DNA Stratus, V4 vs Woo WA5-LE, Gen 2 vs LTA MZ3

DNA Stratus, V4 vs Woo WA5-LE, Gen 2 vs LTA MZ3


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Intro

While trying to hone my audio knowledge in the process of finding sonic nirvana, I occasionally purchase used amps to compare to those which I already have. I listen to them, enjoy them, and decide which fits my own preferences best. My favorite stays, and the rest move to a new home. I am very fortunate to have three amps at the moment, and hope readers can learn something from my experiences. All three are fantastic amps, and nobody could be faulted for preferring any of them.

I have also chosen a tube complement for each amp that, to the best of my ability, tweaks the amp to my sonic preferences. In my personal experience, I’ve almost never loved a tube amp with “stock” tubes. Some amps need more tweaking than others, but it is worth noting that all amps improve at least a little with the right new tubes, and some improve a lot. With the exception of the MZ3, I personally wouldn’t consider buying/keeping the other two amps if I were forced to only use the stock tubes. Some folks will care less about tube upgrades, and some will care more, but I felt it important to point out for any readers newer to the hobby.

Finally, I think it’s relevant to mention my sonic preferences. I’ll try to be objective in terms of describing the sound of these amps, but it’s worth communicating what my goals have been in terms of gear selection, from chain to headphones to tubes. I love detail, speed, holographic imaging, a deep soundstage, and excellent voice separation. These being tube amps, I want to be transparent that I have never looked for “warming up” the sound, or rolling off any part of the frequency range.

Source Chain:

  • PS Audio Stellar Power Plant P3
  • Custom fanless NUC mini PC running Roon ROCK
  • Chord M Scaler
  • Chord DAVE
  • Upgraded power cables and interconnects

Headphones:

  • Focal Utopia

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The Contenders

DNA Stratus, V4
MSRP, Stock: $4,300*
With Upgraded Tubes: $5,330

  • Philips Miniwatt GZ34 Metal Base Rectifier: $500**
  • 2x Sylvania Spring Top 2A3 Power: $530 (pair)
  • 6N1P Input Tube (stock): $0 (stock - will try others in the future)

.* This pricing is not provided on the public DNA website and is subject to change. Please email Donald for the most up-to-date pricing
.* *This DNA Stratus is not optimized for use with a GZ34 tube. As per Donald, it is safe, but there is a slight sacrifice in noise floor. I use this rectifier instead of a 5U4G for it’s exceptional control.

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Woo WA5-LE, Gen 2
MSRP, Stock: $3,700
With Upgraded Tubes: $6,430

  • 2x Sylvania 6SN7W: $130 (pair)
  • 2x Philips Miniwatt GZ34 Metal Base Rectifier: $1,000 (pair)
  • 2x Takatsuki 300B: $1,600 (pair)

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Linear Tube Audio (LTA) MZ3
MSRP, Stock: $3,700
With Upgraded Tubes: $4,040

  • 2x Sylvania 6SN7W: $130 (pair)
  • 2x La Radiotechnique 12AU7: $210 (pair)

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Build & Form Factor

All three amps are incredibly well built, and I have no meaningful complaints about any of them. The footprints aren’t worlds off (if separate boxes are placed together), but you do scale down a bit as you go from the WA5 to the Stratus to the MZ3. The WA5, when put together and almost touching, is roughly 19”W x 16”D. The Stratus is only one box, but it’s relatively wide and deep at 17”W x 13”D. The LTA MZ3 comes off as much smaller, but if you put the linear power supply next to it, you end up with effectively a 16”W x 12”D footprint, though you could conceivably move the power supply to another shelf (if available), and the main unit itself only takes up 10”W x 9”D of space.

The WA5 is the most tankish, and weighs in at a rack-bending 70 lbs. I doubt many will want to place it on their computer desktop, but for those with a dedicated audio rack, there’s something I find utterly awesome about the way the WA5 looks and feels. It would look just as at-home on the console of a steampunk battle tank as it does on an audio rack, and I love it. This is also the only amp of the three to accept balanced inputs, if that is important in your system; I am all single-ended, so it isn’t a factor for me. My one tiny complaint might be that the input and power-level selector knobs to the left and right of the volume knob are a bit mechanically vague, as they don’t lock in place with as satisfying a click as I’d like. However, the volume knob and power knob are weighty and feel fantastic. Turning this amp on also feels like I’m starting up that steampunk battle tank.

