Woo Audio WA5

General Information

* 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

Latest reviews


100+ Head-Fier
Pros: Dynamic, powerful, versatile, built like a tank, amazing parts quality
Cons: Large, heavy, likes expensive tubes to sound its best
This is my third Woo amp and by far my favorite. I owned a 6SE for two years, then sold it for a WA22 (which I still have). The 6Se had a nice warm sound, but the WA22 really took it up a notch, especially for balanced sources. The former owner of my WA22 raved about the WA5LE he had acquired, and I kept my eye open for a deal. I located this unit, which is a pre-2015 WA5.
There are very slight differences between pre-2015 WA5 versions and the current version offered by Woo. I verified with Woo that, except as indicated below, the WA5's circuit design, features, and construction has remained unchanged since the amp's introduction in 2008:
- inputs (the pre-2015 has 4 RCA inputs, the 2015+ offers only two RCA and one XLR pair of inputs but note - the XLR input is not actually a balanced design but just there for convenience.
- impedance and level switch - The pre-2015 amp gives you three basic output options using a selector knob: high imp, low imp, and a high power setting for the XLR output (suitable for the AKG1000). The 2015+ version deletes the high power setting and instead adds two toggle switches for power and impedance, which enable a slightly more tunable headphone impedance matching.
- switches: the pre2015 amp used round knobs for the input and output selector switches on the front of the amp. The 2015 plus switches over to flat switches which are easier to turn.
- parts upgrade: the pre-2015 offered the option to upgrade to ultra premium internal parts: (V-Cap input coupling Teflon caps, Jensen decoupling caps and voltage filtering caps, Black Gate bypass (6SN7 cathode) caps for an extra $1250, the current version includes these as standard 
- packing: Woo originally shipped the WA5 in wooden crates with foam inserts - they now ship in double boxed cardboard boxes with foam inserts. The wooden boxes are quite impressive, but they add to the shipping weight (and therefore the cost).
The WA5 LE differs from the WA5 in that it deletes the speaker terminals and ability to drive speakers, and the audiophile parts upgrade is an option. Compared with the upgraded parts included, the WA5 basically costs an extra $950 for the ability to power a pair of high efficiency speakers.
I used the following gear to listen to the WA5:
- Sony HAPZ1ES digital player
- Musical Fidelity Tri-Vista 21 DAC (fed with a highly modified Logitech Squeezebox and power supply, for streaming Tidal)
- VPI Prime turntable with an EAR 834p phono pre amp
The WA5 was....one of those jaw dropping moments in hi fi for me. I've owned high end tube gear for a number of years powering speakers, and the Woo WA6SE was my first tube headphone amp. The step up to the WA22 was noticeable - but really more for using balanced sources - and the WA22 seems very finicky about tube choices in order to maximize the tone. The WA5 was simply magnificent regardless of source, and regardless of tube choice. I started with the stock tubes, but swapped the 300b's for some Genelex tubes, swapped the 5AU4's for some Sophia Princess 274's, and used Sylvania and RCA 6SN7s. The better tubes improved things, but not to the extent they did on the WA22.
Immediate reaction using the HD650s and LCD3s - sheer dynamics and power, amazingly controlled and extended low end, and a rich and open midrange. The WA22 paired nicely with the HD650, but the WA5 took everything up several notches, and helped to expand what has been called a darker top end on the HD650. The more impressive pairing was the LCD3. This amp just sings with the power and the control that a high power amp like the WA5 provides - I felt like I hadn't really heard the true character and virtues of the LCD3 until I hooked them up to the WA5. The low end was noticeably extended, the top end was as well, and the combination was magical. The LCD3 has a slight glare with the WA22 - very tube dependent, but the WA5 eliminated it.
Tonight, listening to both phones, the word that comes to mind is "exquisite."  On the LCD3, the WA5 brings a realism and tone that are so honest and real. The retrieval of detail is wonderful. Switching to the HD650, I lose some of the microdetail, attack and low end bass extension, but the musicality and tone are still there - warm and open.
The thing about the WA5 is that it so changes the character of the phones, I feel that only with the WA5 am I hearing how they truly sound. On the 6SE, I heard the nice Woo character traits, but the phones were not as dynamic or vibrant, especially the HD650. And the LCD3 has a glare and haze that disappears on the WA5. On the WA22, the HD650 pairs wonderfully, and the gap between the WA5 and WA22 is closer than on the 6SE. But with the LCD3s, things change radically - the WA5 shows me why I paid $2k for these phones. With the HD650, the WA5 tells me the Sennheiser is not veiled or dark on the top end as much as everyone complains, it just needs more power to come to life.  
My amp had to go back to Woo for repairs when it first arrived from my seller - among other things, they replaced the volume switch, selector switch, a tube socket, and reinforced some solder joints, and inspected the amp overall, plus replaced some defective tubes. In that time, I had a chance to return to the WA22 and enjoy its virtues, which are many. Upon return of the WA5s, I spent more time listening through a pair of ProAc mini monitors I had acquired. Even though the WA5 puts out 8 wpc and the ProAcs are 89db efficiency (and 8 ohm impedance which does not dip much), the match was a great one - the WA5 lets the ProAcs image and soundstage effortlessly. I wasn't expecting much as  speaker amp, but the WA5 delivered handsomely - enough such that I don't miss my older higher powered Air Tight 120wpc monoblocks.
Quibbles? Just a few:
1. The amps are large - they will fit on a standard rack but take up the whole shelf. As a desktop HP amp, these are like having twoWA22s
2. The amps are heavy - 45 lbs in each wooden box shipped, which costs about $130 to ship to Woo.
3. 300b tubes aren't cheap - the Genelex upgrades cost about $325/pr, and there are far more expensive options.
4. Ok - this is reaching, but none of the Woo amps offer remote control. This is really only an issue if you are using as a speaker amp.
5. the umbilical cable is a pain to hook up if you don't have easy access to the rear of the amp panel, such as when putting into an enclosed cabinet.
I'd love to hear comparisons with some other highly regarded HP amps, like the Cavalli, or the Violectric, but I am guessing the WA5s belong in the rarified air of amps, where the differences are those of tone, not capability.
All in all, a most impressive and magical amp, and easily the best I've heard from the Woo lineup (I have not heard their exotic monoblocks), and the ability to play speakers through them helps to justify the significantly high price.
  • Like
Reactions: maystor


There are no comments to display.