Amplifier unit on the left, power supply unit on the right
WA5 amp unit on the front, power supply unit on the rear
Power supply unit on the left, amplifier unit on the right.
Amplifier unit front panel
Front and right side.
Close up front
Rear panel and right side
Rear panel and right side
Rear panel and right side
Dependable packaging - AMP and PSU ship in a molded foam within a custom made wooden crate.

What I wanted to hear was a magic midrange, full, lush sound and that 3-D impact that single ended 300B amps can deliver. I wanted this sound but not the $20,000.00 price tag that goes with it! The Woo WA5 delivered. - Steve Hoffman Link to Tone Audio

After long stretches of wee-hour listening without any fatigue -- that's a biggie with these cans as only those who own 'em will fully appreciate -- I can squarely say that the Woo right off cleared the biggest hurdle any K amp has to clear before I'd even consider going further. - Sranjan Ebaen at 6moons.comLink to Tone Audio

Major Headphone Amplification! - TONE AudioLink to Tone Audio

I am completely blown away by the naturalness of the music, the realness of the sound. I listen to a lot of classical and jazz, especially small classical ensembles, piano, violin, cello, that type of music, and it is simply put, a fantastic sound coming from the W5. My K1000 have never sounded this smooth and enjoyable, with NO ear fatigue, no etched treble, and plenty of good clean bass. Not only do the K1000 sound great, but so do speakers on the W5! - by stax-i-nox at head-fi.org

The bass has more detail, impact, depth than I originally thought. During even complex jazz riffs the notes have a very distinct leading edge, sustain and decay.

Male and female vocals are presented with warmth and wonderful tone, Seal comes to mind with a lot of texture and impact.

The high end has an interesting dual effect going on. Sharp focus and detailed, but at the same time have a wonderful since of air about it. At first this seems like it isn't right... I guess the better thing to say is that each instrument (or notes) have a distinct location in a 3D soundstage, but within in that space the instrument (notes) have room to breath. So it is not edgy, just that balance of detail, and warmth.

All of this provides a quality that allows me to listen at lower levels, because the control, detail, and depth are higher.Link to original post

I had never heard a SET amp before, but had read a lot about that SET magic and had an idea of what to expect- smooth fluid mid-range, a lot of low level detail, huge and detailed soundstage, and weak in the bass. To my delight I found the WA5 had all of these traits.Link to original post

What I can say is the 274B has a very different character from the GZ34 metal base. It is far from subtle. First there is more bass - both in terms of quantity and depth. Second, the overall sound is richer, or I should say, denser across spectrum. Some people may call it "sweet" but not syrupy. Third, the far end treble is not as detailed as the GZ34 and tends to roll off earlier. Overall, it is a very different presentation from the Metal Base GZ34. - fkclo at head-fi.org

Price: $3150

* AMP and PSU ship in a molded foam within a wooden crate

* Power supply umbilical cord is included.

* 1 pair of 300B, 6SN7, and 2 tube rectifiers are included.

* AC Power cord and RCA interconnect cables are not included.

* Shopping cart applies to the U.S. buyers only. International buyers please contact for shipping cost and payment instruction.

    Technical Specifications:
  • Two 300B [PDF] power tubes
  • Two 6SN7 [PDF] drive tubes
  • Two 5U4G [PDF] rectifier tubes
  • Voltage: AC 110/220V, 50/60 Hz
  • External dimension (each): 8½(H), 9"(W), 17"(D)
  • Weight: Amp Unit: 35 lbs, Power Supply Unit: 40 lbs
    Headphone Amplifier Specifications:
  • Headphones impedance : 8-800 Ohms
  • Frequency response: 10 Hz—60 KHz, -2dB
  • Power output >= 1.5 watt
  • Signal/Noise: >= 95 dB
  • THD: <= 0.08%, 1Khz
    Speaker Amplifier Specifications:
  • Power output: <= 10W x 2, THD <= 3%, 1Khz
  • Frequency response: 16—38 Khz, -2dB
  • Output impedance: 8 ohms
  • Signal/Noise: >= 90 dB
    Standard Features:
  • Independent headphone and speaker circuits
  • High-end output transformer design
  • Point-to-Point wiring
  • Selectable speaker, AKG-K1000, high and low impedance dynamic headphones output switch
  • One 1/4" headphone jack and one XLR connector for K1000
  • Four pairs of gold-plate RCA inputs
  • Selectable inputs switch
  • Two pairs of gold-plate speaker terminals