The Stratus’ box is thick, sturdy, and very very blue. If you don’t like the color, tough; it’s the color you get if you wish to own the work of the amp master, Donald. On the one hand, I would have probably chosen a different color if I could have, but on the other, I rather respect that stance. Frankly, I rather like the idea that ownership of Donald’s statement blue amp enters you into a sort-of blue brotherhood. The chassis won’t flex in the slightest as you handle it, the switches all have satisfying and solid mechanical clicks, and the volume knob is precise, with a well-weighted and smooth resistance.

The MZ3 is the most unique, and I really really like what they’ve done with it. The design language fits well with its sound signature. It doesn’t put the tubes in your face, but rather has them just poking out of that beautiful, black cube, reminding you ever so discreetly that they’re there. Turning it on brings the highly pixelated LED display to life (LOVE this look), scrolling a notice that it’s “warming up”. The volume attenuation on this amp is truly unique. I can see some folks not loving it, but I do. It’s a stepped attenuation mechanism that always starts at zero remembers your last volume level for each input when you boot it up. There is no physical start and stop to the wheel, and there’s also a very satisfying (or annoying, depending on your preferences) click for every step. The chassis itself is the thinnest of the three amps, but a far cry from flimsy. It’s solid, yet light. Access to the tubes for rolling can be had by simply undoing 6 allen bolts in the top. The amp accepts a pair of 12AT7/12AU7 tubes (but NOT 12AX7) and a pair of 6SN7 or 12SN7 tubes, switching between those with a simple dip switch on the circuit board. It’s worth noting that the MZ3 can also be used as a preamp or even an amplifier for efficient speakers, but I didn’t test those functionalities; we’re about headphones, here. :slight_smile:

All in all, there’s a lot to love about each amp in terms of form factor, and this is truly just a matter of personal preference and space. If I had to choose on form factor alone, I’d probably go with either the monster coolness of the WA5 or the slickness of the MZ3, but, as it turns out, sound matters. Let’s get to that…
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Blackness of Background

It’s no secret that the Utopias are very sensitive headphones (104dB SPL / 1mW @ 1kHz), and don’t have a particularly high impedance (80 Ohms). As a result, they can be finicky to pair with tube amps, which often play well/best with higher impedance headphones. The slightest background noise will come through, and even if not consciously audible, will cause fatigue over longer listening sessions. Of all five tube amps I’ve owned, these three have the blackest background. Still, I have tried to assess varying degrees of virtually nothing.

On the MZ3, I cannot perceive any noise no matter what I do. Turning the amp all the way up (with no music) gives me nothing. Most telling, however, is listening. There is simply nothing in the background, and I could listen to this amp for hours with no fatigue (though, other contributing factors to that will be discussed later). Now, I’ve experienced with other amps the cause of the ultra black background seeming to be a result of it losing super low level micro detail, and that may be in play here, but to be frank, I cannot be sure. This amp can probably be paired with virtually any headphone and not produce even the slightest hint of noise.

The Stratus is also dead silent, and I can turn the volume knob to the max (no music) and not hear anything, so long as it is fitted with the (intended) 5U4G type rectifier tube. If I switch out the 5U4G rectifier for a GZ34, which the amp can accept but is not optimized for in terms of noise, I can get a barely perceptible hum at max volume. However, that really shouldn’t count against it. I use a GZ34 because it’s more tight and controlled than the 5U4G tube I have, but my doing so shouldn’t cause me to ding the amp on noise if I’m specifically putting in a tube that is known to not mesh properly with the amp’s carefully considered noise-reducing circuitry. Those who wish to buy this amp can opt for a rectifier switch (at extra cost) that allows the amp to run optimally with a GZ34 (or 422A or GZ37) tube.

The WA5 is dead silent at anywhere near listening levels, but technically comes in behind the other two because I can get a bit of hum as I near max volume (no music). I used to be able to just barely hear the amp even at listening levels, but that is before I became familiar with how to properly use the nulling pots, and between better tubes and honing the pots, I’m at absolutely no noise anywhere below 90% on the volume knob, and my listening happens in the 5%-25% range.

In summary, all three are great on noise. The Stratus and MZ3 just edge out the WA5, but only just.
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Staging, Imaging, and Separation

Staging is where these amps start to meaningfully separate, but critically, not into “better” and “worse” - just different. I fell in love with tubes in the first place because they added depth and dimensionality to recordings that I have never heard in a solid state amp. However, in return for that staging, many tube amps sacrifice too much of the detail, speed, and black background I want to retain. These three have been excellent performers on staging with few, if any, of the sacrifices.

