Woo Audio WA7 vs. O2+ODAC: My Musings and Review
Jul 17, 2013 at 12:10 AM Thread Starter Post #1 of 3

Sonido

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First Impressions
 
So my WA7 arrived today. I had it shipped to work and was listening through my Sennheiser HD 700 while at work. I didn't have my O2+ODAC readily available, but first impressions I could already tell it was better. How much better? Well I started hearing sounds I could not before. For a moment there I felt like I had a different pair of headphones on. The sound signature was much warmer, which is to be expected since the WA7 is a tube amp. The bass was deeper and had an even fuller body. But the most impressive of it all was the more revealing nature of the WA7 compared to the O2+ODAC.
 
ODAC vs. WA7 DAC
 
ODAC -> O2 -> HD700
vs.
WA7 DAC -> O2 -> HD700
 
Once I got home, I first wanted to test the DAC of the WA7 vs. the ODAC. What I found was similar to my initial impressions. So much so that I wondered if it was really the DAC that made the difference. I was able to test more efficiently by hooking both usb dacs up and connecting the WA7 to the O2. I switched back and forth the default sound device in the Windows playback devices, so it was an instant switch between the dacs while I played the songs. The WA7 DAC seems to create a wider soundstage, and reveals more. I did some extensive testing and it seems that the WA7 is able to pick up fainter, lower volume sounds and still transmit it to my headphones. I guess you could say the WA7 DAC has a lower floor in the volume of sounds that it can pick up. I think this in turn creates that sense of being more revealing since more sounds are being reproduced at once across a wider volume range. Paired with the wider soundstage, it really is pretty impressive.
 
Besides being more revealing, the WA7 DAC also has a general sense of being more refined and smooth. Like how the ODAC really made the HD700 sound less raw compared to straight from my smartphone, the WA7 takes it further, making the ODAC sound raw and jagged. I would say the WA7 is also more forward than the ODAC.
 
 
O2 vs. WA7 Amp
 
WA7 DAC -> O2 -> HD700
vs.
WA7 DAC -> WA7 Amp -> HD700
 
This one is a bit unfair. It's kind of like comparing apples and oranges since one is tube and the other solid state. The fuller bass from my initial impressions is definitely due to the WA7 amp. After listening to the O2, upon switching to the WA7 is the sound seeming more lively and faster. The sound is more realistic and more like as if you're listening live compared to the O2. This could be attributed to the warmth.
 
The biggest thing I realized is how the WA7 really makes good use of all the sounds compared to the O2. By this, I mean the WA7 does a much better job at cleanly representing each sound that is heard. The WA7 DAC reveals more, and every sound that is put out is taken by the WA7 amp and produced with individuality. When the O2 takes all the sounds the WA7 DAC puts out, it does a far worse job with it. The best way to describe it is that the sounds seem to compete more with one another. Ever try to hone in on a single instrument playing subtly in the background? Much easier to do on the WA7. One song I tested with had a bass guitar solo. In the middle of it, a more powerful bass guitar line joined in and overwhelmed the original, as the first one died down slowly. You can clearly hear both bass lines simultaneously with the WA7, but not so much on the O2.
 
 
A Final Test
 
WA7 DAC -> WA7 Amp -> HD700
vs.
ODAC -> O2 -> HD700
vs.
HTC One (My smartphone) -> HD700
vs.
My laptop -> HD700
 
I wanted to give an assessment on how much an improvement the WA7 is over the O2+ODAC, as compared O2+ODAC vs. my phone and the stock sound of laptop. This should give a sense of the value since the WA7 is $1000, more than 3x the price of the O2+ODAC at $300. I will be using a number scale to represent each. There is no range to the scale. Instead, the scale should be used more as showing the difference between each.
 
Laptop: 10
Quick impression:
- Everything is flat. Lack of body in all frequency ranges. Probably due to lack of amp.
- Not revealing at all. Due to stock DAC.
 
HTC One: 80
This phone is actually a solid music player. It has the latest Snapdragon DAC by Qualcomm and a built-in amp. I do choose to have Beats turned off.
Quick impression:
- Reveals about as much as the ODAC.
- Does show rawness especially at higher volumes. Not as smooth as O2+ODAC. Probably due to built-in amp not powerful enough to drive 150 ohms headphones properly. The rawness is less apparrent on lower impedence headphones such as my HD598 (50 ohms).
 
O2+ODAC: 100
At least 10 times better than laptop.
 
WA7: 120
About 20% better than the O2+ODAC.
 
You may be wondering how after all the praise I've given to the WA7, how it's only 20% better than the O2+ODAC. The O2+ODAC is a very solid device that completely blows away the laptop. High fidelity is all about marginal returns and trying to get that last 1%. To me, this 20% increase in overall sound is very much worth the price. The key takeaway to this is to please do yourself a favor and get a dedicated DAC and amp if you're still using your computer's stock soundcard, especially if you have or are looking to get a pair of better headphones. Modern day music devices like smartphones or MP3 players even blow my laptop away in sound quality.
 
Note: My O2+ODAC is combo unit from JDS Labs and does not allow me to play DAC-only mode, so I could not pair it with the WA7 amp for testing. I regret not getting it separate or getting one that has RCA out such as from Mayflower.
 
Jul 18, 2013 at 4:43 PM Post #2 of 3
I distinctly recall someone asking about whether they should get either combo in one of the WA7 threads, so thanks for the great write-up of your comparison.
 

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