WooAudio WA7 Fireflies


Pros: Very beautiful, great soundstage,
Cons: heavy, inportable, expensive
So just wanted to write this review to say that it makes some weak headphones sound amazing as well!
I just sold my hd800 today. Without it i thought I might as well sell my wa7. However I got this idea to try these wa7 to with my hd598.
This never cross my mind cause the hd598 is too low class for the wa7 i thought. But since I don't have any other headphones to plug into the wa7 with (besides my bose 25 which is a obvious no), i tried it. And it AMAZED ME! My sennheiser hd598 sounds better than then HE400. I don't know if thats still worth it as wa7 is like $1400 (tube power source). But it did made my hd598 go to another whole level (as it did my hd800 as well of course but more noticible on the hd598 actually)
People may disagree but these are purely my opnion :D
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Headphoneus Supremus
Pros: Aesthetics, size, volume control, upgradeable, value
Cons: Not great for rolling tubes, fingerprint-prone
Ah, the WA7 "Fireflies" from Woo Audio. As stunning to behold as it is to hear! This is my first piece of amp/DAC kit that retails for over $1k and well, I'd be lying if I didn't admit that I think you people who spend that kind of dough on these things are only slighly less crazy. 
 Here's why:

The Breakdown:
Test Songs (all ALAC either 16/44 or 24/96):
Limit to Your Love - James Blake - James Blake
What About Me, Kite, Lingus - Snarky Puppy - We Like It Here
Rich Girl, I Want You Back - Lake Street Dive - Fun Machine
The Twilight Zone - Rush - 2112
The Table - Chris Tomlin - Love Ran Red
Make It Mine - Jason Mraz - We Sing, We Dance, We Steal Things
Fugue, from Young Person's Guide to the Orchestra - Benjamin Britten - Simon Rattle and the BPO
MBP running JRMC20 > WA7 + WA7tp* > HE500, RS1i, and T50RP
Sound: Smooth and controlled.
Bass: Thick and punchy. Yes the WA7 is tube-tastic, but that's not to say the low end is a smeary mess. On the contrary, it's quite textured, controlled, and deep. The HE500 low end, which is quite good on it's own, is as enjoyable as I've ever heard it. Kick drums have impact AND decay, and bass guitars are textured and articulate. Check out the crazy subbass on the Blake tune. The WA7 makes my brain vibrate! I should also mention, that with the upgrade Electro-Harmonix tubes in the amp and some GE 5-stars in the power supply, the bass is noticeably deeper, and cleaner. Imagine listening to a beginner attempt to walk a bass line on an 3/4 size upright and then getting to hear a pro play on a full-size. Markedly better all the way around. 

Mids: Rich. Well duh! If you're gonna do tubes, you'd better get the mids right. I'll admit that the WA7 presentation isn't exactly neutral, but in this case, the warmer mids are delicious and a delight to listen to! Any and all vocals (from Lake Street to Rush) sound organic and full. Electric guitars and rock organ are crunchy. Even the growls in the trumpet and sax solos on the Snarky tunes are excellent! Once again, I think I have to mention that the upgrade tubes make a difference here. The EH tubes in the amp are a little warmer than the stock Sovteks. Not mushy or muddy at all. Just a little more forward and more lively. 
Treble: From my Gustard H10 review: "Clean and clear! Just like Windex baby!" The upgrade tubes affect the treble the most (bass is second) and well, the upper end certainly keeps up with the lower frequencies. Cowbells, cymbals, and violins are come through nicely and never sound fuzzy or removed. Now I will say that the treble is not super-extended, but it's definitely not so rolled off that I have ever felt like I'm missing something. It bears mentioning that according to many, substituting a standalone DAC like a Bifrost or Concero can really add some extra detail in the upper end, but like I said before, the treble as-is certainly doesn't want for anything.
Soundstage/Imaging/Separation: Excellent. The 3D-ness of this little silver box is just awesome. In it's stock form, it's certainly above average, but after adding the tube power supply and rolling a few tubes, the imaging this thing generates is just killer. On 'The Young Person's Guide,' instrument separation and placement is just sublime. Even the RS1's with their smallish presentation, are a joy to listen to! This is certainly a main contributor in the enjoyment of this amp.  

