Review: Woo Audio 6 (WA6)

[Asr]

Intro

As mentioned in my previous review of the Shanling PH3000, I'm really no longer writing reviews, but I recently had an opportunity to check out the Woo Audio 6. Thought I might as well write a review of this amp too while I was at it.

Like the Shanling PH3000 review, this too was accelerated - all listening here was also done in 4 days, so this can be considered more of a mini-review than a full-length one.

Associated Equipment

Power cord: Black Sand Silver Reference MKV

Digital source: Plinius CD-101

RCA interconnects: Analysis Plus Silver Oval

Comparison amplifier: HeadAmp Gilmore Lite (used only as a reference point of contrast)

Headphones: AKG K701 (re-cabled w/ SAA Equinox), Audio-Technica W5000 and AD2000 (both re-cabled w/ APureSound V3)

Evaluation CD Tracks

A Fine Frenzy - One Cell In The Sea - "The Minnow & The Trout"

Alison Krauss & Union Station - New Favorite - "Let Me Touch You For Awhile", "The Lucky One"

Alison Krauss & Union Station - So Long So Wrong - "Little Liza Jones"

Porcupine Tree - In Absentia - "Blackest Eyes", "Trains", "Lips of Ashes"

Priscilla Ahn - A Good Day - "Dream"

Rachel Portman - Chocolat [OST] - "Main Titles"

The Crystal Method - Tweekend - "Murder" (aka "You Know It's Hard")

The Prodigy - The Fat of the Land - "Smack My Bitch Up"

Vienna Teng - Dreaming Through The Noise - "Nothing Without You"

Features, Operation, etc.

The WA6 was heavier than expected - looks compact but with clearly substantive weight, primarily from the dual power transformers. Relatively nice-looking amp too, with a clean finish that can come in either silver or black.

Not much in the way of features, but the amp does have an impedance selector switch that flips between 8-99 Ohms and 100-600 Ohms. I flipped the switch to 100-600 Ohms and plugged in my Audio-Technica AD2000 to check for noise - and found the tubes to be completely silent. Literally the only noise that could be discerned was a very low-level hum from the power transformers. The lack of tube noise was amazing, the WA6 is the first amp I've found to have absolutely no audible noise from the tubes.

I neglected to check if the impedance selector switch actually changed the gain multiplier or just increased the output power.

Sound - with K701

On Priscilla Ahn's "Dream," the WA6 placed Priscilla Ahn's voice closer than the Gilmore Lite did, for a more intimate presentation. The added prominence felt like a detraction though, and reduced the sense of overall depth to the soundstage. There didn't seem to be much air around the instruments. Treble was also not as sharp as the GL's, and not in a good way - there was a severely noticeable lack of razor-lined edges to the guitar strings. Dynamics also seemed to be a bit restrained compared to the GL, but the amp was still quite dynamic on its own.

On A Fine Frenzy's "The Minnow & The Trout," and Vienna Teng's "Nothing Without You," the WA6 gave a softer tone to the piano keys than the GL, but it was still strong enough to convey proper dynamic range. It also gave a stronger lower-mid/mid-bass anchor that made the piano sound heavy and deep. Overall there was more fullness and body, and it was very fluid as well - long piano notes with strong decays, fleshed out very well.

AKUS' "Let Me Touch You For Awhile" revealed some serious detractions though. The WA6 was a tad sluggish on the bass action and not really rhythmic enough. There wasn't enough "spring" to the guitar or mandolin notes either. Dynamic range also seemed to suffer here - the track overall felt too loud, with not enough contrast between softer and louder parts.

And on "The Lucky One" also by AKUS, while the WA6 removed a sense of Alison's voice carrying on air, it did make her voice sound more luscious and sultry. It was also positioned more closely/intimately and much more fluid. As far as detractions here, the WA6 missed conveying the metallic overtones and pops on the steel guitar, and the ambient air and space also felt significantly reduced - enough that the sense of space felt more like an enclosed studio room as opposed to an open hall. The various instruments comprising the band were discretely positioned though and were easy to locate by ear.

Porcupine Tree's "Blackest Eyes" went ok on the WA6 but not particularly great - the amp wasn't totally aggressive and dynamic on the opening overdriven guitars. It lacked a sense of brashness and intensity. It was still very dynamic though, and exuded its own confidence and power. It also separated the multiple guitars well to line up a convincing soundstage. Its presentation was also very direct - almost borderline in-your-face, but still a sense of some air around the band to not sound too suffocating.

Sound - with W5000

Revisiting Priscilla Ahn's "Dream," the WA6 paired well with the W5000 - although a closer, more intimate presentation, the W5000's intrinsic soundstage created a good outward curve to the image - that may still be too intimate for some people. The track was highly fluid with the W5K but not overly so, with a bold mid-range and strong firm bass. The lack of treble on the guitar was even more noticeable with the W5000 than the K701 though.

