Woo Audio WA6-SE impressions

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by will_f, Apr 16, 2020.

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  1. will_f

    will_f Friend

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    I couldn’t find any thread (or any posts really) on SBAF dedicated to the well known and respected Woo Audio WA6-SE so I thought I would start one and share my impressions after a little more than a week of careful listening.

    Why a WA6-SE?

    I wanted a well made, all tube SET Class A amp that was reasonably powerful, didn’t require unobtainably expensive tubes, handled a wide range of headphone impedances, and sounded musical and euphonic without breaking the bank.

    The Woo WA6-SE caught my attention fairly early in the hunt. The reviews were consistently good if limited in number, the minimum output impedance was a manageable15 ohms, the power output was a very respectable 2W at 32 ohms, and for a beautifully hand built, point to point wired, all tube amp, reasonably priced. I probably could have saved a fair bit of money with a less fancy case, but the solid, overbuilt nature of Woo equipment speaks to me. I don’t like to pay huge amounts of money for tubes, and the WA6-SE driver/power tubes are inexpensive compared to some more popular tube types.I nterestingly, the tubes Woo used have both a driver circuit and a power circuit in the same tube.

    What am I Comparing it to?

    I’ve had a Lyr 3 for I think a couple years now and I know it pretty well. It’s an excellent amp capable of powering almost any headphone with confidence. It’s strong points include really solid bass and exceptional clarity. My current tube, a Psvane CV-181 TII, gives the amp excellent imaging and soundstage. It has no bloom at all and is very neutral. The bass is clean and distortion free into the sub bass. The treble has just enough smoothing to take out the sometimes metallic sound of my Focal Clear. Overall it’s not very tubey sounding, but not strictly solid state either. A good blend of both.

    What have I tweaked?

    The WA6-SE came with the base factory tubes. I have Sylvania NOS coming to replace the stock driver/power tubes (so nice to pay less than $25 for quality NOS matched tubes) but for this listen I used the factory driver / power tubes. I swapped out the stock cheapie rectifier with a Sophia 274B “mesh plate” because it looks cool. I didn’t give the stock rectifier much of an audition so I can’t tell you personally if the Sophia is an improvement, but there is a very good thread on Head-fi that considers the stock rectifier complete trash.

    Is it well made?

    The Woo is, by far, the most nicely made amp I’ve owned. It is overbuilt in every possible way. The case is made from thick anodized aluminum. The power supply and amplifier are connected with a heavy umbilical cord and the combination weighs 22 pounds. All the connectors on the back are Woo branded and lined up at the same angle. The volume and power knobs are made from solid machined aluminum. The labels for the tubes and the Woo Audio name are all deeply engraved into the enclosure. The sense of solid quality this thing projects is like the audio equivalent of a Rolex. After multiple days of running, it’s barely above room temperature, giving me confidence it will last forever. It is obvious that Woo set out to make an amp built to last a lifetime, which I really admire.

    Testing Method:

    Unless stated otherwise my listening on the Woo was primarily with the low impedance (15 ohm) output since most of my phones have less than 100 ohms impedance. The exception being the HD6XX at 300+ ohms.

    My evaluation method was as follows: I listened exclusively to the WA6-SE for a week and simply enjoyed myself. Then I listened to my Lyr 3 and made note of the differences. After that I put together a list of some of my favorite music for the week and switched between the amps frequently as I played passages over and over to verify my impressions.

    My equipment connected to this amp is pretty decent but nothing exotic. Most SBAF members would call it Mid-Fi. Most non-audiophiles would call it extreme audio lunacy, but I’m still under $5K so what do they know? The full chain is Pi2AES transport streaming red book or better, RCA coaxial into a Schiit Bifrost 2, then into a Schiit Saga S so I can switch quickly between my Lyr3 and my WA6-SE with matched volume. I used 4 different headphones:


    • Sennheiser HD6XX with factory pads

    • Mr Speakers Aeon Flow Closed with black filters only

    • Focal Elex with factory pads

    • Focal Clear with factory pads
    How does it Sound?

