The Woo Audio 2
Jan 17, 2009 at 6:25 AM Thread Starter Post #1 of 1,751


100+ Head-Fier
Feb 16, 2004
I received my WA2 today, and I've had a blast setting her up and having a preliminary listen. I know I have promised a lot of pictures/impressions/tube rolling results etc., so please be patient. All of that will be forthcoming. You can probably expect some daytime shots tomorrow, including the high-res interior pics so many of you have asked for. Let's see if we can figure out what they changed in the power supply. I will post some reasonably detailed first listening impressions tomorrow, as well, but for now, I will just say that she sounds fantastic. And man is she a beauty... None of the pics I've seen online so far come close to doing justice to this industrial artwork, but I will do my best to fix that.

So as not to completely disappoint you guys, I will throw a little teaser your way. Here's one shot of the beautiful glow - which is a comforting sight just a few feet from the window and the below-zero temperature (with wind chill) outside.


UPDATE - 1/17/09 : Photoshoot

I had a chance this morning to do a photoshoot. I have glamour shots and photos of the guts, so I hope I have lived up to what I promised. Let me know if you have any more specific photo requests, and I will hook you up whenever I can get some time. Without further ado, the glamour shots!













These still don't do justice to what it looks like in real life, but I think they'll give you a better idea than anything else out there. The black is just awesome looking, and even though it is hard to capture in photos, I would highly recommend it. I haven't seen the silver in person, but something tells me I would still prefer the black.

And now, for all you DIYers, modders, and solder-savvy types, here are the internals. I hope I've provided enough angles, but if you need close-ups or anything else, let me know. I would love to hear from you guys what exactly was changed with the most recent power-supply revision. It sure is neat and tidy, and it certainly looks well done. These guys definitely care about their work.







That's all for now. The pics took a long time, so I didn't get a chance to type up any listening impressions yet. Soon, though. I also haven't rolled any tubes yet. I have some good ones waiting, but I want to get familiar with the stock ones first. More to come soon.

UPDATE - 1/23/09 : Listening Impressions

After getting some more time to listen to the amp, I can share my first coherent impressions of the sound. Keep in mind, these all refer to the amp with stock tubes and limited burn-in. First, a few general characteristics of the sound signature.

First of all, with the WA2, you get the music and nothing else. The sounds rises up from a completely black background - something that makes more of a difference than you would think. With both the GS1000s and HD650s, I can turn the volume to max with no music playing and hear absolute silence. Extremely quiet passages are breathtaking with this amp - but make sure you don't have ambient noise if you're using open phones. A computer fan, heat/AC unit etc. can become noticeable and annoying when using an amplifier with such a low noise floor.

One of the great strengths of this amp is dynamic range. It seems to have massive power reserves, and it really does justice to recordings with very wide dynamic swings (think well-recorded large scale orchestral music, string quartet, opera etc.). If you own this amp, you owe it to yourself to put on such a recording with the lights off and listen to how well it handles transitions from whisper-quiet muted strings to thunderous orchestral tutti passages. In my opinion, authoritative dynamic range is one of the most important criteria in making recorded music sound realistic and also one of the most difficult to achieve (not least because the current recording industry actively ruins and removes any dynamic range that was originally present in many recordings).

For those of you wondering about whether this is a "warm" amp or not, or how detailed it is etc., here is what I would say so far. Compared to most solid-state amplification I have heard (which does not include any super high-end stuff), I would say that your first instinct would be to say that it is a little warmer. However, after spending some time listening specifically for this characteristic, I am confident in being able to say that I notice very little, if any, low-midrange emphasis or "tubey" rolled-off highs and lows. The extension is fantastic in both directions with this amp, and I do not notice any lack of detail in the treble. I think the main difference is that the WA2 has a superb ability to render harmonics and acoustics. I feel like I hear more of the overtones of acoustical instruments, which produces a richer sound, but more importantly, they sound more like the same instruments sound in real life in a real space. Each instrument's unique timbre is a result of its overtone series, and the WA2 does an exceptional job delivering all of those overtones in addition to the fundamental. In fact, tone and texture might be one of the first things to impress you after powering up the amp for the first time. People often complain about "one-note bass" when they are not happy with the low-frequency performance of a source, amp, or transducer. Well, that is caused by a lack of ability to produce the harmonic information we have been talking about, leading to all bass instruments sounding indistinguishable in tone. The WA2 is like the polar opposition of "one-note bass" throughout the whole frequency spectrum. Tone and texture are probably its greatest strength among its many strengths, and I am very hard to impress in this area. It is the one criterion which I simply must be satisfied with if I am to like a piece of equipment, and the WA2 has provided more of an improvement in this area than any other addition to my system (not counting transducers, which obviously change the overall sound more than anything else by nature).

