Woo Audio1 Review
Mar 30, 2004 at 3:05 AM Thread Starter Post #1 of 23

CWCalk

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My attempt (long) at a review of the Woo Audio1 discussed in thread: 65836 is set forth below. As posted in that thread, I am happy to lend the amplifier to a "known" head-fier to take to a meet.

Woo Audio1 Headphone Amplifier

Disclaimer

I have no association with Woo Audio or Mr. Woo and first learned about the Woo Audio1 headphone amplifier (“Woo Audio1”) through the head-fi thread, thread ID 65836.

Executive Summary

The Woo Audio1 holds it own against my two other headphone amplifiers that have a significantly higher list price. The Woo Audio1 creates an open, full, airy soundstage with detail and accurate reproduction that seems to capture the best quality of tube amplifiers. Bass reproduction is equal to or better than my two comparison amplifiers without a noticeable degradation in detail. Perhaps best of all, there is a noticeable absence of tube hum making quiet passages dead quiet.

Background

Although I have been a latent/active audiophile for years and have read many reviews this is my first attempt at any written review of an audio product. For reference, my current system set-up is listed in my profile. My “Headphone Systems” are listed in my signature.

I also have a collection of other components that see time in various other system configurations. These other components include other solid state and tube amplifiers, pre-amplifiers and sources. While I doubt I have very discerning ears/listening patterns, I have had the opportunity to listen to many different components. My musical tastes run from Classical to Rock to Jazz.

For this review, I used a Marantz SA-14 SACD/CD Player as a source. The SACD player output was carried by Tara Labs RSC Air3 interconnects to a VAC Standard Pre-Amp. Goertz MI interconnects from the Tape Out on the pre-amp. were connected to the inputs on the headphone amplifiers. While this approach may be less than ideal it allows me to use the SACD in both a headphone system and a conventional speaker system without having to disconnect and re-connect interconnects. The Tape Out of the VAC Pre-amp. is a pass through circuit and the pre-amp. is turned off when using the headphone amplifiers.

I compared the Woo Audio1 to my PhillyAudio8 and Melos SHA-1 (un-modified). The same Signal Cable Power Cord was used for the Woo Audio1 and PhillyAudio8. The Melos SHA-1 is an early model with a permanent power cord.

For listening comparisons I tried listening to a song, or passage of interest, and then replaying the same passage on the other two amplifiers. I also compared the sound of all three amplifiers with Sennheiser HD600, Allesandro MS Pro (bowl pads) and Grado 325 (flat pads) headphones.

I used the following SACD/tracks for reference when comparing the amplifiers.

Johnny Cash, Live at Folsom Prison SACD (male vocals)
Alison Krauss + Union Station Live SACD (female vocals, instrumentals)
Dave Brubeck, Time Out SACD (piano, bass, alto saxaphone drums)
Anna Sophie Mutter, Beethoven Violin Concerto SACD (violin, orchestra).


Initial Impressions

The Woo Audio1 arrived in a non-descript cardboard box sealed with duct tape. The duct tape was an initial turn-off, but after opening the box I found the Woo Audio1 to be extremely well packed in Styrofoam. In fact I suspect the box could have been dropped from 10 feet without damaging the Woo Audio1 (another application for duct tape). It took me over 10 minutes to extract the Woo Audio1 from the box and packaging materials.

The pictures on the Woo Audio website http://mysite.verizon.net/vze89mqs/ provide an accurate depiction of the Woo Audio1. The construction is very solid, with the close tolerances on the seams among the parts. The Woo Audio1 is probably not going to win any beauty contests, except perhaps among DIY enthusiasts. The front panel includes a volume knob, RCA inputs, a headphone jack, and a blue LED power light. (This light is pretty cool and is hard to identify in the website pictures unless one is looking for it). The volume knob is not stepped, the RCA interconnects are gold and very tight, and the headphone jack looks fairly generic. The large center tube (an RCA 7843 (NOS?)) is removable and the small front tube (a SOVTEK 6922) is held in place by a wire cage. The transformer, assembled by Mr. Woo, is an impressive 5 inches in diameter with a cover that looks like an upside down coffee can.

The back of the Woo Audio1 includes a fuse cover, power cord receptacle and a small silver toggle switch to power up the amplifier. The Woo Audio1 ships without a power cord. My views on this subject are set forth in the following post http://www4.head-fi.org/forums/showt...hreadid=60527.

Listening Impressions

HD600

After installing the RCA 7843 tube, I plugged in the power cord and interconnects, plugged in my Sennheiser HD600 headphones, turned the Woo Audio1 on and listened without the SACD playing. I heard nothing, no tube hum, no tube hiss, nothing. A good start.

In contrast, the PhillyAudio8 has noticeable tube hum, from both the 30? and 250? outputs. The Melos SHA1 is also quiet, and perhaps has a blacker quality to the quiet.

My first SACD was Dave Brubeck’s Time Out. The Woo Audio1 surprised me with a fullness/openness to the sound that was lacking in the PhillyAudio8. The bass in particular was noticeably enhanced. It was so noticeable in fact that I worried about mushiness to the overall sound. My fears, however, were not realized as the cymbals and brushes came through in clear detail. In “Take Five” the Woo Audio1 faithfully transmitted the slam of the bass drum pedal, the crisp sound of the sticks against the snare and hollow sound of the tom tom. The Melos SHA1 held its own and perhaps was slightly more detailed with slightly less bass, and slightly less slam of the pedal against the bass drum.