    Initial impression with no break-in and stock driver tubes: Really good. No problems like hum or microphonics. Wetter than the Lyr3 but not by much. Mids are a little more forward but very clear and detailed. Headstage is quite different- further back- more in the audience and less on stage with the musicians. Plenty of power for all my phones.

    After less than 50 hours of break-in, detail and dynamics are excellent. Better than the Lyr with some headphones. A reduction in sibilance compared to the Lyr 3. It’s got a little more air on top than the Lyr with similar levels of clarity. None of that really matters though because the differences are not significant enough for me to choose one amp over the other. What does matter is that it just sounds good. What my Bifrost 2 did to the bass, the Woo does to the midrange. It sounds fuller, more musical, more euphonic, more real. Additionally, the imaging is excellent- better than the Lyr 3 with my favorite tube. The timbre is pretty much neutral, though the 15 ohm output impedance did cause my Clears a bit of bloom in the bass. Percussion is outstanding. Woo recommends a 150 hour break-in so further improvement may occur but I didn’t notice much change past 50.

    Impressions with different headphones:

    Focal Clear- this is my favorite headphone with the Lyr 3 because of its clarity, resolution and dynamics but it can be a little dry and analytical. Compared to the Lyr 3, the Woo emphasizes and adds some cloudiness from upper bass the down to the low bass. The result is a warmer signature with a touch of bloom. The Lyr 3 is less colored and sounds clearer and cooler and with a little sibilance. The Woo is less fatiguing at moderately loud volumes. Bass is where the Lyr outperforms the Woo, though the Woo has better micro dynamics, mids detail and separation, not to mention imaging. Both avoid the metallic character Focals (and Aeons) sometimes exhibit.

    Focal Elex- Similar to the Clear though I prefer the Elex- tighter bass with no perceptible bloom. I suspect if the Clear were a little higher impedance the overall sound signature would be extremely close. The Elex synergizes with the Woo very well and delivers a little more clarity than the Clear. If you’re looking for clarity, detail, dynamic detailed bass, great imaging and sweet mids it’s a great pairing that exceeds the Lyr 3 / Elex combo and IMHO the Woo / Clear combo.

    Sennheiser HD 6XX- This is a headphone that sounds much better on the Woo than a $200 headphone should. It’s not as technically capable as the Focals or Aeon, but when powered by the Woo it’s strengths are on full display.The HD-6XX is relaxing and euphonic with both the Woo and the Lyr 3 but the Woo makes the excellent mids of the 6xx really shine.

    I tried both the high impedance and low impedance outputs on the Woo and I prefer the low impedance which to me sounded clearer and more resolving. Compared to the Lyr 3, the 6XX stage feels further away and larger. The treble is laid back so definitely not recommended for treble heads but it is extremely forgiving of recording quality.

    MrSpeakers Aeon Flow closed- This one was a surprise to me. I expected the high current / low impedance nature of the Aeon would make the all tube WA6-SE struggle, but it didn’t do too bad. The sub bass is rolled off a few dB and the bass isn’t as energetic as the Lyr, but that would be about my only complaints. Compared to the Lyr 3 the WA6-SE brought detail, micro dynamics and bigger soundstage plus it pushed forward the mids and added lushness while keeping the treble sparkle and the super black background. The bass sounds a little polite and the imaging isn’t as pinpoint as the Focals, but the end result is a slightly warm musical headphone with great imaging that delivers exceptional mids, clarity and detail. I’m thinking that a higher impedance planar like LCD-2 would probably sound fantastic on the Woo.

    In summary:

    The Woo is pretty new so I’m sure there’s a fair bit of “new toy syndrome” in my impressions, but without a doubt; it’s a great sounding amp and I’m surprised there isn’t more discussion about it. It has all the expected benefits of a good tube amp (sweet sound, great mids, great imaging and soundstage) and it sacrifices very little to get there (slightly rolled off sub bass). Also, it’s exceptionally well made for the price. It costs a lot more than the Lyr 3, but it wouldn’t surprise me if all the price difference is in the case. I don’t personally find the case any more attractive than the Lyr 3, but I appreciate the attention to detail and obvious quality. It’s pretty clear you’re getting your money’s worth.


