The Blackstar HT-Dual is a tube-powered distortion, overdrive and preamp pedal from the UK maker's HT series of "pure valve distortion" pedals. It carries a twin valve preamp built on two cascaded ECC83 (12AX7) triode stages for gain, run at appropriate amp voltages, around 300V, instead of being starved, and it offers two footswitchable channels. Because channel 1 also hides an additional clean/crunch option that is not footswitchable, Premier Guitar's reviewer described it as effectively a 3-channel preamp1.
How it works and what it does to your sound
The core idea of the HT series is that a tube-powered distortion/overdrive/preamp pedal is not new, but running two cascaded triode stages at proper amp voltages is Blackstar's twist on it. The result, per Premier Guitar's review, is overdrive channels with "really great grind, and rich, 'tubey' harmonic distortion," though the reviewer noted they lack the glassy-smooth compression and bark of a tube amp's overdrive channels1.
With the ISF set to the UK side, the reviewer found channel 1 produced an outstanding Marshall-like sound with crisp top end, woody mids, and tight crunch, while channel 2 had much more gain but retained the harmonic subtlety and nuance of a dimed Vox on the UK voicing1.
Channels at a glance
| Channel | Voicing | What the reviewer found |
|---|---|---|
| Channel 1 | Clean/crunch option (not footswitchable) plus drive | An outstanding Marshall-like sound on the UK setting: crisp top end, woody mids, tight crunch1 |
| Channel 2 | Higher-gain drive | Much more gain, but retained the harmonic subtlety and nuance of a dimed Vox on the UK voicing1 |
Because the clean/crunch option on channel 1 cannot be switched by foot, the pedal works in practice like a three-voicing preamp with two footswitchable channels1.
The ISF control
The pedal's signature control is Blackstar's patent-applied-for "Infinite Shape Feature," or ISF, a tone contour that expresses voicings as the distance between classic American and British voicings1.
- Fully clockwise (CW): the UK side of the voicing sweep1
- Fully counter-clockwise (CCW): the US side of the voicing sweep1
The reviewer's verdict was blunt: "The UK side of the control knob (turned fully CW) is much more genuinely convincing than the US side (fully CCW)"1.
Recording and outputs
Like the other members of the HT series, the Dual provides an additional speaker emulated output, so you can go directly into a DAW without miking a cabinet1. That makes it usable as a recording preamp as well as a front-of-amp drive.
Power and bypass
The HT-Dual needs a 16V AC supply, not the 9V DC center-negative standard most pedalboard power supplies deliver. Plan a dedicated supply output for it.
The pedal uses silent switching and a High Integrity buffered bypass rather than true bypass1.
Build
Physically, Premier Guitar called the HT-Dual a top quality unit: nice looking, sturdy, and substantial, with an orange glow from the valve window, which is really an LED1.
For a wider view of the category, see Distortion Pedals.
Videos
ProGuitarShopDemos
Coleman's Music
Robert Baker
Questions
Does the Blackstar HT-Dual have real tubes in it?
Yes. The HT-Dual is a tube-powered hybrid design with a twin valve preamp built around two cascaded ECC83 (12AX7) triode stages for gain. Premier Guitar's review notes that Blackstar runs the tubes at appropriate amp voltages, around 300V, rather than starving them, which is the design idea behind the whole HT series of valve distortion pedals.
What power supply does the HT-Dual need?
The HT-Dual requires a 16V AC power supply. That is an unusual requirement compared with standard 9V DC pedals, so it rules out sharing a typical pedalboard daisy chain and means you need to plan for its own supply if it is in your signal chain.
What does the ISF knob do?
ISF stands for Infinite Shape Feature, a patent-applied-for tone contour that sweeps between classic American and British voicings. Turned fully clockwise you get the UK side, fully counter-clockwise the US side. Premier Guitar's reviewer found the UK side much more genuinely convincing than the US side.
Can I plug the HT-Dual straight into a DAW?
Yes. Like the other members of the HT series, the Dual provides an additional speaker emulated output, so you can go directly into an audio interface or DAW without a microphone or a speaker cabinet.
Is the HT-Dual true bypass?
No. The HT-Dual features silent switching and a High Integrity buffered bypass rather than true bypass. A buffered bypass can be useful on larger boards with long cable runs, though players who prefer a strictly unbuffered signal path should know it is not true bypass.
How much did the HT-Dual cost?
The HT-Dual carried an MSRP of $299 USD, according to Premier Guitar's review.
Sources (1)
- Review: Blackstar HT-Dual Distortion, Premier Guitar, 2008-08-18
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