Presently, I think I am the only Head-fier that has both the Woo WA5 and Eddie Current 4-45 in the house. I have had these amps here for about a month or two.
I am writing this post because I want to write down my impressions before I sell the amp. If I re-purchase a Woo product some other day, it will either be a Woo WA234 or the upgraded version of the WA5. I am selling the WA5 mainly because of space concerns, but I will miss it dearly.
As I have posted my impressions earlier, I do not think it is as simple as saying that the WA5 is bettered by the 4-45. One has Purrin's post on the best amps for HD800 in mind. In that post, he opined that the WA5 is unable to compete with the "big boy" tube amps such as the 4-45. I do not necessarily agree with that observation as I shall show that the choice between the two boils down to one's subjective preferences (and I do not think Purrin disagrees).
These are my impressions using the HD800 and, to a much lesser extent, the SR009 through Woo WEE. The HD800 uses a balanced 4 pin XLR Cardas Clear cable and is modded with rug liner material and foam covering the trapezoid only.
My DAC is the AMR DP-777 fed by an Audiophilleo PP1.
When one is comparing tube amps, it is most important to note what tubes one is using. The WA5 is often provided with stock tubes in meet conditions and those, frankly, make the WA5 sound like a $500 amp.
Allow me to take stock of the tubes I am using for both amps:
- For the WA5: AVVT AV32B, GEC U52 and Sylvania 6SN7W metal base or Tungsol 6SN7 BGRP.
- For the 4-45: Globe UX245, OTK 6C45Pi and stock rectifiers.
I use other tubes as well but I found these to be the best combination for the comparison. For extra tube warmth, the WA5 may be coupled with the Tungsol 6SN7GT BGRP. The 4-45, on the other hand, may benefit from a more modern Hifi sound with the EML 45 Solid Plates - which I did not use in this review as they have yet to be burned in.
The WA5 reacts more significantly to tube changes than the 4-45. I find that the soundstage of the WA5 widens considerably with the change of rectifiers and slightly more with higher end output 300B tubes. The rectifiers clear up the mud in the sound as well. The 300B output tubes improve the high and low end extension significantly. Tonality and resolution are in turn influenced by the driver 6SN7 tubes.
The 4-45 is not as much influenced by tube-rolling. An argument may be made that because of this, the WA5 is more tube reliant in its design and therefore is bound to be prone to tube distortion. I would suppose that my subjective impressions (below) are consistent with this. Please take this with a grain of salt: I am not an amp designer. I would not know if the 4-45 is “technically superior” than the WA5.
After listening to both amps and A-Bing them for about a month, my conclusions are that both amps are top tier amps that excel at imaging, soundstage and details. The differences, which are noticeable but not game-changing, are as follows (in decreasing order of audible significance):
What the 4-45 does better than the WA5
- Speed, attack and decay
- Pin-point imaging
- Treble sparkle and air
- Laid back and better for long listening sessions
- Wider soundstage
- Resolution and micro detail
- Lower noise floor
- Bass resolution and more precise attack
What the WA5 does better than the 4-45
- Lush mid-range beauty
- Front row presentation and imaging
- More dynamic and engaging
- Euphonic and occasionally more fun and musical
- Bass extension and bloom
I will deal with my specific impressions on a selection of tracks in the post below.
A word about the HD800 mods
I used to think that the HD800 sounded terrible with run-of-the-mill recordings on the WA5, even with upgraded tubes. The HD800s in stock form just sounded too grainy and harsh on certain recordings for my taste. With the WA5, it was really the best recordings that brought the HD800 to the forefront in my mind as the best headphone in my collection (bar the SR009 which is not properly driven, yet). As I used to think, the HE-6 sounds great on 80% of the music while the HD800 sounds even better on 10% of my collection.
Then came the 4-45. The recessed treble and laid back presentation made the HD800 much more bearable. I pronounced on the 4-45 thread that the harshness of the HD800 was then gone! I could listen to everything and anything on the 4-45 (with the less clear and accurate WE 417A) without much fatigue, despite the inherent brightness of the amp and headphone. The reason for this, I surmise, is the fact the forward voicing of the WA5 which pushes the HD800's harshness in its upper midrange and lower treble in your face.
But soon the harshness of the treble reared its ugly head. I resorted to well-recorded music again, though the 4-45 was still smoother, laid back and more listenable than the WA5. I also found that I had to use the less accurate WE 417A driver tubes on the 4-45 because the 6C45Pi was too bright to be listenable.
