REVIEW: Woo Audio WA7 Fireflies Tube Amp

Review by Guest Author: Adrian Weinberg

UPDATED: Here we are after day 1. I should start by saying that due to working 10am-6pm today, I didnt get as much time with the Woo Audio WA7 Fireflies 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!!!!

Woo Audio WA7 Fireflies 1

Woo Audio WA7 Fireflies 1

Next to the ever so tiny Pan Am “portable” amp … almost the same size. In fact, apart from a couple mm more in 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. Don’t get me wrong, I love the sound of the Pan Am. And if it werent for the total package price, I’d 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 doesn’t feel like a chinese guitar pedal with a couple small tubes in it. 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 $200-$290 or whatever.

Woo Audio WA7 Fireflies 2

Woo Audio WA7 Fireflies 2

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 drivers on the PC still), and 12 o’ clock was verging on too loud with the big Grados.

That’s the well built power supply behind it, side by side its bigger than the amp in some dimensions!

Woo Audio WA7 Fireflies 3

Woo Audio WA7 Fireflies 3

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 wasn’t reaching as low as id like on my usual test tracks that had gooch wrenching sub bass… what’s going on? CCK (Camera Connection Kit) and iPad, same tracks … deeper sound, the sound I expected!!! GOD IT’S NICE. This thing (on both devices with both the DT770 250 ohm, and FA002W 64ohm drivers) is a POWERHOUSE. 11 o’ clock is LOUD, I’m a volume fiend. But try as I might, I couldn’t get it much past 11 without fearing I might burst an ear drum. My teeth were grit hard at 11 and a touch (can’t 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. It 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 Pro? Re-test. I didn’t imagine it … it’s not as good? What is the iPad doing that the Macbook Pro 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 realized 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 didn’t change the midi settings. I was listening to 16-bit on the Mac, and im guessing 24-bit on the iPad (the reason I reckon it’s not 32-bit on the iPad is because the songs 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 doesn’t sound anything like a WA6, but weirdly closer to the Pan AM, only a little more detailed and less ‘fun’… it wasn’t so tubey and glossy like a vaseline lubed wide lens in 80s porn set lighting, like you would expect from some tube amps, but it wasn’t 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. It’s everything you want it to be and just a tad more … because it’s 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 all respects. But what it did best … 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 Fireflies would look the business, but fall short in terms of the actual overall sound-joy I got from the Pan AM. This isn’t 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. It’s 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 I’m excited about my new gear, but I’m 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 won’t 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 wasn’t comparing this thing to a fiio e10 (not that there’s 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. It’s a GREAT great great amp, and I would pay for it again and again if I had to. I don’t think I’ll ever feel the urge to buy another home amp. Don’t not buy one of these amps!!!

Woo Audio WA7 Fireflies 4

Woo Audio WA7 Fireflies 4

Woo Audio WA7 Fireflies 5

Woo Audio WA7 Fireflies 5

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.

Woo Audio WA7 Fireflies 6

Woo Audio WA7 Fireflies 6

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?

EDIT: part 2, day 3,

T50RP & WA7

Woo Audio WA7 Fireflies 7

Woo Audio WA7 Fireflies 7

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 I’ve found more than anything [to my delight], is that so far a particular set of cans through the WA7 will sound just like those 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. I’m 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 doesn’t 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, it’s 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:

Woo Audio WA7 Fireflies 8

Woo Audio WA7 Fireflies 8

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”

Woo Audio WA7 Fireflies 8

Woo Audio WA7 Fireflies 8

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

Woo Audio WA7 Fireflies 9

Woo Audio WA7 Fireflies 9

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 didn’t pick up in this shot.

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

It’s 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 nonetheless the stock tubes are better *enter descriptives here*”. Unfortunately/fortunately I can’t 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 you’re a jazz/classical listener you may favor the stock flavour for those genres. For rock, metal, electronica, and hiphop the “Other Russians” take over, and boldly so.

As always I’ll 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 computer’s 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 aren’t.

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:

“Hi Adrian,

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.

Thanks,
Jack”

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. Can’t even find them though.

EHX 6C45Pi Gold pins.