The MZ3 ends up as a middle ground between the other two amps in terms of soundstage shape and depth. The moderate width and depth are coupled with incredible instrument separation. However, I again suspect that the extremely clear separation may be partially due to some loss of microdetail that would otherwise fill in the “room” of the recording. I don’t hear echoes off of walls and spaces like I can with the other two amps (or out of the DAVE, by itself, which is my reference).

The WA5 stage is wider, but shallower, and set back just a bit from the listener. If you want to feel more like you’re sitting back a bit from the stage and hear the performance from in front of you, this is a great choice. Separation is very good, but again, not incredibly deep. Still, notes and sounds have exceptional dimensionality and tangibility.

The Stratus takes your head and pulls it right into the music. It has the deepest, and most surrounding stage, by far. Others have described it as a “you are there” listening experience, and they’re absolutely right. Just like the WA5, notes have this incredible texture and dimensionality, and I feel like I can hear the note and the space around it (holographic imaging).

Between the three, my preference is for the Stratus, hands down. I enjoy the others very much, and this is purely a case of personal preference, but I find the feeling of being thrown into the middle of the music so incredibly intoxicating. Other folks would be entirely reasonable in leaning toward the other staging profiles, and it’s definitely fun to switch between them.
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Detail, Timbre, Speed, Control, and Frequency Range

Here, it’s important to note that both the WA5 and Stratus are single ended triode (SET) amps, and both perform more similarly than differently in this category. Detail and clarity are exceptional. Both amps preserve microdetail well, and the increased perception of space and depth the tubes bring allow you separate out and “peer into” more of that detail. I perceive no veiling (loss of clarity) worth noting. The timbre of sounds is more lifelike on these amps than any other I have heard - solid state or otherwise. I can feel a violin bow pull its string, a piano’s hammer striking its strings, a pick on a guitar string, drum hits, and a singer’s breath. Transients (the initial impulses of sounds), in particular, are incredibly crisp and realistic. In terms of stopping speed and control (preventing overshoot or ringing when a note stops), I’ve found SET amps to often struggle, and this is where tube upgrades make a huge difference. Both the WA5 and Stratus are frankly pretty poor performers here with their stock tubes, and come off as quite bloaty. However, good rectifiers go a very long way in cleaning that up. With my upgraded tubes, both are much more controlled, with the WA5 edging out the Stratus (though, I have more tube rolling to do on the Stratus to say for sure). For frequency range on the SET amps, the WA5 sounds a tiny bit thicker with a pinch more authority in the bass, while the Stratus is a smidge more even up and down the frequency range with a bit more air. However, I want to stress that the Status is far from thin or bass light, and the WA5 has plenty of air, too; the presentations just slightly lean in those directions.

The MZ3 is where things get really interesting. It has a truly unique topology, utilizing a push-pull circuit combined with their unique ZOTL (Zero hysteresis Output Transformer-Less) architecture. I won’t pretend to understand the ins and outs of the engineering, but I know it’s very different from other amps, and it sure sounds different. To start, you’ll immediately notice how crystal clear the MZ3 is, and it treats the whole frequency range utterly even-handedly, with gobs of space and air. It’s also incredibly well controlled, and can be considered as close to solid-state in that regard as I’ve heard. However, things get really interesting when we get to detail and transients. The best way I can describe it is via an analogy to photo editing. Imagine an image with incredibly crisp and sharp lines. Now imagine you took out the feathering tool and just barely touched up those sharp lines. That’s what the MZ3 sounds like. It is not blurry, it’s not smooth, and it’s certainly not veiled - but it’s not ultra sharp or crisp either. The “edges” of sounds which would otherwise be weighty or almost tangible are just … feathered a bit. This phenomenon is incredibly subtle, and it took lots of A/B listening before I could put my finger on it; one would be unlikely to even notice without an A/B scenario. When I finally was able to describe it to myself, my initial reaction was that this is a flaw. With more listening, I have realized that it’s actually a double-edged sword, and is desirable in some circumstances. To be sure, this amp will never be as convincing or lifelike as its SET brethren. However, oh my lord, this amp is easy to listen to - for hours. That slight “feathering” of the sound just eliminates any unpleasantness from every. single. recording. If you’re not hyper-focused and listening actively, the ultra black background, clear separation, and crystal clarity, combined with that almost intentional-seeming feathering, is so utterly relaxing. Not meaning this as a backhanded compliment at all, the MZ3 might be the best background listening amp ever made.
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Conclusion