Aesthetics/Build Quality/Accessories: Do I really have to expound on the looks? This thing looks like something from Brookstone or the Apple store. Just great. Very healthy weight and clean lines through and through. Plugging in headphones doesn't push it around the desk like the Pan Am used to. Very solid. Also from the Gustard review: "No unneeded text or frills, which if you ask me, is something we should be seeing more of... Nice big volume control[...]" The WA7 looks beautiful on the desk next to the MacBook and I'm quite glad it can back up it's looks with some serious sound!
Qualms: No real qualms, but there are a few things that the potential buyer may want to know. There are limited input options. In a day and age where most new DACs are coming with at least two, if not 4-5 input options, the WA7 doesn't go that far. You can run USB or RCA. That's it. Also, for you tube junkies out there - this ain't gonna satisfy unless you spend the extra $$$ on the tube power supply. The 6C45 is a small family of tube that doesn't offer a lot of variety. This isn't a problem per se, but don't expect to find pages and pages of options if you search for 6C45 tube rolling!
Final Thoughts: I'll spell it out for you: the WA7 is the combo unit to get if you want an all-in-one for under $1k. Add the WA7tp power supply and you've got a setup that rivals plenty of rigs costing upwards of $2000. It looks great, sounds great, and feels great! Like my favorite headphones (RS1s) the WA7 is not the most capable, nor the most revealing, nor the most technical amp/DAC, but I can assure you that it brings a smile to my face every time I power it up! It's just fun! My hat's off to the guys at Woo for making a product that checks off so many boxes.
*Just to be clear, my review was done based largely on my findings using the WA7 with the tube power supply. The stock PSU is quite capable, but I full-heartedly recommend the WA7tp for anyone wanting to get a little closer to an end game setup.
cool I agree the wa7/tp very nice sounding amp..
Good review.  I was also impressed by the sound quality and transparency given its size.  I don't think I'd say it rivals $2000 systems though.
Great, this review definitely sells me upgrading my solid state PSU to a WA7tp. How much is the jump in SQ?


Headphoneus Supremus
Pros: sound quality, build quality, style
Cons: price, dac selection
I have had this unit now for a week and am fully impressed.  Right out of the box and without any burn-in it delivers breathtaking tone to instruments and vocals alike.  Solid power and strong bass drive even with hard to drive headphones.  Switching to some efficient T5p's still leaves the volume pot at 12:00 with a strong performance.  Clearly attention to detail was paid in getting the 1/8 and 1/4 ports matched in volume.  My only complaints being at this price point it would have been nice to have a sabre dac inside instead of a ti compromises slightly the crispness of the signal when used as a dac and it not being able to output as a dac to the rca outputs at the same time as the headphones.  Would have been nice to have a tube pre-amped volume controlled rca out mode. 
After trying one at the recent NYC meet I fel in love with it and bought one right there. It's really sounds great with different headphones but I completely agree that for such price it should have Sabre DAC
Has anyone opened the unit up yet for some photos? Am wondering if the DAC could be later upgraded as I am assuming it is on a separate card probably an off the shelf USB2/DAC as I have seen some companies selling.


New Head-Fier
Pros: Sound quality, silent background, distinct vocal/instrumental separation, size, looks, weight, high/low impedance switch, low fatigue listening.
Cons: Price, no power cord included.
Takes the edge off the Sennheiser HD800's thereby matching up well with them.  Great separation, silent background and low fatigue factor.  Not much to say that hasn't already been said before.  Very nice little tube amp.


100+ Head-Fier
Pros: So gorgeous even the most unsupportive of audiophile wives will allow it in without asking too many questions, sounds as good as it looks, compact.
Cons: Will take up a lot of your "spare time".
Sorry for the late reply, but here we are after day1. I should start by saying that due to working 10am-6pm today, i didnt get as much time with the WA7 as i would have liked although i did get a couple hours in and some very interesting results.

First off, some pics of when i first picked it up from A2A, god it was smaller than i thought!!!!


Next to the ever so tiny Pan Am "portable" amp... almost the same size, in fact apart from a couple mm more of  width, and half a bees bit in length (actually less) = the same size. One thing i did notice is that the 6c45's absolutely DWARFED the little dinky valves in the Pan AM. Build quality and finishes, there was absolutely no competition. Dont get me wrong, i love the sound of the Pan Am, and if it werent for the total package price, id own one (in the end i spent not a huge amount less on the WA7 considering over all cost), but the WOO feels, looks, and is just built better. The volume knob is silky smooth (after the first turn), it does weigh quite a bit though... Which i actually like. It doesnt feel like a chinese guitar pedal with a couple small tubes in it and a MASSIVE sound, it feels like what you expect... A compact american built powerhouse with no expense spared. I also had a chance to see and hold the modi/magni- that thing is also TINY, even smaller than these two, and feels heavy and well built. But the surface finish is no where near the Woo, but rather between the two. Neither rivals had hidden/invisible/no screws, the high end feel, nor design. But then again the Schiit offering is a third the price or less than a quater if you bought after the WA7 pre release. Respectable, but not in the same league, and not even tube driven- just a size and finish comparison as it was there at the time. I will go back to listen to it though as it had me intrigued as to what can be achieved with a small retail of $300 or whatever (Aus delivered with power supply, not supplied by Shiit but sourced in the same factory).

First listen was VERY brief. Buena Vista Social Club and Grado GS1000i, I could think of worse ways to start my day.

Even with these cans, this thing packed a punch. Not fully warmed up, DAC in play (had to load the driver on the PC there), and 12 o clock was verging on too loud with the big Grados. 