Woo Audio WA7 Fireflies 10

Woo Audio WA7 Fireflies 10

So they are finally here! I was very enthusiastic about trying these out. I figured the Woo Crew wouldn’t have offered a second tube upgrade option if they didn’t yield results in testing. I obviously can’t 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 don't allow for an instant A/B. The solution, two WA7, and two sets of Fischer fa002w karelian birch woodies. Don't get excited, this unfortunately (for now) just isn't an option. UNLESS someone in Melbourne with a WA7 wants to meet for a side by side comparison - I can easily arrange two brand 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 don’t 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 isn’t 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, I’m 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 it’s not until you go back to what was, when the differences really become apparent. In summary if you are going to spend $999 on a gorgeous little amp, spend $60-$100 more on some tested & matched gold pins.

I haven’t yet tested the gold pins against raw stock, however I’m 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 for a good reason.

Don’t bother with the Reflektors, go straight for these.

Woo Audio WA7 Fireflies 11

Woo Audio WA7 Fireflies 11

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

Adrian Weinberg
http://www.exoticaquatic.com.au

Latest posts by Adrian (see all)

  • Spencer Edgington

    Spectacular review!!! I have to get one of those …

  • Jon Mentor

    I have one on order but they are saying it won’t ship until mid-march. After reading this review, I can hardly wait!

  • Zuzu Gates

    Sexy

  • Jill Binoche

    I thought you said it was only $799?

    • Adrian Weinberg

      That was the introductory price I paid, which was available on preorder for around 4-8 weeks. Its now at the intended retail. Still a great buy when compared to its closest competitors in that price range.

    • Jon Mentor

      I got in just before they raised the price to $999 … $799 was an introductory special offer.

  • Ping Jintao

    Can’t wait for mine ;-)

  • Adrian Weinberg

    Worth every penny, which lets face it, isnt easy to say these days.
    The original review is a work in progress and now, after receiving a package from Russia with love, i have the a brief foray into tube rolling the WA7 up. More tubes are en route.

    • Ping Jintao

      Great review. Are you going to try it with the Electro Harmonix tubes that Woo sells as an upgrade?

      • Adrian Weinberg

        Sure am! THey are well on their way by now, and should be here any day.

        • Ping Jintao

          Excellent! I was waiting to order the upgrades until I read some reviews.

          • Adrian Weinberg

            Actually i bought my matched EHX from ebay for $60 posted. The extra $40 may be worth it for some to have piece of mind that they come tested by WOO. I do know however due to the massive influx of orders, the latest orders are shipping late March. I assume tubes would ship earlier, but that would depend on just how busy they are?

        • Jon Mentor

          Cool – I too am anxious to read your review of the EH tubes. $100 actually isn’t a bad price for a matched pair pre approved by WOO.

          • Adrian Weinberg

            Actually i bought my matched EHX from ebay for $60 posted. The extra $40 may be worth it for some to have piece of mind that they come tested by WOO. I do know however due to the massive influx of orders, the latest orders are shipping late March. I assume tubes would ship earlier, but that would depend on just how busy they are?

          • Ping Jintao

            I have a feeling they are a bit swamped this week.

  • Adrian Weinberg

    I just got my pair of EH gold pin 6C45Pi in the mail! Ill keep you guys posted. So far the Reflektor tubes were also great. A fiar bit warmer on the bottom end, but for rock, hiphop, and electronica i LOVED them! Theres more detail in the original headfi review which is growing rapidly. Not sure i could copy and paste it here especially with all the pics and what not.

    • http://www.humanovation.com/ Jon Mentor

      How do they sound? Worth the upgrade?

    • Ping Jintao

      Waiting anxiously by my monitor for your updated review rollin’ the EH tubes ;-)

  • Adrian Weinberg

    Hey guys! Gold Pins tested extensively and added to the initial review. Feel free to copy here if you like.

    • Ping Jintao

      EXCELLENT! I just ordered the EH tubes . Like you say, if you are going to spend that much on the amp, spend the extra $100 and get the right tubes. Thanks for the suggestion and your review!

      • Adrian Weinberg

        good choice, mine will be staying permanently attached. Again the difference isnt night and day (still a WA7), but it is an obvious and undeniable extension in both upper and lower region, resulting in a far more satisfying sound. I thought it was fantastic stock, but this set up is magic. (verging one tube-horn unicorn metamorphosis).

    • Ari Brockman

      Did you buy the EH tubes from Woo or on eBay?

      • Adrian Weinberg

        Actually i got a matched and cryogenically treated pair from ebay. Its not that they were cheaper (they were), its just that im in Australia and would have to wait for the Australian supplier to get the tubes. So far they only managed to get 6 units in the country, so getting a unit alone (I ordered very very early) i was lucky enough.

  • Adrian Weinberg

    double post.

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