Each of these amps ended up being quite distinctive, with more differences than strengths or weaknesses. Had I a magic audio wand, I would take at least some attributes from each amp and mash them together. Alas, this is not possible. At the end of the day, the amp that most often finds itself atop my rack is the DNA Stratus, and it’s the amp I would personally choose between the three. Again, I wouldn’t at all fault someone else for choosing either the WA5 or MZ3. As a matter of fact, even though I’d personally rank the amps as Stratus (1), WA5 (2), and MZ3 (3), if I could keep two, I’d make the MZ3 one of them. Either the Stratus or WA5 would satisfy me for that SET sound I’d want for more active evening listening sessions, and I would switch to the MZ3 all day while I work.

Rounding out the Stratus story, the unit I have on hand is a demo amp which I do not own, and it will have to move along soon. However, I liked it enough to place an order for its bigger brother, the Stellaris. I love that SET detail and realism combined with the deep, middle-of-the-music soundstage that I can hear wrapping around me. Given that the Stratus just edges out the WA5 for me, I knew that the Stellaris would be like the Stratus, but a bit more - and I cannot wait!

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Awesome write-up and review! I’ve never heard a DNA or the Woo WA5 but I’d like to eventually. Congrats on having this experience of reviewing all three of these at the same time. Having not heard the others in this review, how would you say the MZ3 compares in macro dynamics/bass slam/impact? Always a curiosity of mine. Thanks for your time and again, awesome review!

Oh, something I just remembered while reading your review. My MZ3 remembers the volume for each input. Interesting yours would reset to 0 each time. No a big deal, just thought it was interesting.

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Interested to hear @andris answer too. To chime in about the little brother Mz2 the main thing it lacked for me was that bass slam and heavy weight to instruments. Everything said above about the description of the mz3 is very similar to my mz2 reaction. If there was a way to add the mogwai’s tonal weight and dynamic slam with the liquid clarity of the mz2/3 it would be an interesting combo.

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Excellent and thorough comparison @andris. Very well done.

I’m looking to pick up an MZ3 (mainly for the preamp function), and with this and @Rhodey’s impressions/experience, it makes me more confident that it’s the right amp for me.

Cheers!

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Great write up very well done. Your comparison is very clear and concise. Donald does make fantastic sounding amps! Having own the starlett, I would’ve love to hear the new stratus with AN transformer someday. Your description on the Stratus’s staging is precisely the reason why I absolutely love my DNA and Eddie Current amps. It just sucks you into the mix. If you have the chance do give EC amps a listen. I have a feeling you will thoroughly enjoy it especially so if you enjoy SET sound. A different take on SET sound from Woo and DNA and equally as impressive. Hope you can get your stellaris soon!

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@Rhodey - I’m in agreement with @Earmuffs on this one. The tonal weight and punch is just softened a bit on the MZ3. Incidentally, I actually had the opportunity to borrow an MZ2 for a while, and I found it to be more blunted or smoothed than “feathered”, but neither the MZ2 or MZ3 will be winning an impact/slam competition among amps. It’s not like you’d ever listen to the amp and call it weak, but it won’t be as visceral or impactful as many others. I don’t have super extensive experience with electrostat headphones, but from what I have heard at shows, I’d almost say that the MZ3 brought my Utopias a bit closer to an electrostat sound. Super clean, more effortless sounding, but certainly a bit less punch.

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Ok makes sense. Good info and thanks for the reply!

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You know what, you’re probably right. I always turn my amps to 0 before turning them off out of habit, so that’s probably why. Good catch. :slight_smile:

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Just wanted to say that I really enjoy your tour through tube land. I even sat down at the computer to read through this instead of scrolling on the phone. =)

Thanks for your effort and for sharing with us.

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I am aiming to get a MZ3, but have also looked at the WA5 for a long time, they are both endgame gear for me and my European (+25% tax) wallet.

So thanks a lot for this comparrison it is both well written (you should do more, you have a talent) and filled with useful information and insights, that are easy to understand and relate to. And the 3 images re staging are just brilliant.

Thanks for a great review!

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An excellent review @andris. Very thorough and comprehensive with great detail. Thanks for a very enjoyable read.

