Blackstar HT-20R MKIII 20W Valve Guitar Amplifier Head

While the traditional method of crafting amplifiers involves starting with a preamp design and attaching it to a range of power amplifiers with varying power ratings, Blackstar's HT-20R MKIII 20W Valve Guitar Amplifier Head takes a unique approach. Recognizing the interaction between preamp and power amp, Blackstar ensures that each model receives individual care and attention during sonic testing, with necessary tweaks made to the circuitry to meet high tonal expectations.

The MK III Clean channel is a sophisticated circuit that, despite its simple appearance, is highly versatile in producing a range of classic clean and crunch tones. Utilizing both parts of an ECC83 valve, it can produce valve compression or crunch, depending on your needs.

The HT MK III overdrive channels are a progression from Series One, HT MkI to HT Venue MK III. They share the same basic building blocks in the gain structure and tonal shaping, including the cascaded gain stages of an ECC83 double triode valve. Each amp's overdrive tones have been specifically tweaked and refined during extensive listening tests to optimize the tone for that model.

One of the key features of the Overdrive channels is how well the tone cleans up when the guitar volume is reduced. This is primarily due to the way the signal is filtered or 'shaped' after the valve is overdriven. Unlike conventional valve amp designs, the HT MK III Overdrive channels use a second order low pass filter to remove high frequency 'fizz' without attenuating the signal below the cut-off frequency. This ensures that when the guitar volume is reduced, the remaining clean sound is still full and dynamic.

The HT-20R MKIII also features Blackstar's patented Infinite Shape Feature (ISF), which allows you to infinitely adjust the response of the tone control network between any of the traditional voicings. This innovative feature lets you design your own sound and find 'the sound in your head'.

The amplifier also boasts Voice switches, which allow you to tailor the tone of the amp further. These switches can be footswitched for ultimate flexibility during live performances. The Clean Channel offers two distinct settings based on classic American clean sound and vintage 'Class A' British tone, while the Overdrive Channel allows you to switch between a classic tone and a higher gain, more contemporary tone.

The HT-20R MKIII also features Blackstar's proprietary digital reverbs, which have been voiced to work well with both clean and overdriven tones. These exclusive designs respond well to both the dynamic nature of clean sounds and the more compressed, harmonic rich textures of crunch and high gain overdrive sounds.

The CabRig 3-way switch allows you to switch between the three currently stored CabRig settings, with almost unlimited further options controlled and set in the Architect software app. CabRig is Blackstar's next-generation IR-based DSP speaker simulator, which reproduces the rich, dynamic characteristics of real-world guitar cabs.

The HT MK III amplifier also features improved XLR and Headphone / Line Outputs, a new USB-C connection for USB audio connection and connection to a computer to run Blackstar's proprietary Architect software, and a standard latching 2-way footswitch for easy switching between the two Clean channel voices and two Overdrive voices.

As with all Blackstar products, the HT MK III amplifiers are designed for maximum reliability, with all power dissipating components de-rated by at least 100%. All the amplifiers are thoroughly endurance tested on custom built automatic test equipment to replicate many hours of real life use in a few days of laboratory testing. The HT MK III amplifiers also make the power amplifier 'safe' in the event of certain hazardous conditions, by biasing the power valves out of conduction and muting the input to the power valves.