On Porcupine Tree's "Trains" and "Lips of Ashes," the most noticeable detraction was in treble extension, as it was audibly rolled off, but in spite of that, both tracks still sounded relatively good. The amp also gave more substance and body to the male vocals than the GL which was nice.

Rachel Portman's "Main Titles" from Chocolat [OST] went very well with the W5000 - the amp organized the soundstage much better than the GL. The individual orchestra sections were placed more realistically with percussion & strings on the left, brass and woodwinds in the center and center-right. It wasn't exactly as wide a soundstage as the GL, but there seemed to be more discrete horizontal positions within the image. There was also a better sense of depth in relation between the violins and the flute, as the flute felt distinctly further away.

Sound - with AD2000

On The Prodigy's "Smack My Bitch Up," the WA6/AD2000 pairing had its quirks. The GL had the clearer bass, as the WA6 felt a tad indistinct, even almost had what could be called generic-sounding bass. It was also less agile and didn't power through the bass as deftly. But it did pump up the >50Hz area for a nice added punch and boom that felt more satisfyingly deep. It didn't take much away from the AD2K's inherent speed - slightly less, but not too much that it made anything sound too slow.

The Crystal Method's "Murder" went worse for the WA6. Bass on this track sinks to a lower level than The Prodigy track, and the WA6 struggled to deliver it, it just didn't sound low or deep as the GL does, which maintains clear control over the low bass current. TCM's "Over The Line" is another bass reference, and it was here where it was obvious that the WA6 amped up 50-70Hz more than the GL, and 30-50Hz less than the GL, as it simply conveyed more impact than it did rumble (and conversely, the GL conveyed more rumble than impact). There was audible bass roll-off on the WA6, approximately around 40Hz. The amp just didn't creep or ooze low bass.

For a non-electronic test, both Vienna Teng and and Priscilla Ahn tracks were spun on the AD2000. The WA6 had the more realistic imaging than the GL. There was maybe less horizontal span than the GL but it was very integrated, very rounded, and very existential. The amp gave a proper impression of weight and realism to both voices and instruments.

Conclusion

The Woo Audio 6 is a solid tube amp all-around. I found it to have some key flaws but none really take away from what's essentially a very decent amp that can work well with different headphones. It may not really be optimal for the headphones I tried it with, but it works well enough and may very well be acceptable for listeners not as discerning as I was.

Pics

(click for larger)

Edited November 20, 2008 by n_maher
OP requested edit

[riceboy]

Thanks for the great review ASR. I am curious about the WA6 as well but more so the WA6SE or WA5. Thanks again

[spritzer]

Just to clarify, since the WA6 has output transformers the impedance switch is used to switch between two different windings to provide a better match to the load.

[Voltron]

IntroAs mentioned in my previous review of the Shanling PH3000, I'm really no longer writing reviews, but I recently had an opportunity to check out the Woo Audio 6. Thought I might as well write a review of this amp too while I was at it.

At some point, Steve, are you going to stop saying you don't write reviews anymore at the top of your reviews?

[Asr]

If a moderator could fix this bolded part to change the period to a comma (in the AD2000 section), I'd appreciate it:

The Crystal Method's "Murder" went worse for the WA6. Bass on this track sinks to a lower level than The Prodigy track, and the WA6 struggled to deliver it, it just didn't sound low or deep as the GL does. which maintains clear control over the low bass current.

At some point, Steve, are you going to stop saying you don't write reviews anymore at the top of your reviews?

Heh, well I'm only going to be writing 1 more kind-of-a-review on Head-Case, so you could say I'll be stopping that soon. These Woo Audio 6 and Shanling PH3000 ones were completely unplanned/unforeseen.

[n_maher]

If a moderator could fix this bolded part to change the period to a comma (in the AD2000 section), I'd appreciate it:

Done.

[postjack]

Heh, well I'm only going to be writing 1 more kind-of-a-review on Head-Case, so you could say I'll be stopping that soon. These Woo Audio 6 and Shanling PH3000 ones were completely unplanned/unforeseen.

here's to more unplanned/unforseseen reviews in the future. thanks for the write-up.

[hew]

here's to more unplanned/unforseseen reviews in the future. thanks for the write-up.

x2

[Beefy]

Nice write up

I'm always curious as to whether the upgrade packages that Woo Audio offers actually make any difference to the sound quality. As in DBT-noticable-improvements, versus audiophile babble......

[Upstateguy]

Thanks for the review. :D

USG

[Luminette]

Nice write up

I'm always curious as to whether the upgrade packages that Woo Audio offers actually make any difference to the sound quality. As in DBT-noticable-improvements, versus audiophile babble......

imo the upgrades hardly do much - a/b'd with a maxed out version and while a difference is there, mostly in high extension, it is so very minimal the idea of paying that much more is ultra silly

[HeadphoneAddict]

You really want to try the WA6 with a Sophia Princess 274b rectifier and RCA 6DE7 tubes with the shield between the two sections inside the 6DE7. That sophia makes a big improvement vs something like a GZ34 or Sovtek 5U4G rectifier. I think the tubes are more important than the mods.