Next came the Alison Krauss + Union Station Live SACD. Alison’s voice sounds great on all three amplifiers. On the Woo Audio1 and Melos SHA1, the solo passages on the Dobro (a mechanically amplified guitar (I looked it up)) are sufficiently detailed that it was easy to imagine being in the audience. My preference for the “tube sound” makes my current preference the Woo Audio1 slightly preferable over the Melos SHA1. The Woo Audio1 imparts slightly more airyness/fullness to the sound without more than a barely perceptible loss of detail. The sound from the PhillyAudio8 also held up well to these tracks.

Next came Johnny Cash, Live at Folsom Prison on SACD. Johnny’s voice comes through was clarity on all three amplifiers. I particularly listed for the sound of the hammer hitting the railroad spike during “The Legend of John Henry’s Hammer”. Both the Woo Audio1 and Melos SHA1 made it easy to identify the metal against metal sound. As an aside, on the first track of this album a telephone rings in the distance during the first track (it is a live recording). The first time listening to this track on the Woo Audio1 I took off my headphones as I thought a phone in my house was ringing.

Finally, I listened to the Mutter/Beethoven Violin Concerto SACD. It is difficult for headphones, or many speakers for that matter, to accurate portray the complete soundstage of an orchestra. The Woo Audio1 does an admirable job however conveying an orchestral presence to the soundstage and separating the various instruments. The violin solos are also conveyed with accuracy, including the bowing and various high notes reached in the violin passages. The tympani and bass are also provided with a presence.

The Melos SHA1 also performs admirably. Detail is perhaps greater, but the soundstage is perhaps slightly less full.

Allesandro MS Pro / Grado 325

I replayed each SACD using the Woo Audio1 listening through the Allesandro MS Pro and Grado 325 headphones. The sound quality was more similar than different. Most remarkable was that despite their lower impedence, the Allesandro MS Pro’s were also dead quiet through the Woo Audio1 in the absence of input from the source. The cymbals in Take Five were still crisp but somehow not as appealing with the MS Pro’s. In contrast, the Grado 325’s seemed to return a quality to the music that made them more appealing.

According to his website, Mr. Woo “tunes” each Woo Audio amplifier using Sennheiser HD 590 Headphones. As a result, if ones audio tastes are similar to Mr. Woo’s the HD 600 are probably a better match with the Woo Audio1. I found both the HD 600’s and Grado 325’s enjoyable. These two headphones, however, tend to be my headphones of choice for all types of listening except when portability is required.

Conclusions

I like the Woo Audio1. Is it the be all and end all in headphone amplifiers? Probably not. For its $400 list price, however, the Woo Audio1 delivers an airy and expansive sound that should appeal to tube lovers. I like its sound and intend to keep it in my system for some time.
 
Mar 30, 2004 at 3:19 AM Post #2 of 23
Sounds like a winner!

Excellent review, especially if it's your first.

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Mar 30, 2004 at 3:22 AM Post #3 of 23
Congrats on the payoff for taking the chance and buying this product, and then sharing your thoughts with us about how it sounds. I guess Dr. Woo is going to have a hit on his hands as it sounds like it is quite good for the money.
 
Mar 30, 2004 at 3:43 AM Post #4 of 23
Congrats on making a nice purchase! I had a sneaking suspicion it would be nice
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Mar 30, 2004 at 4:14 AM Post #5 of 23
Well done, CWCalk - both the excellent review, and the boldness to give this amp a try.

Thanks for sharing your experience in a logical, easy to follow, and meaningful way. Always good to have reviews feature comparisons with other basline amps and/or cans.

Congrats on a nice amp.
 
Mar 30, 2004 at 6:51 AM Post #8 of 23
Glad to read that it sounds good. I think the amp actually looks pretty nice, but then again I thought the original industrial-look Singlepower amps looked nice too. It'd be neat to see how that amp would stack up to a PPX3, which is near it in price and also known as a great value for the money in tube amps. Very good review, and it looks like Mr. Woo might be getting a bit busier than he may have expected given how Head-Fiers jump on bargains
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Mar 30, 2004 at 11:40 PM Post #10 of 23
Nice review indeed! By the way, which headfier is getting a stax amp built by Mr. Woo?

From the site:

"I am currently making a Electronstaic headphone amplifier for a head-fier. I have some solid improvements to this design."
 
Mar 31, 2004 at 12:59 AM Post #13 of 23
Been waiting for your impressions, thanks a lot! Very interesting amp. Great job.
 
Mar 31, 2004 at 1:36 AM Post #14 of 23
seems like a nice amp, and for $400 it is quite affordable too.

I find the RCA inputs to be located on the front panel by the headphone output to be a bit strange... did this ever become a problem and do you know if it can be moved elsewhere?
 
Mar 31, 2004 at 1:45 AM Post #15 of 23
Can you post pictures of the unit in your system? I can host them if you need a host.

I just realized that using these with my zu cable oxyfuels would be rather...inconvenient. Wish the inputs were on the back. Or if he wanted to keep things close, maybe the sides.
 

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