Another closely related strength of the WA2 is its ability to transmit the acoustical surroundings in which the recording was made. Live recordings sound live, with the particular sound of the venue clearly present. I have been noticing all kinds of acoustical cues in recordings that I hadn't heard before, and again, this is one of the most important aspects of making a recording sound realistic. I can hear if a hall is over-resonant in the bass because I can hear the faint rumbling vibration hanging over longer than the reverb from higher-pitched instruments. I can hear if it's a very dry venue in the emphasis on the fundamental tones and lack of bloom in plucked notes. Small things, certainly, but they make a big difference.

I have been impressed with the amp's ability to layer music and created a terraced presentation rather than a muddled mass of sound. Orchestras are full-sounding as they should be, but each section is clearly separated from one another. Chamber musicians play in concert with one another, not on top of one another. In busy electronic mixes with electric guitar, drums, synths, computer loops etc., it is very easy for it to all just mash together and make a muddled mess. And I'm not saying the WA2 can rescue a recording from this if the engineers screwed it up in the studio because it can't. But with good recordings, the WA2 will give you all the various sounds in their proper place. This is a characteristic difficult to describe in words, but other WA2 owners probably know what I am talking about. Just listen to Radiohead, the Decemberists, Broken Social Scene, the Stars, or anything else that is densely layered, and you will hear it.

The only thing I've heard that I might consider a minor weakness so far is that on some recordings, the bass could be a bit tighter. On most recordings it's perfect, but every once in a while I wish for just a bit less bloom in the lowest frequencies - mostly with electric bass. I have had no complaints with bass in acoustic music (in fact it's been excellent), so I have a feeling that the fault is more with the recordings, but I think the amp could do a tad better controlling it. Something tells me the 5998s I have sitting here will make any reservations on these few recordings go away.

I hope that gives you an idea of how I perceive the overall sound signature of the WA2. This is not an amp that has an obvious, immediately-identifiable trademark sound that you will either love or hate right away. If you have competent amplification already, you probably wouldn't fire up the WA2 and immediately shocked by the difference in sound, and you probably wouldn't want to be. Amps should not be drastically altering the frequency response of your system. I think people on this forum build up far too much anticipation for people buying their first high-end headphone amp. If your headphones are getting a sufficient amount of power from the amp you already have, a high-end amp is not going to make you want to throw the old one out the window cursing it for all the music it has been withholding. The things that make it worth the expense and the designers time and effort are these subtle details that, over time, make the listening experience more fulfilling. Put on a demonstration disc and switch back and forth every 10 seconds listening for tiny differences and you might be disappointed. Spin up your favorite disc and listen to it all the way through on the WA2 and then again on your lesser amp, and you'll never question your purchase.

Headphone Pairing Impressions

Now a little about how the amp pairs with my headphones.

GS1000 - As I said earlier, I have never experienced an audio component so dependent on the rest of the system as the GS1000s. With inadequate, or even unsympathetic, components, these headphones are basically unlistenable. Even though I love them for a lot of music and they can do some things no other headphone I have heard can do, I still consider this a flaw in their design. Luckily for me, I believe the WA2 matches them as well as anything ever will. It has tons of power, which results in a significant boost to midrange bloom as well as bass control. Also, the amp has very extended but also extremely smooth highs, so while that GS1000 treble spike is still there, it is far less offensive. This allows the strengths of the phones to shine through. The bass is simply phenomenal - full but not slow, extremely textured, deep, and supremely musical. The mids show off the GS1000s near-perfect tonality, which I think is the real defining characteristic of these headphones. Instruments simply sound like they should - like they sound in real life. The brain has an amazing ability to adjust to deviations in what it expects to hear, so if I listen to a string quartet for 45 minutes on my HD650s, I don't really notice all that much that the instruments sound a little off compared to reality... until I switch to the GS1000s. How are the highs? Well, they're very present and a little aggressive right at the spot where they have the spike. There's no getting around that with these headphones. But they're tonally accurate, detailed, textured, and a lot more natural sounding than they are with any other equipment I've tried the GS1000s with, and it's hard to be bothered by them when everything else sounds so amazing. I still prefer the HD650s with most rock music and poorly recorded material, but the WA2 and the GS1000s are a wonderful combo.