Thats the well built Power supply behind it, side by side its bigger than the amp in some dimensions!

Home sweet home and in business. Fully warm, and mated with Fischer Audios finest cans to date, FA002W Karelian Birch, with the non high edition drivers fitted because i like a fat deep reaching sound, and DT770 250. Via my macbook pro it was seamless at first. No driver. Select the audio input "speaker" and away i went. I used some 24 bit files FLAC and ALAC both through itunes and VLC (same tracks) and it sounded pretty darn good! But I noticed immediately that it wasnt reaching as low as id like on my usual test tracks that had gooch wrenching sub bass... whats going on? CCK (Camera Connection Kit) and ipad, same tracks- deeper sound, the sound i expected!!! GOD ITS NICE. This thing (on both devices with both the DT770 250 ohm, and FA002W 64ohm drivers) is a POWERHOUSE. 11 o clock is LOUD, im a volume fiend, but try as i might i couldnt get it much past 11 without fearing i might burst an ear drum. My teeth were grit hard at 11 and a touch (cant get past there), my brain was buzzing with bass vibration, while the high end sizzle and pops of trentemoller, radiohead, and dabrye made my sparse body hairs stand at attention. Its was the physical satisfaction you hope to expect from "the seriously good gear" at the highest possible volume you can bear. Win.

But wait, what happened with the macbook? Re-test. I didnt imagine it, its not as good? What is the ipad doing that the macbook is not? At first i assumed that i was listening to the proprietary DAC of the ipad (like an iphone would do) and that the "32 bit mac native" WOO DAC was rubbish. Then after calling a friend, we realised i was using a CCK, which means (with most amps) I should be using the WOO DAC. Then it hit us- I was so excited about all this "Mac native" stuff I didnt change the midi settings. I was listening to 16 bit on the Mac, and im guessing 24 bit on the ipad (the reason i recon its not 32 bit on the ipad is because the somgs were IDENTICAL, even with the same graphic EQ once i changed the mac to 24 bit. That being said the songs were only 24 bit recordings so who knows... Anyone got some 32 bit test tracks?

Anywoo, I was impressed  i was in bliss, this thing SERIOUSLY delivered. It doesnt sound anything like a WA6, but weirdly closer to the Pan AM, only a little more detailed and less 'fun'...It wasnt so tubey and glossy like a vaseline lubed wide lens in 80's porn set lighting, like you would expect from some tube amps, but it wasnt as icy cold and unforgiving like you expect from reference grade solid state big hitters. Was it in between? Nope, this was no hybrid amp sound. This is hard to describe. Let me try in more depth. The Woo reaches DEEP, and is POWERFUL. Its everything you want it to be and just a tad more- because its so damn sexy you feel like you stole it from the future somehow. I liked the Pan Am a LOT, its signature suits me. It has a deep sound, and trumped even the WA6 at bass, not to mention absolutely slaughtering the Schiit Valhalla in almost any respect. But what it did best, was electronica. It has a fun signature, with crisp highs, and low bass- a mostly flat smiley. I was in love with it. WAS.

My biggest fear is that the WA7 would look the business, but fall short in terms of the actual overall sound-joy i got from the Pan AM. This isnt me justifying spending more here, it cant be, i spent less. The sound, without doubt, nor the need for multiple back n forth a/b'ing the same tracks, is quite obviously better. Its similar, very similar in what it does, it just god damn does it better! I could punch myself in the face at this point. What kind of woodoo has Jack come up with? Has he done a deal with the audio devil? Yes im excited about my new gear, but im not excited because its new, I bought several new toys at once, and they are all nice in their own way, but this is the first and only one to meet all my hopes and expectations. I wont say it surpassed them, because I have listened to a lot of amps and cans by now, and i kinda knew what to expect. I wasnt comparing this thing to a fiio e10 (not that theres anything wrong with an e10), nor a NAD home theater integrated amp. I was hoping that this would be be as good as it looks, and it is... Seriously. Its a GREAT great great amp, and i would pay for it again, and again if i had to. I dont think ill ever feel the urge to buy another home amp. Dont not buy one of these amps idiot.

Every time i left the room to play with my daughter or help out with dinner, i found myself leaning back in to glance into the lounge to make sure i still owned it, and it was real.

Stay tuned for the tube rolling guide as i have 3 other (2 NOS, 1 EH gold pin) sets of tubes!!! DAC only tests to come too when i figure out how to use all 32 bits?
(for some reason spacing gets gnarly from here on, im guessing its from adding too many edits to one post? mods are welcome to interfere).
EDIT: part 2, day 3,


T50RP & WA7

Spent a night with these two bad boys.