    The Lyr 3 and WA6-SE sound quite different from each other. The Lyr 3, being a tube hybrid, has less SET tube character but delivers all the bass, energy and drive you would expect of a high power solid state amp and it adds exceptional clarity and a little tube magic on top. IMHO it’s a great choice for headphones that can take advantage of its clarity and excellent bass. It will drive just about anything well which makes it very flexible.


    The WA6-SE brings traditional tube sound without compromising technical performance much, exceeding the Lyr 3 in layering, imaging and micro dynamics. It has a lush, musical sound that plays reasonably well with all my headphones, but it prefers working against moderate to high impedance. It’s 2W output and 15 ohms of impedance can handle a fairly wide range of headphones, but not all (low impedance and low efficiency is not a good combo). It’s a good partner for analytical headphones that might be a little dry and / or bright.


    Am I happy with this amp? Absolutely. The quality of construction is through the roof and it delivers a beautiful tube sound that is a true pleasure to listen to. I consider it a total bargain for the price. I haven’t heard any other transformer coupled SET amps so I can’t compare it to the competition, but it absolutely holds its own with my Lyr 3. It’s probably not the best choice if you’re into tube rolling given the lack of information on 13Dx tubes, but the stock driver / power tubes sound great and if you do roll em, prices are reasonable. Highly recommended.
     
    Last edited: May 26, 2020
  2. YMO

    YMO it's not drinking alone if you're on Zoom

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    Good write up. I had the WA6-SE a few years back. It had a lot more power than the regular WA6, and back when I had the LCD2C it drive them just fine with da bass. However, to me it still sound like a stereotypical t00b amp with more power (thick, warm, slightly slow). I guess that was the real reason why I got rid of them.....

    Tube rolling on them does make a minor difference, but not a big one back when I had it.
     
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  3. Ntbm3

    Ntbm3 Friend

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    I also had a WA6-SE ver2 for most of last year.

    I found it to be a decent amp with plenty of power. I also loved the build quality.

    But... it did not consistently have the 'magic' I found with other tube amps like the bottle head crack ...I could not find good synergy with my DAC's and headphones I had. It might have been gimped by using SE out of my Gungnir A2. Not sure.

    It also had a high noise floor that was annoying. Especially with high impedance out.

    I played with a lot of tubes and rectifiers and moved things closer to my preference but in the end moved on to the DNA Starlett.

    I am very happy now.

    Edit: I feel like this was a bit negative, to the OP. Great write up! It just ended up not being for me. Enjoy your Woo!!
     
  4. will_f

    will_f Friend

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    I did look hard at the Starlet but at the end of the day $2K was more than I wanted to spend. I imagine it sounds fantastic though based on the reviews.

    No worries about negativity. I find audio perception (including my own) highly subjective and the differences subtle. I changed my mind about the Woo quite a bit when I started quickly switching between the volume matched Lyr and the Woo. Initially I thought the Woo was much tubyer, warmer and more rolled off on treble. That didn't hold up. I also initially thought the Lyr was a lot more dynamic but changed my mind on that too. The bass texture was noticeably better on the Lyr with my low impedance Clears, but really, the biggest difference was the Woo has better sounding mids to me.

    Re noise floor- I haven’t really used the high impedance output much so I can’t offer much opinion on that. All my headphones had more than enough gain on the low impedance output and with the exception of the HD6XX all are more suitable to the low impedance out. I haven’t noticed any noise, but no doubt it’s got to be higher than the Lyr.
     
    Last edited: Apr 17, 2020
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  5. will_f

    will_f Friend

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    Agreed on the slightly slow and stereotypical tube sound. That was what I was looking for. For me it is just the right amount. Maybe it’s my age And the fall off in high frequency hearing, or possibly my choice of headphones, but I really like what tubes do to the sound for most of what I listen to. The irony of spending much more than what my Magni 3 cost for more distortion and noise isn’t lost on me, but I know what I like
     