HD650 - The Senns respond very well to such a powerful amp able to provide the huge voltage swings needed for a 300-ohm headphone. Everything is tighter and more authoritative, and the overall sound is more coherent. Highs are clearer and more detailed if not more present decibel-wise, and the smoothness of the phones is emphasized. These headphones are very versatile and certainly far less picky than the Grados, but they still reward the investment in great amplification. It's much more difficult to isolate one or two major changes in sound. They basically retain all of the same characteristics that they already had, but they just do everything better. Deeper, tighter bass. More textured mids. More extended, detailed highs. Deeper layering. Better dynamics. You name it.

HD800 - This combo is simply the greatest hea... Nope, just kidding. I'll have to let you know how they like each other in a month or so. Maybe they will combine all the strengths of the GS1000s and the HD650s and I won't ever have to choose between them again.

UPDATE - 1/24/09 : Tube-Rolling Impressions

I have now rolled in all of the tubes I have, which in addition to the stock consist of Tung-Sol 5998s, Amperex Bugle Boy 6DJ8s, and Amperex Treble Clef 6V4s. Each of them had a positive effect on the sound, and I will do my best to share what I found to be different. I rolled them one at a time in the order listed in order to try to isolate the changes made by each set of tubes. However, I did not switch back to stock tubes in each spot other than the one I was trying, so for example once I put in the 5998s, they stayed in the whole time. So I don't have any impressions on the new 6DJ8s combined with the stock power tubes or the new 6V4s combined with any of the stock tubes. Hopefully that makes sense.

Tung-Sol 5998s - These tubes are all about muscle. This is already a muscle-bound amp, but there is a definite sense of increased power with these tubes. The bass is more impactful and damped, and the overall sound has more weight to it. Think of the feeling you get with a nice full-range speaker system that really lets you feel the sound as well as hear it. The 5998s impart some of that feeling to headphones, though obviously on a much smaller scale and only on your ears rather than your whole body. I don't feel like these tubes change the sound profile of the amp much at all. I don't notice any difference in frequency response or newly emphasized areas of the sound spectrum. They simply take the signature of the amp and make it a little more ballsy. I would say it's pretty similar to what happens when you keep an amp circuit the same but improve the power supply - more juice, firmer grip, better extension, better dynamic range, more palpable sound. In fact, that's a good descriptor for these tubes in the WA2 - they significantly improve the palpability of the music.

Amperex Bugle Boy 6DJ8s - Now, from what I've read, most people feel like the power tubes (the 6AS7G/5998s) should and do make the most difference on the sound of this amp. I respectfully disagree. With the tubes I've tried so far, changing the 6DJ8s definitely made the most difference. Now I don't know if this is because the stock drive tubes are worse than the stock power tubes, or if it just reflects my personal bias towards the characteristics improved by the drive tubes, but to me this was the money spot right here. As I said in my listening impressions, the greatest strength of this amp might be its ability to accurately reproduce tone and texture. Changing to the Bugle Boys took that strength and made it even more obvious. The texture of sound with these tubes in the WA2 is breathtaking. The music just sounds so natural, so realistic. Harmonic detail, the transition of the initial strike of a note to the reverberation of that note within the instrument and then the performance space - these things immediately draw your attention and make you say, "Yes! That is exactly what it should sound like!" Listening to extremely well recorded acoustic music on this amp is so much fun that it must be illegal in the South. I think I will spend the most effort hunting down other tubes to roll in these spots - I can't wait to get my hands on some Siemens 7308s or Amperex PQs. In my own humble opinion, this is the first tube you should roll if you get this amp, and there are tons of choices, many of which are affordable and well-regarded.