**spoiler alert; i still prefer the Fischer Audio FA002W**

But thats a GOOD thing, why? Because what ive found more than anything [to my delight], is that so far a particular set of cans through the WA7 will sound just like that particular cans... Perhaps obvious, but not always true to other amps, and EXCELLENT news for me. So comparing the DT770 250 OHM, the FIscher FA002W, and T50RP (hardest to drive so far, got them albeit uncomfortably to 2:00), they all sounded like themselves, they all rang true. Im now starting to get more of a feel for this amp. Its really quite good, and the beauty is in its simplicity- both of design and (as i said in my earlier review post) tonality. This doesnt just sound as good as it looks, oddly enough it sounds just LIKE it looks. 

Let me explain. The physical design of this new woo to my eyes is smooth, classy, clean, but expensive and beautiful, a large portion but not all of it is also transparent (glass). Most importantly, its also very linear with only 3 prominent features:  two central glowing tubes, and a big volume knob. Once you hear this amp a few times with different cans over a few days, ALL of these physical attributes read as a genius review, a descriptive of the audible characteristics. It's an awe inspiring design, and an absolutely amazing interpretation of the sound.



EDIT: part 3 day 3,

So this just arrived in the mail:


Im guessing by the label its my NOS russian (Reflektor) matched tubes i ordered from ebay. Item number; 140906991405

"STRONG MATCHED PAIR 6S45P-E = WE437 LONG LIFE Triode Tubes, NOS, OTK, Reflektor"

Who puts stickers on tubes? bit of electrical cleaner, and a long polish with a clean microfiber, and they were ready to burn in!

Top is the stock Sovtek, bottom is the Reflector 6S45P-E/WE437 clone. Bit of a funny angle, but they are actually the same size/shape- different stamping that didnt pick up in this shot.

Burn in at this stage was minimal, but results were not.

Its not easy to fluidly explain this situation without sounding like an overly enthusiastic techno-fanboy with a new toy, raving and ranting about audio-castles in the sky. I want to be able to say, "oh well, it was only a $38 experiment in the uncharted waters of WA7 tube rolling. An educational and worthwhile exercise, but non the less the stock tubes are better *enter descriptives here*". Unfortunately/fortunately i cant do that. Chalk it down to whatever you like, the first (of three) pair of matched tubes to hit my door step, ordered the same day as ordering the amp itself a month ago, are absolute brutes!

Many are of the opinion that the amp makes the tubes and not the other way round, and i certainly agree here. So I'm not going to tell you these tubes will suddenly induce the WA7 to metamorphosis, emerging from the fog as unicorn with a glowing vacuum horn and two optional inputs under its tail (one apparently more sensitive... for IEM's). What i am going to say is this:

The Reflector 6S45P-E will significantly liven the mid range, very significantly enrich the bass (biggest change), and ever so slightly warm the highs (very minor change here). That being said, it still sounds like the WA7. All of my above notes and comments still stand "smooth", "classy", "clean", "beautiful", etc, etc. Perplexing as it may seem i guess the best way to describe it is mood. Same dude, different mood. Like using a "sports setting" on your automatic car. Same car, different feel. I personally really enjoyed the change, and doubt i will go back to the stock tubes. If your a jazz/classical listener you mayfavor the stock flavour for those genres. For rock, metal, electronica, and hiphop the "Other Russians" take over, and boldly so. 

As always ill keep you up to date with any changes or impressions... And on any more tubes arriving.

I also had a major crisis tonight that was likely my computers fault, but i played around with the midi setup, and quite a lot. I harassed it, flicking back n forth from 16-24 bit, through all the hz ranges. Violently defiling my poor MBP, until something finally gave. The WA7 started to add distortion on lower frequencies, quiet patches were not quiet. then it just stopped. Plugged, replugged, try the other USB port, tried closing and reopening programs, reset, and still nothing, then it just worked? go figure. I hope it wasnt the WOO, im pretty sure it was the macbook, we're friends n all but we sorta arent.





EDIT: part 4 day 4,

Electro Harmonix 6C45Pi GOldpins arrived last night. Stay tuned!

ALSO after emailing Jack regarding tubes, as we all suspected this was the reply the kindly sent:

"[size=11pt]Hi Adrian,[/size]

[size=11pt]The 6C45 is a very special tube. There is no other types can be used. Though WE437 is a direct substitute. This tube is very rare, however.[/size]




So as far as i can tell without too much effort, 6c45pi from sovtek (current production?) or EH (current production) /6s45P-E (same thing just one is krylic for the other, and the E is military) from Reflektor (NOS), and if you want to spend more on tubes than you did on the amp you can get the WE437 from Western Electric... No idea what kind of difference it would make? 


One other candidate im interested in is the 6S15p/6C15Pi, this is the same on paper to the 6c45P, and according to two online sources could be rumoured to be the vintage consumer (non military) version of the NOS Reflektor. Cant even find them though.

EHX 6C45Pi Gold pins.

