DHA ValveTone VT1 Mk3 Hi-Plate Bass


  • Level
    sets the output level of the effect to your amplifier, there is a fair amount of gain generated by the valve and op-amp and this will overdrive the input of your guitar amplifier.
  • Gain
    sets the level into the second stage of the valve and hence the level of gain. Use your volume control on your guitar to control the gain on the first stage of the valve, you will find that the ValveTone 1 Hi-Plate Bass responses very well to this and you can control the break-up distortion like this.
  • Clip (switch)
    is neat trick you won’t have seen before on this type of effect. In the centre position (None) there is no clipping selected and the only clipping heard at higher gains is the valve soft chipping. The Si position connects two Silicon diodes across signal path to produce a harder Fuzz type clipping. The Ge position switches in 4 Germanium diodes, this is a much softer clipping, please note because the Germanium diodes reverse voltage is much lower than Silicon the volume we drop. There is an op-amp in the pedal which boosts the output level, the amount of clean volume can be adjusted using the pre-set pot which can be found inside box on the veroboard.


the manual

The ValveTone 1 Hi-Plate Bass uses a single 12AX7 (ECC83) valve to generate classic pure valve tones. There are two modes of operation, overdrive and clipping distortion which also has 2 separate options of clipping. The ValveTone 1 Hi-Plate Bass is a low to medium gain effect and is intended to be used in front of a valve amplifier, but will also work well with solid state amps. The foot switch provides a true by-pass.

The ValveTone 1 Hi-Plate Bass is fitted with 2.1mm external PSU adaptor for use with a 12v @ 1200mA external supply. The user should use a well regulated external supply as the better the regulation then the less the hum when at higher gain levels. The inner of the connector is the positive, there is reverse polarity protection so no harm will be done if you get it wrong. There is a voltage doubler circuit inside the pedal which generates the 24V anode or plate voltage for the valve.

Dave Hall Amps (DHA) (2008)

The VT1 MK3 Bass from DHA is a hand built valve Overdrive and Distortion effects pedal which uses a 12AX7 (ECC83) preamp valve to provide true valve tone, the tone generated has to be heard to be believed!

The VT1 MK3 Bass is suited to guitarists looking for overdrive valve tone for blues and rock.

This new model also has the selectable "Colour" control for added gain, distortion and compression.

The Valve is visible and there is a cool blue led backlight which doubles up as the power on indicator.

It has two main modes of operation, Overdrive Distortion and Clipping (Fuzz) Distortion. Overdrive is achieved by using both gain stages in the 12AX7 valve to generate the classic valve pre-amp overdrive tone plus a clean op-amp for extra output volume.

The valve is ran at 24V DC so valve soft clipping is generated at low levels of gain and this is amplified by the valve's second stage and the selectable op-amp to provide lots of overdrive volume. This is great with modern solid state amps and fantastic with valve amps.

The VT1 MK3 Bass will even sound great when plugged directly into a desk or a digital recording setup.

There are three selectable types of Distortion.

  1. Valve overdrive - Classic preamp overdrive, Overdrive mode.
  2. Silicon Diode Clipping - Hard Clipping Fuzz.
  3. Germanium Diode Clipping - Soft Clipping Fuzz.

The two selectable types of Colour control add to the tone selection giving the VT1 MK3 Bass a very wide range of tones possible.

The Gain and Level controls let you select that tone you been looking for! And don't forget the volume and tone on your guitar which will react well with the VT1 MK3 Bass just like a real valve amp.

There is a true By-Pass Foot Switch and a LED effect on indicator.

The VT1 MK3 Bass has a new feature not seen before, this is called Colour. There are 3 settings selectable with the Colour switch they are off, 1 or 2. There is also a Colour pot which adjust the amount when 1 or 2 is selected. Colour increases the compression and gain.

The tone is prue valve, fat and warm and completely different to silicon effects pedals which tend to fizz and compress the signal. Unlike silicon pedals you can use the volume control on your guitar to control the amount of distortion you want, just turn it up for the lead solo.

Think SVR's Little Wing, BB King or even Angus on any AC/DC track!

There is a selectable boost function with a boost level control. This adds additional clean output volume to the valve signal using a low noise op-amp. This function is very usefull when very low levels of gain are required for clean but fat valve tones. The boost switch allows the user to true by-pass this function so giving a true valve path.

There is also an i/p pad control which allows you to set the drive level into the pedal. This is very useful when using high output pickups and active basses.

TheVT1 MK3 Bass runs from a 9-12V DC 1200mA supply via a standard 2.1mm socket, there is an internal switch mode power supply which generates the the 24V Plate voltage.

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