The only solution, I found, was to mod the HD800.
And it works. The WA5 and HD800 combo is now a wholly plausible proposition. Most music well recorded or poorly recorded sounds amazing on the WA5. As for the 4-45, as I have endeavoured to explain, equally if not even more amazing. I could use the better 6C45Pi without having to grimace at the treble. But for those who want to stick to their stock HD800s, I would say get the 4-45 and avoid the WA5.
We have to thank Anax and Purrin for promoting this mod. It is really worth it.
The Hifiman HE-6
I have said very little about the HE-6. Well, I simply did not have the time. To me, the HE-6 driven by the WA5 is marvellous, possibly one of the best amp-headphone combos for the HE-6. I believe Justin_Time agrees with me on this.
But the 4-45 just takes the HD800 to another level of detail, speed, soundstage and imaging with which the HE-6 can never dream to compete. It is the sort of sound that brings the HD800 into SR009 territory. And having both headphones in the house, I think that statement is no hyperbole. Moreover, the HD800 is supremely comfortable on my head, while the HE-6 is heavy and grasps the sides of my skull with the claw of fury and vengeance.
The HE-6 is therefore, much like the unmodded HD800 when I only had the WA5, somewhat relegated to a corner in the room. I always dreamed of having a wonderful set of headphones that could play with any kind of music (like the HE-6) and that felt comfortable on my head. That seemed like a remote dream until I settled down with my modded HD800 and 4-45 set up. That said, the HE-6 is still a fun headphone to use for that amazing deep bass and ridiculously visceral impact once in a while.
So you may ask, how does the HE-6 sound on the WA5 and 4-45? Well, the HE-6 is much better driven out of the WA5 than the 4-45. The WA5 plays all the HE-6’s strong cards where the 4-45 emasculates it. The deep bass, palpable and tangy mid-range is weakened on the 4-45, though I must say the soundstage is wider. The HE-6 + WA5 is also the most euphonic combo that I’ve heard with my headphones. It renders voices very nicely. There is little contest in this regard.
At the end of the day, these will also have to factor into one’s consideration when one is thinking of buying the 4-45 or the WA5. If HE-6 is your main set of headphones, the 4-45 will not do them justice, or as much justice, as a WA5.
Without a doubt, the WA5 looks and feels better built than the 4-45. The WA5 is carved out of machined aluminium and looks oh so beautiful.
The 4-45 looks more functional and has a smaller footprint. I do not think it is hideous but it is not beautiful either. I note that my version of the 4-45 does not have protruding transformers but internally it is exactly the same as the production version. Some think this looks better than the later production versions.
The speaker output posts of the 4-45 look a lot cheaper compared to the WA5. It does not seem to affect sound, however.
Both amps are two-box solutions, with external power supply units to prevent noise. The tube rectifiers on the WA5 protrude externally while the tube rectifiers are held within the chassis of the PSU unit of the 4-45.
The volume attenuator on both are smooth and not stepped. The one on the 4-45 is made of plastic and definitely feels less high quality than the aluminium attenuator on the WA5, which is so far the smoothest volume knob I have ever used.
The outputs for both amps seem solid. The 4 pin XLR outputs are of the same construction.
The WA5 has a switch between different headphone impedances and gain. The 4 pin XLR plug is specifically designed for the HE-6 and K1000 and therefore outputs more gain and power into (I think) 50 Ohms. It is important to note that there is significant hiss driving the HD800 through the XLR output of the WA5 and it is not recommended by Jack Wu.
The 4-45 seems to be designed in a way that the same outputs can be used with any headphone. I have not tried IEMs but the 4 pin XLR worked fine with the HD800 and the HE-6. The output impedance, correct me if I am wrong, is very low, which enables this. According to Craig, the internal wiring for the XLR outputs is the same as the speaker outputs, so nothing is to be gained by driving the HE-6 through the speaker outputs.
Both amps take single ended RCA inputs only.
Can I pronounce a clear winner? No, I can’t. The WA5 and 4-45 will have their own fans. Those who prefer a detailed, smooth, front row, euphonic and bass heavy presentation to their music will love the WA5, as I did. Those who use the HE-6 as their main pair of headphones will also love the WA5.
But for those who are in the pursuit of realism and transparency, and prefer a less forward and engaging sort of sound, the 4-45 is the clear choice.
Unfortunately for me, tomorrow is the day that I need to say goodbye to my WA5.
Edited by lojay - 10/31/14 at 9:33am