So they are finally here! I was very enthusiastic about trying these out. I figured the Woo Crew wouldnt have offered a second tube upgrade option if they didnt yield results in testing. I obviously cant comment on Woo's testing (perhaps Jack can?) but in my own experience I certainly found that there was indeed a difference. The amp, although still essentially the same had new perspective, at first apart from some extra depth on the bottom end (more so than the reflektor), and having to adjust the volume slightly down, the change seemed rather minor. Then i went back to Reflektors and felt instantly unimpressed by them, the same tubes i praised yesterday? you bet. I let them burn longer.
More testing the same 10 tracks then, after waiting for some cooling off, i changed back to the Gold Pins.

[This in itself is a problem that faces all of us when actively reviewing tubes on the same single unit. Cooling times and then the subsequent warming times dont allow for an instant A/B. The solution, two WA7, and two sets of Fischer fa002w karelian birch woodies. DOnt get excited, this unfortunately (for now) just isnt an option. UNLESS someone in Melbourne with a WA7 wants to meet for a side by side comparison- i can easily arrange two bran new identical headphones, say DT880 or something? ]

After the cool/warm time, and hoping my brain had established a lasting sonic image of the Reflektors through the last 8-12 hours or so of intermittent listening over 24 hours, i settled in for second session with the EH goldies.

They are a sure improvement, a stark change. Again, not a new amp- but with further reach. Most will greatly praise the extension and sparkle these tubes add to the upper end, while others will either love or hate the extension it adds down below. For me, this is exactly what i was looking for. The difference was akin to hitting the +8db peak bass boost switch on a C421. Perhaps for those who dont own or havent heard the C421 (soon to be replaced by the exciting new JDS labs C5), this would likely mean nothing. To those people I would best describe the lower end endowment added by the gold pins as "awesome". This isnt a flat signature. With the Gold Pin EHX in place, this definitely isnt an amp for referencing, and who would want it to be when this amp sounds SO GOOD! This is how i want my music to sound, this is how my WOO WA7 will stay. For referencing actual enjoyment, use a WA7 with Electro Harmonix 6C45Pi.

This amp sounds very nice in stock form, im a big fan of it compared to the Pan Am (its closest competitor) also in stock form. As with most things audio, and often life in general, you never really notice how much better things are until you view them in retrospect. The ears and brain (at least mine), always seem to appreciate a nice improvement, but its not till you go back to what was, when the differences really become apparent.
In summery if your going to spend $999 on a gorgeous little amp, spend $60-$100 more on some tested & matched gold pins.

I havent yet tested the gold pins against raw stock, however im certain Jack has. After the time spent with both the Reflektors and the Gold Pins, i can honestly say that these are obviously offered by the manufacturer with a good reason.

Dont bother with the Reflektors, go straight for these.

For now, thats all from me. Ill be back in a week or two with more if anything comes to mind. Questions and comments are of course always welcome! 

Very comprehensive and informative review, so thank you for a sterling effort. My WA7 is on order and I'm eagerly anticipating it's arrival.
Can you arrange me some brand new identical headphones -- for free? Lmao great review and great read.
I agree that old 6s45p sound fuller than new production. 
Pros: Good DAC. Small form factor. Beautiful. Dead silent background. Great with IEMs. Plenty of power for orthos. Good for all cans. DAC works w/power off.
Cons: Only one optional set of tubes.

