The music sounds so good on The Woo Audio WA7 Fireflies that you are going to listen louder than its usual for you. The acoustic tunes have the warmth that reminds of live music. The WA7 Fireflies with little amp sounds so powerful and the sound never grew strained or harsh.
The 5-inch cube headphone amplifier has two vacuum tubes protected by a thick glass cover. It has a built-in 32-bit/192kHz USB digital-to-analog converter (DAC) and lots of custom-made parts, including dedicated nickel alloy output transformers. There’s a 6.3mm jack for home-style headphones, and a 3.5mm jack for portable ones. That’s noteworthy, as few headphone amps have both jack sizes. The silky feeling volume control, the solid aluminum chassis, and the thick glass top cover all impart a quality feel. An impedance switch on the rear panel allows the user to optimize the WA7′s sound for low (under 70 ohm) or high impedance (over 70 ohm) headphones.
Stereo RCA analog inputs are also provided so you can listen to external sources, such as a radio or a higher-quality DAC like my Schiit Bifrost. The WA7′s separate, 2.8 pound AC power supply is larger than the amp! The WA7 is available in silver or black finishes for $799 through Monday, January 28, after that date the price goes up to $999. If you compare the WA7′s sound with solid-state Burson Audio HA-160 amp, which had a leaner and cooler tonal balance, and with bright sounding headphones like the Sennheiser HD 700 or Grado RS-1, you will be more satisfied with the WA7.
The Woo Audio WA7 Fireflies is sold direct from the company with a 20-day return guarantee, but there is a 10 percent restocking fee.