Amperex Treble Clef 6V4s - The strength of these tubes is resolution. The first thing I noticed when I rolled them in was their superior ability to transmit low-level detail. Inner voices in orchestral pieces, breath-sounds of singers, the sound of resin-on-string in chamber music - these were all things that became more clear with the new rectifiers. If you have done any photography, you will know what I mean when I say there are pictures that are in focus, and then there are pictures that are IN FOCUS. These tubes are the musical equivalent to nailing that razor-sharp focus on a photograph. They really take advantage of and emphasize the amp's pitch black background, allowing tiny little bits of sound to rise up from nothingness. This is very noticeable with very very low-dynamic music where it is often so difficult to hear detailed textures. With these tubes, moments such as that become highlights of the piece/song/track. It's really something when you combine such low-level resolution with the WA2's tonal accuracy and dynamic range. Don't let anyone tell you rolling the rectifiers in the WA2 won't change anything. It might not leap out at you, but it's there. And it shouldn't be a surprise - look at the WA6. From all reports, the rectifier definitely makes the most difference on the sound, and that's an amp with the power and drive sections combined into one tube per channel.

Keep checking this first post as the thread progresses because I will just come back and add to it for the most part. Let me know if you have any specific questions or picture requests, and I will do my best to oblige. This has been an under-discussed amp, and I would love to help change that.

Thanks again to Jack and family for great service both before and after purchase as well as a truthful timetable and secure packaging. My experience with them could not have been better, and if customer service is important to you, I can't recommend Woo highly enough.

Stay tuned.
Jan 17, 2009 at 6:43 AM Post #2 of 1,751
Nice tube glow. I cant wait to see some high rez internal shots. If you don't mind, take a picture of the rear panel as well.
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Jan 17, 2009 at 3:51 PM Post #3 of 1,751
May the fleas of 1000 camels infest in your hairy armpits!!!

( Its just jealousy, i want a Wa2 dammit!!! )

My fav amp right now. Fine,enjoy your freekin amp already!!!

Jan 17, 2009 at 5:32 PM Post #5 of 1,751
It is remarkably good looking, in ways that really stand out in person. I think it has to do with the perfect scale and proportions of the thing.

And it is a comfort on these frigid nights.

The sound seems to get better minute by minute. I've never been so bowled over by a piece of equipment; it's really opening up my ears.
Jan 17, 2009 at 9:49 PM Post #8 of 1,751
Nice internal shots! Thanks
Jan 17, 2009 at 9:52 PM Post #9 of 1,751
I don't want to say too much yet about the sound since I have only had a few hours listening time so far - but in a word, the amp is excellent with the Grados. From the headphone out of my laptop, the Grados are nearly unlistenable. From the jack on the Benchmark, they are very good phones with some problems that keep them from succeeding with some recordings. From the WA2, they are outstanding. They sound like what you would expect Grado flagships to sound like.

No, if you hate their sound signature, the WA2 won't convince you that they're great phones. But don't doubt for a second what they say about them being extremely source/amp dependent. In fact, I've never heard an audio component so dependent on the rest of the system as the GS1000s. But man, with the right gear, they are damn impressive. They'll never be the best choice for people who just want one pair of phones, and I readily admit that they have their flaws, but none of that seems to bother me when they're on my head...

EDIT: And also, this is with a grand total of about 5 hours on the amp and with the stock tubes. Let's just say I have big expectations for when I start rolling the tubes and the Blackgates start settling in.
Jan 17, 2009 at 10:53 PM Post #11 of 1,751
How warm does the chassis get? BTW, The wiring in your unit looks so much better than the one on Woo's website.
Jan 17, 2009 at 11:57 PM Post #13 of 1,751
That is a beautiful amp

If it sound as good as it looks, you probably gonne be happy
Jan 17, 2009 at 11:59 PM Post #14 of 1,751
I'm totally jealous! I want one in the worst way
Jan 18, 2009 at 12:00 AM Post #15 of 1,751

Originally Posted by atbglenn /img/forum/go_quote.gif
How warm does the chassis get? BTW, The wiring in your unit looks so much better than the one on Woo's website.

The chassis on the WA2 does not get overly warm. In fact no part of the amp does, tubes excepted. A bonus as far as I am concerned.

I agree about the GS1K. The WA2 and GS1K go well together. Some say asthe WA2 is OTL it won't have enough power for the GS1000, wrong. It has plenty.


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