A Tale of Two Tube Amps​

Woo Audio WA7 and ALO Audio PanAm​


My normal gear preference and choice for many years has been solid state. I have held a curiosity, however, in tube-based audio gear and the possibilities and presentation that comes from it. It might be considered ironic that considering how endlessly I have been fiddling with my main system for years now that I wouldn't consider an amp that would allow me to do this considerably more via tube rolling, but my indecisiveness has intervened more often than not, especially when presented with too many options. 
Likewise, many people, when seeking suitable audio equipment to buy, simply want an answer to seeking good sound, without the complexity and fuss that that us enthusiasts tend to dabble in. So given my interest in exploring tube amps and the recent interest in both the PanAm and the WA7, I arranged to have both sent to me. As an exercise in something a little different to the norm, I'm going to review them together.
I'd wager that if you asked the average Head-Fier whom they thought of when tube headphone amps are concerned, they'd say Woo Audio. Jack Woo and family's stable of amps, from the WA-2 through to WA-6 and variations have been the go-to for many seeking a well-built amp to fit their budget. The WA6 I'd say has pretty much become a standard for tube amps on Head-Fi. Lately, however, they have been expanding into new and interesting directions with a CD transport and DAC and the latest of their amps, the WA7 which, unusually, includes a USB input.
The story behind the WA7 is, basically, that Jack wanted to design something for the ordinary person, with a good aesthetic, compared to his usual offerings which come across more for enthusiasts. Seeking an appealing design, he asked the best person in the world for advice about the shape it should be: His wife.  "A cube" she replied and thus that is what the WA7 became. However, as the WA7 has transformers for the headphone outputs inside, taking up quite a bit of space, something was going to have to give and thus the power supply is external, connected via an umbilical. To complete the picture, the box itself has no visible screws, those having been banished to underneath the amp. Likewise, connections and controls other than the headphone sockets and volume are at the back. The result, for $999 is a unit with the simplicity and neatness of something I would more imagine seeing on the shelves of an up-market home-wares store than in my local hi-fi store.
The PanAm stack next to a Leckerton UHA-6MKII.​
ALO Audio's PanAm too was the result of a particular idea -- customer requests for a desktop amp under $1k, though in this case, considerably below it with the basic configuration starting at $499. While in the past Ken has been associated mostly with cables, more recently he has entered very solidly into the portable amp market with the RX, National, Continental and now International amps. The PanAm resembles a larger version of the Continental with regular tubes as opposed to the small "hearing aid" tubes in the portable. Like the WA7, it has a separate power supply, but this is where things get interesting. The basic amp comes with a regular wall wart but can optionally be paired with two different power supplies, each in a box the same size as the amp itself. The first is The Gateway, a wall-powered unit containing a better power supply than the wall wart, improving the sound. The second is The Passport, which contains a battery. Three lengths of neat, right-angle-plug umbilical cords come with either so you can arrange them neatly beside or atop each other.
This gives the PanAm an unusual calling: As well as being able to act as a desktop amp, it is also a light-weight battery-powered transportable amp. It too contains a USB input and, thus, DAC, cased in well-made, somewhat industrial-looking brushed aluminium. It is attractive more so being small and neat, the amp itself sitting neatly atop the Passport and/or Gateway. The amp comes with stick-on feet but my feeling is to also add a couple of small pieces of velcro on top and under the various units as required to help them stay together, such is their lightness. Large rubber bands will do this too, though that doesn't look as neat. Bought together with either the Gateway or Passport the PanAm becomes $569 and $639 respectively or $749 for the full kit (before extra tubes).
The WA7 in comparison is heavy, not only sporting two custom transformers between the tube output and the headphones but a block of glass -- yes, that really is glass around the tubes. Jack Woo took the aesthetic angle even further and went to a huge amount of trouble to get the blocks made. Opening the box, which was quite heavy with the power supply, one of the first items I spotted was a polishing cloth.  The manual cautions about placing the glass on carefully -- straight down around the tubes and not at any angles in any direction. With good rubber feet underneath, the amp doesn't move anywhere when headphones are inserted or removed.
The PanAm is deceptively small. For some reason, whenever I saw the pictures, I imagined it to be larger than it really is. The 1/4" headphone socket on the front and RCA sockets give it away though. So too are the Gateway and Passport. While the weight adds up with all three units together, any two together aren't particularly heavy and I could very realistically consider taking them with me when travelling. In fact, the whole kit would fit nicely into my Reddox Gator, along with my 11" MacBook Air with room for a good-sized pair of headphones and other gear. For this purpose ALO Audio will include a special carrying case.
Bringing our attention to the rear of both amps reveals a similar set of connections, with a couple of small, but significant differences. The PanAm has a mini-plug input, not a surprise considering it is intended to be (trans)portable and a mini-to-mini (or mini to dock connector) is the most convenient cable to use with an iDevice or DAP when out and about. However, while the PanAm's RCA connections are only for input, the WA7's can be used as either an input or a line output from the DAC.
Indeed, that is one of the neat features of the WA7: The USB DAC works even when the amp is switched off. It powers, unlike the amp, from USB directly and the output does not go through the tube amp at all. The positive of this is that, say, one could use it with powered speakers during the day, then switch on the amp at night for use with headphones. I can readily do this with my ADAM ARTist 3 speakers, as they have a linked volume control feature this is perfect for.
I could readily use the PanAm as a pre-amp, but that requires use of the front headphone sockets. Conveniently my ARTist 3s have a front input, so I tried it with a mini-to-mini cable with good results.  The WA7, likewise sounds good as a DAC.  Being USB-powered, the WA7's DAC can be improved upon to a degree with a better USB power supply system (such as an Aurorasound USB Bus Power Pro, Vaunix USB hub or the like). While I'm usually fairly picky about the quality of digital components, I feel satisfied enough with the quality of the DACs in both the WA7 and PanAm that I don't feel the need to dissect the sound of each nor felt a desire to use one of my high-end external DACs with either. More notable for the PanAm considering its transportable pretensions, the DACs in both amps fare far better than I've experienced in portable amps with the exception of the most expensive ones, such as the Fostex HP-P1 and CLAS. 
In practical terms, however, if you are like me and some of your music is higher-than-CD-quality from Linn Records, HDTracks and other places and you'll be using a computer as a digital source for either amp, some attention to the capabilities of the USB inputs will need to be paid. The PanAm's Tenor chip will accept 44.1 (CD quality), 48 and 96 kHz input, but not 88.2.  The WA7's CMedia USB higher and accepts 44.1, 48, 96 and 192 but not 176 kHz. [Note: Jack informed me 176k was supposed to be available and is investigating why it isn't.] If you have high-res music with a variety of bit rates, you'd do well to have software that can match the output bit rate suitable as well as re-sample on the fly if required.
Also worth noting is, while the PanAm shows up in my Mac's Sound preferences as "ALO Audio" the WA7 showed up as a bunch of inputs and outputs. The "Speaker" output is the correct one to select, the others having no function. However, I imagine many people choosing the PanAm will be using it like I did with the Passport and a portable source such as an iPhone where this isn't an issue.