PS: I didn't like the W5000 or AD2000 with the WA6 either, and with my tubes I feel it is better suited for my Grados, HD600, Edition 9 and D2000 (in that order). The bass is much better with RS-1, HP-1000, and HD600 but gets a little flabby with PS-1, D2000 and Edition 9 (in that order).

[DoubleEs]

Do you know if you can use a Sophia Princess 274b on a stock WA6?

[donunus]

From reading the review, my gilmore lite is looking like a formidable opponent to the wa6. But with my hd600s the glites are a little dry and uninvolving. hmm, I still have yet to see someone with the glite and a good tube amp like the wa6 compare them using the hd600s

[donunus]

By the way, asr... When you reviewed the wa6, did you leave the switch at 100 to 600 ohms? You never mentioned switching it back to the low impedance setting

[Asr]

From reading the review, my gilmore lite is looking like a formidable opponent to the wa6. But with my hd600s the glites are a little dry and uninvolving. hmm, I still have yet to see someone with the glite and a good tube amp like the wa6 compare them using the hd600s

IMO, the Gilmore Lite does a lot of things right that few amps at its price level beat. It's not perfect though and I wouldn't necessarily call it a formidable opponent to an amp of a different type - solid-state has its place as do tubes. Also I don't view amps as "tone controls" (well unless you're switching amp types, or rolling tubes in a tube amp) so if you want more coloration to the HD600, I'd sooner recommend a headphone change or a source change. The HD650 has a warmer mid-range and fuller mid-bass than the HD600 for example, if you like the HD600's type of sonic signature.

By the way, asr... When you reviewed the wa6, did you leave the switch at 100 to 600 ohms? You never mentioned switching it back to the low impedance setting

I set the switch to 0-99 Ohms for the two Audio-Technica headphones and 100-600 Ohms for the K701.

[HiWire]

So it sounds like a tube amp... j/k

Good review! I wonder how their solid state amp compares to the Gilmore Light.

I agree about the tone control - if you're buying an amp to fix your sound, you're probably doing it wrong.

[donunus]

IMO, the Gilmore Lite does a lot of things right that few amps at its price level beat. It's not perfect though and I wouldn't necessarily call it a formidable opponent to an amp of a different type - solid-state has its place as do tubes. Also I don't view amps as "tone controls" (well unless you're switching amp types, or rolling tubes in a tube amp) so if you want more coloration to the HD600, I'd sooner recommend a headphone change or a source change.

What I feel with my hd600 is that the glite doesnt take control of the bass... Many headfiers think this is due to the amp lacking in power compared to a tube amp with lots of voltage for the high impedance cans and not a function of this amp not being a tone control. Do you believe this is the case or have you not heard the glite hd600 pairing?

[Asr]

I haven't compared the HD600 among various amps so I can't say for sure how to get more bass out of it, but if there are any amps to add bass, a tube amp might be a good starting point - not all tube amps have a stereotypically tubey sound though, so look around.

[donunus]

Not really to add bass as much as grabbing it by the balls and giving it speed. People say the hd600s bass basically become ad2000 bass once powered right. wonder if this is hyperbole or the actual truth. That is the one thing I really miss with the ad2000s. The speed and powerful feel with almost any amp. Now if it only had the hd600s mids

[Asr]

Not really to add bass as much as grabbing it by the balls and giving it speed. People say the hd600s bass basically become ad2000 bass once powered right. wonder if this is hyperbole or the actual truth. That is the one thing I really miss with the ad2000s. The speed and powerful feel with almost any amp. Now if it only had the hd600s mids

This is just a guess but I bet if you ran the HD600 in balanced mode you'd get what you want.

[HeadphoneAddict]

This is just a guess but I bet if you ran the HD600 in balanced mode you'd get what you want.

I agree, so now donunus needs a good balanced amp, and SP is out (as much as I love the Square Wave XL) until Mikhail gets his act together. His budget is tight, so that leaves the Little Dot Mk VI and the noisy fan, or a Headroom Balanced Desktop. I've heard the Headroom at the July meet and it was very nice but 2x his budget.

However, the WA6 maxed with pseudo dual power supply and sophia princess 274b rectifier is VERY good with the HD600, and extremely close to balanced. You get all the tubey goodness, sparkle and spaciousness and separation with good bass and power, with a nice night-light to keep the under bed monsters away. Problem, out of budget again.

[Beefy]

... but 2x his budget. ... out of budget again.

...... that, or a balanced CKKIII.

If it needs sex-ing up, throw some Black Gates in there and call it a Maxxxxxxxxxxed CKKIIIIIIIIIII. Even then there would be money to spare.

[HeadphoneAddict]

Or, how much does a balanced M^3 cost?

[grawk]

A balanced M3 can cost as much or as little as you want it to

Mine, uh, wasn't cheap