Cavalli Audio is a USA-based manufacturer of world-class headphone amplifiers. They are ‘bespoke’ products, since the amps typically allow at least some degree of customization to meet buyers’ requirements. But the underlying qualities that typify all Cavalli designs involve company founder Dr. Alex Cavalli’s commitment to sound quality and to the sort of rigourous and conservative engineering that makes for long-term reliability. Where some designers proudly tout ‘edge of the envelope designs’, Dr. Cavalli rejects the idea of pushing circuit parameters ‘to the edge’ as ill-advised posturing at best and shoddy engineering at the worst. As Dr. Cavalli once said to Hi-Fi+, “if you have to use ultra-exotic parts or stress your circuitry to the limits to get the performance you need, then you probably do not have an adequate design in the first place.”
Cavalli’s first two headphone amplifiers, the Liquid Fire, an amplifier geared for use with conventional (that is, dynamic or planar magnetic driver-equipped) headphones, and the Liquid Lightning, geared specifically for use with electrostatic headphones, have both received considerable critical acclaim (some writers consider the Liquid Fire and Liquid Lightning as true, state-of-the-art designs). But now Cavalli’s third amplifier, called the Liquid Glass ($3,500 in the US, or £2,325 in the UK), has entered production.
Before we start, it might be useful to talk about the nature of the sound Cavalli is pursuing. Cavalli Audio, I would say, does its level best to pursue tonal neutrality, high levels of resolution, and extreme faithfulness to the incoming audio signal. But unlike some competing accuracy-seeking amps, which can at times sound sterile and antiseptic, Cavalli amplifiers strive to capture the unforced, “liquid” character of live music itself, which is why Dr. Cavalli often uses the word “Liquid” in his amplifier names.
Cavalli’s Liquid Glass amplifier, however, offers a fresh take on the case for a ‘neutrality-über-alles’ sound, in that it is a hybrid valve/solid-state amplifier created specifically for those known as ‘tube rollers’ (that is, enthusiasts who experiment with various valve substitutions in search of ever higher levels of sound quality). As Cavalli says, the Liquid Glass “is especially designed to reflect exactly what the tube [valve] does and sounds like.” Accordingly, the Liquid Glass provides a tube-powered front-end section backed by a high-input-impedance (and thus easy-to-drive), ultra high-resolution, ultra-low-noise solid-state output buffer section. In the interest of even greater sonic purity, Cavalli notes that, “there is intentionally no global negative feedback, which is normally used [in other manufacturer’s designs] to reduce THD and increase bandwidth.” But, as the amplifier’s specifications demonstrate, the Liquid Glass delivers exemplary bandwidth and low distortion, even without global negative feedback.
Moreover, the tube section is extremely versatile, providing pairs of both octal (that is, eight-pin) and nonal (that is, nine-pin) valve sockets, with separate user selectable controls for setting valve heater and plate voltages. For my tests I tried sets of 6SN7, 6GU7, 12AU7, CV181, 8416, and 6922 valves, but there are many more types of valves the Liquid Glass can support (see Technical Specifications, below, for a complete list). As a general rule, if a desired valve type fits the Cavalli’s valve sockets (and, Dr. Cavalli advises, “conforms to either 6SN7 or 12AU7 pin-out arrangements…”), then the valve can be made to work in the Liquid Glass. The point is that users can choose from amongst hundreds of types and brands of valves, each offering their own distinctive take on the sonic truth.