The Amp Sections


I wanted to get into describing the sound of each amp but to do that requires some understanding of how each amp is set up to drive headphones.  
The WA7's blurb states that no semiconductors are used in the signal path, though this refers to the amplification section, not the DAC. As the output of tubes alone isn't entirely suited to driving a wide variety of headphones, custom made transformers are used instead. A switch on the back is included allowing selection of "High-Z" or "Low-Z" headphones -- high for 70 Ohms and above and low for any headphones, but especially IEMs. The WA7 is the first desktop amp I've encountered with a socket specifically for IEMs and is designed electronically to match. Jack emphasised this point and that the amp is completely silent. Indeed, plugging in a pair of RE-ZEROs which are fairly sensitive and turning the volume all the way up (without music playing)  there was not the slightest noise to be heard.
The PanAm on the other hand is a hybrid amp, the ultimate output via a solid state circuit. It too has two output sockets with a gain switch next to the volume control. Again, testing with the RE-ZEROs I was presented a dead silent background, even on high gain. The only sound I could hear was the result of noise passed through the tubes as a result of touching the amp.
While Woo Audio's usual offerings facilitate using a selection of tubes, allowing the enthusiast considerable entertainment in attuning the amp to one's headphones and tastes (and the possibility of spending considerable money on new-old-stock tubes) the WA7 is unique in that the stock tube is pretty much the only one available in its type. On offer is a single, $100 upgrade by way of a pair of Electro Harmonix Gold Pin tubes in limited quantity.  The PanAm on the other hand uses tubes for which there are many and varied varieties available, very often for cheap, both from ALO and elsewhere. Thus while the WA7 is focussed on plug-it-in, listen and enjoy, the PanAm facilitates the enthusiast's enjoyment of tweaking.
One might ask here: Why tubes at all? Especially so with the PanAm, which, with the tubes sticking out perpendicular to the lay of its container, ends up interfering with its own portable pretensions. The answer is: Why not? The reasons for using tubes in an amp range from the preferences of their harmonics to certain benefits they have over solid state components and, not to mention, the almost limitless tweaking. They also look cool and their aesthetic is only emphasised by the design of both amps.
However, while the WA7's limitation is that it is not a tube-roller's amp, the less expensive PanAm, with its option of battery power has something of a limitation when it comes to power and headphone drive. While with my LCD-3s I can turn the WA7 up to ear-bleeding levels without them distorting, try such a thing on high gain with the PanAm and the amp distorts. That loud I didn't try with the headphones on my head, of course, and I doubt anyone could listen at that level without their hearing being rapidly destroy. Regardless, it emphasises the difference between both amps.
In real listening terms, at the levels I listen at (70-90dB before peaks) it only becomes a potential issue with the PanAm if I break out big orchestral works listening with LCD-3s and turn the volume right up, at which point there is some audible compression (ie: the sounds start to blur altogether). For most listening I did the PanAm surprised me by capably delivering a lively and good rendition of all that I usually listen to, despite its physically insubstantial size and I very much enjoyed listening with it. Even with the PanAm on battery power, for most of the music I like, it still sounded great and didn't fail to deliver. The tubes only get moderately warm in the PanAm -- I could still touch them after it had been on an hour with the Gateway. Using the Passport as the power supply instead they were yet less warm, suggesting they are drawing less power.
That being said, the PanAm's stock tubes, while they sound good out of the box, have some shortcomings. Especially with my 300 Ohm MB Quarts the bass was wooly and the treble a little harsh. Thankfully it is possible to upgrade to better tubes for as little as $9/pair for the Russian Voshkods.  Given how much tighter the bass was and how much better the soundstage, mids and treble are with some of the tubes I'm going to consider a tube upgrade as part of the kit in the same way the Gateway is if you want the best results from it.
Of the upgrade tubes for the PanAm, my feeling was the Voshkod 6HZ1V-EPs are the most lively and spacious, the Siemens similar but with a bit flatter and less dynamic sound and the Mullards CV4010s the best balance between the sweetness of tubes and the detail and liveliness of the Voshkods. 
The PanAm with Mullard tubes.​
The WA7 gave me an initial impression of being somewhat mellow, the stock tubes emphasising the bass and de-emphasising the treble while delivering enjoyably syrupy vocals and instruments through the mid-range. The analogy that came to mind was of listening to music while relaxing in front of the fireplace (or maybe it should be relaxing in front of the pretty glowing tubes). It gives vocals the kind of warmth that wants to seduce you with the music more than point out every little detail and makes listening very relaxing. For example, the saxophone, harmonica and piano on Jean-Pierre Mas' (H)ombre seemed to be brought forward, yet at the same time given some warmth.  It did this while keeping a believable soundstage to the music. The presentation was so enjoyable that I had to stop writing to listen to Solamente Dos Veces in its entirety. If there is a downside to this, it's that the focus on the vocals and main instruments sacrifices the micro-detail, more of which I wish was audible. For that upgrading to the Electro Harmonix Gold Pin tubes will be necessary.
Though to some degree I adapted to the sound, I felt that the WA7 lost a little of its wooly-ness after having been run for a few days, the bass becoming less boomy than I felt it was at first. I left it on during the day to speed up any changes that might come about from use. Level matched with pink noise to the PanAm, the difference in drive felt like the difference from switching from a 2-litre hatchback to a big V8 sedan, the power being more effortless and my feeling moving more towards wanting to just listen to the music (and so it should, given that, depending on configuration it costs almost double the price). In fact, the degree to which both amps succeed in bringing enjoyment to the music was such that I didn't switch my main system on for some days but just used both amps to listen instead.
Appreciable about the WA7 was that whatever headphones or IEMs I used with it, the performance was consistent. Even with the Sony XBA-3s which, due to their wacky impedance, which goes as high as 90 Ohms in the treble which can trip up many amps, there were no issues, the music delivered cleanly and clearly.
Switching to the Electro Harmonix Gold Pin tubes and the WA7 becomes less "tube" like with the treble more open. This matched well for me with my LCD-3s but owners of brighter headphones might prefer the sound with the stock tubes. What wasn't lost was the lovely presentation through the mid-range and the sheer enjoyment of listening.
Likewise the PanAm. What struck me about the Continental the first time I tried it was how pleasant it was to listen to music through it, even with my iPod or iPhone as a source. The PanAm expands on that while optionally being transportable when purchased with the Passport power supply. It's main benefit is more power than a portable amp for driving full-sized headphones. With my tricky Sony XBA-3s it wasn't so happy, resulting in a bright and thin sound. However, relatively inexpensive IEMs are not what the PanAm is for. As I was writing this review, Anakchan suggested to me that what I needed was a pair of Ultrasone Signature Pros, as they are closed-back but good-quality headphones that are easy to drive. These would likely be spot on with the PanAm for a "bag rig" to take to a cafe or library.

