6CA7, 6V6, EL34, KT88 and many more – magnify our pics & you’ll see the list stamped on the amp chassis.

The 2 preamp tubes can also be switched for any combination of 12AX7, 12AT7, 12AU7, 12AY7, or 12AZ7 tubes.

The UniValve is easily capable of driving a 4x12" 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 neighbour’s 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 it's also mighty good for direct recording.


  • 15W Class A amplifier
  • Single-ended Class A circuit
  • Hand built
  • 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. Its 110 volt transformer was replaced with a genuine THD brand 240v unit by respected Sydney amp tech Dave Peach. Apart from that, there are no changes or modifications, and it presents 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.

Comes with its owner’s manual and dozens of various tubes including all


If you would like to know more about an item or buy it, please click on "I'm interested" on the product page or call John on 0414 994 506


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