Cavalli Audio Liquid Fire Headphone Amp (Playback 45)

State of the Art

Cavalli Audio is a well-respected producer of DIY headphone amplifier designs. As is often the case, these designs are the product of a particular and dedicated person, in this case Dr. Alex Cavalli. Cavalli has decided to move beyond the DIY market with the introduction of the Liquid Fire amplifier, which a fully finished (not kit-built) high-end amp available directly from Cavalli or from certain dealers.

FEATURES

The Cavalli Liquid Fire is a hybrid headphone amp, meaning that it uses a combination of tube- and solid-state-powered output circuitry. While hybrid circuits are not new, there are several aspects of the Liquid Fire design that are distinctive, as we have reported previously:

• First, the Liquid Fire uses an entirely DC coupled hybrid circuit, meaning that there are no capacitors in the signal path at all.
  
•  All voltage amplification is handled purely by tubes, where the tube complement includes four JJ Tesla 6922 tubes—each of which has burned-in for 25 hours prior to shipment of the amp.
• The tube section of the amplifier is fed by its own dedicated dual (+/-) 100V power supply.
• A 20-second tube heater delay circuit (with color-coded LED indicator lights) ensures that tube warm-up is complete before the tube circuit is fully engaged.
• A combination of conventional and MOSFET transistors handles all power output amplification. (The MOSFET output stage is biased at 100mA and runs in Class A almost all of the time.).
• The solid-state section of the amplifier is fed by a separate, dedicated dual (+/-) 30V power supply.
• An opamp servo circuit ensures that DC offset is held at 0VDC.
• A 20-second output delay/DC offset detection circuit (again with color coded indicator lights) ensures that power output circuitry is properly warmed up, and DC offset is properly set at 0VDC, before the headphone output jacks are enabled.
•  Key amplifier components (chassis enclosure, RCore transformer, piezo-electric power switch) are U.S. made.
  

In a move that I consider near-genius, Cavalli offers the amp with two headphone jacks, one providing 1/4 ohm output impedance and the other sporting your choice of 1/4, 50 or 100 ohm output impedance.

The amp strives to provide a best-of-two-world’s design, combining the transparency, harmonic richness, and sonic liquidity of great tube circuits with the cleanliness, precision, and control of great solid-state circuits.

The design reflects this approach. Some tube amps cultivate a deliberately retro, son-of-1950’s-vintage-McIntosh-amps vibe, but the Cavalli Liquid Fire sports a distinctly modern design. The moderately sized amp is housed in a matte black enclosure that sports two front panel tube viewing windows, upon which is imprinted Cavalli’s signature “yin/yang” logo. If you look closely, one side of the yin/yang panel features the schematic symbol for a vacuum tube, while the other features the symbol for a transistor. The Yin/Yang theme is repeated in the top cover ventilation scheme.

Balancing all those goals is a tall order, though Chris Martens’ First Listen article suggested good things ahead. In any event, I was anxious to see how well Cavalli succeeded.

SONIC CHARACTER

The Liquid Fire is one of those extremely good amps that is hard to review because it really doesn’t contribute any obvious or readily identifiable sonic “flavorings” to the music at all, which is a good thing. If you think about it, you’ll realize that in some sense the perfect amplifier would have no sound of its own—it would simply get out of the way and let the music through. The Cavalli more closely fits that ideal no-sound-of-its-own paradigm than other amplifiers I have reviewed, though the Woo WA22 has a similar “issue” (i.e., offers similar sonic neutrality).

Still, it isn’t very interesting or helpful to just stop the review here, leaving the reader with the obvious implication to run out and buy this amp. Anyway, the Cavalli doesn’t sound like the Woo, so obviously there is something more to say. And, despite its sonic righteousness, I don’t think the Liquid Fire is the amp for everyone. More on that anon.