Blackstar's HT range all feature a valve in the circuitry, allowing you to dial in a certain amount of saturation to the sound.
"You'll get an easy-to-dial-in range of modulations, with the bonus of added valve warmth"
There's a choice of eight modulation effects, each with adjustable speed, plus feedback and level knobs that, if not controlling feedback or level, have a function dependent on the effect, such as modulation depth for a chorus or waveform shape for a tremolo.
It also gives you the ability to change the speed from slow to fast with a second footswitch.
If you don't mind an extra power supply on your 'board, you'll get an easy-to-dial-in range of modulations, with the bonus of added valve warmth.