As per this graph, Andante's ~140dB noise floor exhibits low 2nd and 3rd-order harmonic distortion. Any higher-order product moves -145dB down. This gives Alberto's class D amplifiers ideal operation conditions to show off their high detail magnification.

Here we see the amplifier's own distortion behavior [left XLR driven, right RCA driven]…

… and a Vivace view from my review which detailed its tech. Rewired at the US factory to Gran Vivace, it'd return looking identical except for a thicker GaNTube rising from the asymmetrical back-lit plexi hood. In January 2020, Alberto had aimed his bigger tube for 150/300w into 8/4Ω but thought that up to 360 watts were possible. He'd know once first 4-layer dual circuit boards for the 120 arrived to measure their distortion behavior under peak power and lock them into their sweet spot.

By May 16th 2020, "I'm glad to inform you that I expect final parts for the bigger GaNTube next month and should have a definitive date soon. For now, two views on the new tube to show its proportions relative to the one you're familiar with."

KT120, KT88 and EL34-type glass bulbs without PCB | 120 GaNTube with PCB and socket.

Would Gran Vivace adopt the 120 exclusively to reserve the 88 for the smaller Audion? Would Vivace remain available in two versions? "I think I'll keep both. Sound and power differentiate them. Clients decide what's best for their system, taste and music. The 150 can plug into the standard Vivace to run on lower voltage. That won't do anything detrimental to its sound quality. Gran's power supply is identical, just calibrated for higher voltage. So the comparison will be fair. If one categorically prefers the 150 and wants higher power, one can opt for the modification. Its target remains 350 watts into 4Ω [so 75% up from the 200 watts of the standard version – Ed.]."