I flashed on how I run 7-volt Elrog ER50 direct-heated triodes on our Vinnie Rossi preamp's 5V setting. So Vivace owners can freely roll 88/120 GaNTubes for just sonics. From what I knew, it made Alberto's the first rollable transistor amps where instead of opamps, one swaps discrete output stages. Those who ridiculed the GaNTube concept for being shallow flash now had big black crow on the menu. Bon appetit. Of course keen observers remember Schiit's older LISSt, a solid-state plug-in tube replacement looking like a tube. They've also read of Brinkmann's BZ34 at right, a €600 tube simulator which can replace the 5AR4/GZ34 rectifier in their RöNt power supplies with transistors for unconditional stability and longevity so no valve aging. For seconds on Alberto's unique high-power solution, here's Dawid Grzyb's syndicated review of the standard Vivace with KT88; and his parallel review of Andante.

By August 13th, "the 120KT sounds spectacular and the extra power of 350 watts is definitely a big boost with low-efficiency speakers and/or large rooms. I hope to have final glass by September. If there are no issues in my supply chain, I should be able to send you Gran Vivace loaners during the second half of October." By December 6th, "Gran Vivace is ready. This is a 350-watt amp with 50A peak current which switches at ~768kHz. It has the same finesse as the smaller siblings but also the punch demanded by audiophiles who either have shamefully extreme, low-efficiency speakers or who are lucky to have huge listening rooms."

I neither had proper shame nor Mar-a-Lago size. My listening wouldn't exploit the raw grunt of the extra horses but report on sonics with 'normal' loads/rooms. Alberto's UK importer Greg Chapman of Val Hifi would provide the loaners. EU pricing for the standard finish Gran Vivace is €18'500/pr. The polished-chrome SE version gets €20'000. Vivace users wanting to run 120 outputs with its pair of 600V-rated GaN Mosfets will drop £3'000 for a pair. Rewiring the amps for higher power only carries the ship fees to California. My loaners were Gran Vivace wired for higher power. I can't tell you about sonic differences between a standard Vivace rolling either output stage. For that I'd need non-Gran Vivace and sets of both GaNTubes. That wasn't this assignment's brief. For that you'll want a different writer, publication and date.

More Gran Vivace specs are 70'000µF of reservoir capacitance, slew rate of 3'000V/µs, 125V peak-to-peak switching without over/undershoot, A-weighted output noise below 45µV, S/NR of -130dB, THD+N below 0.0075% (10W/1kHz), ~768kHz PWM switching at 94% efficiency and the low-pass output filter at ~86kHz. Over the original Vivace chassis, there's now a touch-sensitive standby switch on the top's front left corner and a 12V trigger port on the back. As before, it all fits into a 28x28cm square milled-from-solid chassis of 12.7cm height which weighs 10kg.

The steeper = quicker rising/falling edges of the Gallium Nitride (yellow line) vs. silicon Mosfet (magenta line) visualize the tech's higher speed when tasked to switch very rapidly without the 'rounding over' errors of traditional parts.

Delivery was by two hard-plastic flight cases locked with zip ties. Inside was precision-cut hard black foam for the amp recess, for a substantial red power cord then two bores for GanTubes which ship in protective bamboo sleeves. There was a nice cloth cover, then brochures plus owner's manual inside a substantial velcro-sealed fabric envelope. As the manual explains, during the 10-second turn-on, the main electrolytics charge up. The overall circuit has built-in fault detection plus fuses against over current whilst, for example, driving shorted outputs. A red LED on the back of the GanTube signals non-critical faults "neither caused by nor harmful to the amplifier" including over temperature, DC at the input, shorted terminals or extremely low-Ω loads. In such events one is asked to power the amp down to remedy the fault. A voltage selector with mains fuse integrates into the power switch. Changing its value also means changing the mains fuse, so a 2-2.5A slow-blow for 230V, a 4-5A for 115V. A 12V trigger on the rear can power up Gran Vivace remotely and a toggle not recommended to be switched under signal selects between RCA/XLR inputs. Being a power amp, there's no more to it than that. Flick the power mains on the back, tap the pressure-sensitive standby circle like a hen picks seeds. The light show starts. You're ready to go.