In the end...

Both amps take up little desk space and don't require much to get started beyond a USB cable, (or a cable to connect your existing iDevice, CD player or the like) and some good music. If you're after a simple buying decision for a desktop amp and it's within your budget, get the WA7 at $999 (or $1099 with the EH Gold Pin tubes) and consider yourself done. If you want to be able to take the amp to and from work (or the library!) with a pair of full-sized headphones then get a PanAm kit ($499-749 depending on options selected, plus extra tubes). Both will work well with all full-sized headphones (possibly excepting the HE-6) and for a few hundred dollars extra (or close to double the price depending on the configuration) the WA7 gives you plenty of power for almost all headphones, 192k USB input and is great with IEMs too, if not transportability. 
Should I buy this amp? Here is a summary of the pros and cons of each:






  1. Small, attractive form factor that doesn't take up much desk space.
  2. All-in-one DAC and amp.
  3. Dedicated IEM port.
  4. Drives most all headphones, no worrying about matching your headphones or IEMs to the amp.
  5. Good USB DAC that works with the amp switched off.
  6. Dead silent background.
  7. 192k high-res USB input.


  1. Small and attractive design.
  2. Light and transportable.
  3. Flexible with a choice of power supplies.
  4. Good USB DAC.
  5. Drives full-size headphones reasonably well, even orthos.
  6. Tube rolling options are cheap.
  7. Power usage is low.
  8. 96k USB input.


  1. Not transportable. Firmly for your desktop.
  2. No tube rolling unless you want to pay extortionate prices from eBay sellers.
  3. Glass cover invites OCD-like polishing.


  1. Not so great with IEMs.
  2. Stock tubes are a bit lack-luster (though an upgrade is only $9).
  3. Ultimate power is limited. 

Thanks to Ken Ball and Jack Woo for lending me these amps for review.

Headphones used:
Audeze LCD-3
Symphones Magnums
MB Quart QP 400 (bright, high impedance headphones)
Sony XBA-3

September 2013 update: Here's a video review:


Headphoneus Supremus
Pros: Beautiful amp Beautiful sound
Cons: Price
A truly stunning aesthetic combined with a high level of functionality and a beautiful sound suggests the Wa7 will be around for a while.
Purists may be turned off by the internal USB powered dac , LED enhanced tube glow and the lack of rolling options.
I think this unit will really appeal to people who may have been interested in a tube amp but worried about the potential problems.
The Wa7 is a set and forget solution just plug in switch on and relax.
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Reactions: BirdManOfCT
Great review Domatrix, many thanks- loved it.
Where did you find it for 899?
Pre-order price for early birds got the black glass version too