Parts upgrade: $1100
Premimum parts upgrade package.
(Parts upgrade are intended for amplifier purchase, not to be sold on a standalone basis.)

We carefully selected the best possible audiophile graded parts that bring the ultimate performance from the amplifier.

  • V-Cap input coupling caps. Matched pair 0.15uf/600V
  • Jensen voltage filtering caps, 220uf/450V
  • Blackgate bypass (6SN7 cathode) caps, 220uf/160V
  • Blackgate bypass (6SN7 cathode) caps, 220uf/16V
  • Blackgate bypass (300B cathode) caps, 470uf/160V
  • Mills load resistors (300B), 750 ohms, 50W
  • Mills load resistors (6SN7), 22 kohms, 12W
  • Mills cathod resistors (6SN7), 7.5 kohms, 5W
  • Kiwame cathod resistors (6SN7), 330 ohms, 2W
  • Kiwame cathod resistors (300B), 330 kohms, 2W
  • Jensen decoupling caps, 100u/500V

Teflon tube sockets upgrade:
$150 (8-pin x4, 4-pin x2)
Teflon is a superior material with great isolation and tempreture endurance. The unique design of multiple pin contact area greatly increase connectivity and gripping. Pins are gold-plated over oxygen free copper.

Click to see details 2 3 4

Power tubes upgrade 1:
Shugang 50-Years Treasure 300B matched pair, Grade A. $600 with 12-month warranty, sourced from Grant Fidelity

These are incredible detailed, excellent image, great speed, lush mid range, extended high end, and yet the most authority bass a 300B can produce. Indeed, the Treasure 300B is one of the most favorites for the WA5.

The Treasure series is a statement work of Shuguang's 50-years' of expertise in vacuum tube design and production, a highest quality build. Its unique black glass is due High Polymer Compound Carbon (HPCC) coating. Compared to traditional carbon spray technology, HPCC coating will allow greater concentration of electrons, enhance and maintain stability of the electron flow, maximize "secondary electron emission surpression" from the glass enclosure, in turn reduce effects of electron swirl which generates internal noises from the vacuum tube itself.

Power tubes upgrde 2:
Sophia Princess 300B Mesh Plate black base matched pair. $350
Comparable to Western Electric 300B. Buy and ship independently.

The result is a 300B mesh plate tube with super clarity, low distortion and out of this world mid range fullness and liquidity. High frequency extension and sweetness is the first thing you would hear. This is a true 300B tube that is 100% interchangeable with the popular Sophia Electric globe shaped 300B mesh plate tubes and Western Electric 300B tubes, as well as current production Chinese/Russian 300B tubes (with WE 300B standard).

Driver tubes upgrade:
Shuguang Treasure CV181-Z / 6SN7GT matched pair, Grade A. $320 (2 pcs) with 12-month warranty, sourced from Grant Fidelity

Low noise, very high resolution, extended full frequency range. True "Treasure" as a result of Shuguang's 50 years of expertise in vacuum tube design and production.

Rectifier tubes replacement:
Sophia Princess Mesh Plate 274B rectifier. $300 (2 pcs) with 30-day warranty
To impact WA5's sound quality or for your super backup. Buy and ship independently.

Sophia Electric™ 274B tube is a premium rectifier tube for a 5U4/5R4/5AR4 direct replacement with 3X longer plate structure, thus it has a deeper, wider sound stage and even smoothier sound than Mullard 5AR4.