This is a mono-block amplifier which is meant to be paired with open baffle speakers. The damping factor is such that the speaker helps the amplifier produce holographic sound effects with open baffle speakers. Not all tube amplifiers and other types of amplifiers do this, this is unique to some single ended tube amplifiers, and this amplifier is made to exploit that one aspect of the speaker amplifier interaction. I refer to this interaction as a dance between the amplifier and the speaker.  Similar to actual ballroom dance partners, one leads and the other follows, such that you have a synchronous unity as they act as one to produce a sound.

We designed the UA2.5v2 to be paired with the HPA2.1, and HPA2.3(unreleased) so that the UA2.5v2 will function as a headphone amplifier and pre-amplifier for these mono-blocks. We were going to release a pre-amplifier specifically designed for these mono-blocks but the versatility and benefits of the pairing could not be ignored. This also makes it so that if you currently have a UA2.5 you can upgrade to a pair of UA2.5m (Mono-blocks) and use your existing UA2.5 as a pre-amplifier. The pentode upon pentode effect is exasperated such that the dynamics of the integrated coupled with the mono-blocks produces dynamics not previously heard from pentode amplification.