    Last edited: Apr 17, 2020
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  6. will_f

    will_f Friend

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    After cogitating on this for a day: I’ve concluded the Woo works best with the following headphone attributes. I would guess headphones that don’t meet most to all wont sound great:
    • Impedance of at least 80 ohms (to avoid too much coloration from impedance variation of the driver).
    • High efficiency (because even though the woo can deliver a lot of power, it distorts least at low to moderate power)
    • Open headphones (because you want to hear the coloration of the amp, not the headphone enclosure).
    • Good imaging and clarity (because tube amps can make these attributes shine)
    I think that’s why I like the Woo so much. It really sounds great with my Elex which meets the criteria. The 6XX also did exceptionally well, despite not being particularly clear or great at imaging. Not as satisfying are the Clear (lowish impedance) or the Aeon (power pig). I would guess the Woo would really shine with a Sennheiser 800 or 800s, a utopia, or similar.
     
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  7. will_f

    will_f Friend

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    Thought I’d add a comment about the NOS tubes I ordered. I’ve been listening for a few days and consider them a step up from whatever the Woo came with. When I first put the tubes in it was hard to hear a difference between the Woo and the Lyr 3. For a while I wondered if maybe I was suffering from some sort of hearing fatigue.

    Luckily, time passed. After 10-15 hours burn in, maybe a little more, the Woo developed the soundstage and separation the stock tubes had, but with tighter bass / a little less bloom / more resolution. I find myself enjoying my music collection like it’s all new again so I’d guess they’re more musical too.

    The tubes are late issue 13DR7 black plate Sylvanias rebranded as Zeniths. I’ll try to add a picture tomorrow.
     
    Last edited: Apr 23, 2020
  8. barbz

    barbz Rando

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    I have the woo wa6 and agree with your description of the amp - I find it enjoyable to listen to especially after using a different amp for a while and coming back to it.

    If you get a chance its worth checking out the Sylvania 13FD7 tubes for the drivers - Im not going to attempt to describe the change but it was a vast improvement over the stock tubes in my case.

    You may have seen this already and the below is stolen from head-fi (just substitute 13 for 6)

    Code:
    "6DE7 - Fast transients, good for rock, pop
    6EW7 - Softer sound but slightly larger soundstage, good for some jazz, classical
    6CY7 - between 6de7 and 6ew7
    6DR7 - similar to 6de7 but higher gain
    6FD7 - punchy bass, large soundstage, fast transients"
    
    "6sn7 is super linear and offensive to no one's listening
    palate but the 6dj8 has a beautiful coloured tone that
    is addictive. it also needs the anode plate voltage to be
    lowered to around 130v for the 6dj8 and 150v for the
    6922 and 7308 to function a long time. it'll work fine at
    200v on the wa6SE without any resistor adjustments
    but i'm sure it'll lead towards an early grave for the tube."
     
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  9. will_f

    will_f Friend

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    Pic of the tubes:

    [​IMG]
     
  10. will_f

    will_f Friend

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    Thanks Barbz, I was thinking about picking up a pair of FDs and now I’m motivated to do it.
     
  11. will_f

    will_f Friend

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    So I did pick up a pair of Philco 13FD7 fat bottle tubes to try out:

    [​IMG]


    Truth is they don’t wow me. Admittedly they may sound better with more than 5 hours burn in, but I don’t hear the separation and layering of the Sylvania 13DR7s.

    They are warm with deep bass and punchy. The soundstage is very close and fairly wide. However, I’m not able to hear as much detail or resolution compared to the Sylvanias thanks at least in part to bloom. If I were to bet, I’d lay odds on a lot of higher order harmonics off the low frequencies. I’ve heard some reviewers describe a tendency for some amps to sound like warm poo. These tubes are what I imagine warm poo sounds like. I’ll report back if the sound changes, but for now I’d say Philco fat bottle 13FD7s are not something to seek out unless you like warm poo.

    Not that there’s anything wrong with that. It’s a fairly euphonic sound, just not my preference.

    edited: tried to better describe the sound.

    2nd edit: After another 15 or so hours: Not very neutral sounding, but much improved re soundstage (deeper) and layering. I am learning to like way it sounds- warm peanut butter texture with a punchy, organic character Like unpasteurized cheese a little past it’s prime.
     
    Last edited: May 9, 2020
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