For my taste, the Woo Audio WA7tp Fireflies headphone amplifier is the best looking component of this century. I mean that, pictures don't do it full justice. The metal and glass design on my desktop is a sight to behold, and I thought so when I reviewed the original WA7 in 2013, the updated model I'm reviewing here today debuted in March 2016. If anything, I have only come to admire the design even more.
Of course, it also has to sound good to be worth reviewing here on the Audiophiliac, and the WA7tp's sound is pretty darn special. The amp has a built-in ultra-high resolution 384 kHz/24-bit USB digital converter. The WA7tp is a "two-box" design, as shown in these images, the left component is the vacuum tube power supply, and the right component is the tube headphone amplifier. The amp and matching tube power supply are small, 5-inch (127mm) cubes, they're available in silver or black finishes.
The amp features custom-made nickel alloy core output transformers, and an all-aluminum chassis with no screws visible from any viewing angles. The amp's rear panel hosts USB and analog stereo RCA inputs, but when you use the internal digital converter the RCA connectors are analog output jacks. Like all Woo products, the WA7tp is hand-crafted in New York City.
The WA7tp has two headphone jacks, a 6.3mm and a 3.5mm one. I used the 3.5mm jack with a couple of in-ear headphones, namely a set of Beyerdynamic iDX 200 iEs and my Ultimate Ears Reference Monitors. Most tube amps are too noisy to use with in-ear headphones, but the WA7tp was super-quiet, so it could clearly delineate the palpable textures on electronic music, like Brian Eno's recent album "The Ship."
I next pulled out my Audeze LCD 2 and Hifiman Edition X over-the-ear headphones. The WA7tp ever so gently embellished and sweetened the sound of music. What I'm saying is the WA7tp adds richness and warmth to the sound, but it never overtly softens or muddies the music, in fact the clarity is breathtaking. The vocals and acoustic guitars on Elliot Smith's "XO" album sounded more believably real than I thought they were before. I loved the George Harrison influence on the sound of the slide guitar on "Oh Well, OK" -- all in all it's a great-sounding album!
Then again, that's what the best tube components do, they gingerly goose up the music's tonal palette, but the tubes still sound clear and powerful. Solid-state headphone amps may be more accurate, there's no denying that, but for some audiophiles the glorious sound of a well-designed tube amp is impossible to resist. My old Grado RS-1 headphones, which aren't so proficient with low-end gusto, sounded bigger and bolder than they do with solid-state amplifiers.
With every music genre and every headphone I tried, the WA7tp shined and I couldn't take my eyes off it!
The Woo Audio WA7tp Fireflies ($1,599, AU$2,399) is sold direct from Woo Audio with a 20-day return guarantee, but there is a 10 percent restocking fee. The standard Woo Audio WA7 Fireflies amp that uses a smaller solid-state power supply instead of the tube power supply sells for $999, AU$1,799.