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He has been killing it lately with these big ticket item comparisons. Awesome reviews that are super enjoyable and helpful especially when you have heard one of the amps as his reviews give you great comparisons that are easy and enjoyable to follow! Hope he throws a Nautilus in the mix soon :wink::crazy_face:

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I like the analogies you provided, thanks

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This is audio gear poetry - excellent review and tour of these 3 amps and builders. It isn’t very often that we get this level of comparisons, especially for premium tube amps.

Is your dating history as ruthless?

We listen for similar things.

Like a warrior/chef sharpening his sword/knives.

I understand it’s closer to $4500.

GZ34/5AR4 are not directly heated, whereas 5U4G and 2A3 are both directly heated.

I have found that the input tube is less important with DNA builds.

This suggests lower total cost of ownership, combined with longer tube life in microZOTL designs.

I view the MZ3 as most desktop friendly with triple threat capabilities.

Otherwise known as French Racing Blue! A DNA amp is a bit more accessible than a Bugatti Veyron.

It’s the only one of these 3 amps to feature this. Stepped attenuators come with the $10k plus DNA amps.

This is telling, especially for the WA5 and its higher power output that may be more susceptible to noise with a high sensitivity headphone.

Noteworthy.

I suspect this may be improved (in part only, given its push-pull design as elaborated on below) with higher end tubes (more than $340 worth used here).

Given the relative price-points and power output of these units, perhaps the Z10 is the LTA amp that is more in the same weight class as the Stratus and WA5. The MZ3 uses 6SN7 based power tubes, while the Stratus uses 2A3 and the WA5 uses 300B. The Z10 is EL84 driven and quite a bit more powerful than the MZ3.

I perceive this also. Staging (not necessarily width), imaging, separation, atmosphere, ambiance, room information are among DNA amps’ most core competencies – and contribute to its elevated emotional enjoyment (along with its harmonic richness while maintaining its overall polish and refinement), for me.

The Stratus generally comes with a $30 Winged “C” (SED) 5U4G rectifier. During my demo, I found a $60 NOS Tung Sol 5U4G tube to improve things - and serves as what I’d consider as a “baseline” Stratus (not being compelled to change tubes).

These are professional impressions/distinctions!

The MZ3 is different here where it’s OTL (LTA’s microZOTL version at least), push-pull, and solid-state rectified, whereas the others are transformer coupled, single ended triode directly heated, and tube rectified. Single ended triode amps are said to be more harmonically rich and textured where even order harmonics are preserved and not cancelled out as with push-pull designs. Some prefer that additional texture and information that comes with single ended triodes, while others prefer the reduced coloration of push-pull. There are use cases for each.

If we are referring to the same thing, this is as good a distinction between one aspect of the sonic differences between single ended vs. push-pull as I’ve come across – with respect to harmonic richness, tonal density, and texture.

This makes sense to me.

We cannot wait either! It is possible that you may prefer DNA with the XLR outs, especially given your sonic preferences.

Someone get this man an Eddie Current, Decware, and ampsandsound amp to compare/evaluate.

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@Deepy , @Gordon_Freeman , @Earmuffs , @prfallon69 , @cpp , @BoardmanGetsPaid , @ValentineLuke , @Rhodey , @perogie , @bpcarb - Thank you all so very much for your kind words. I’m genuinely honored that people actually found it worthwhile to check out what is ultimately a very long post. Ya’ll are awesome. This forum is the best! :beers:

@bpcarb - I feel like your reply has so much really helpful context and should be required reading as an addendum. Thank you! :slight_smile:

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lol - I did quite a bit of dating in my day, but I have fortunately found and married my human “Stellaris” :slight_smile:

Not for nothing, her WAF tolerance is so high that all I get is an eyeroll and an “I’m happy you’re happy” when I buy a Stellaris :wink:

Interesting. Yeah, I wanted to be really careful here, because I know his prices can change. I got quoted $4300 in May, so that price is a couple of months old, and supply chains are crazy nowadays. If anyone is curious, they should definitely email Donald anyway, as he’s an absolute pleasure to talk to and do business with. Class act.

I heard the same, and Donald seems to really favor the 6N1P. I did order a few 6BQ7A tubes (Donald-approved) to try out, and I’ll report back on the Stellaris thread.

I may or may not have ordered said stepped attenuator on my Stellaris… :grin: That said, to be clear, I actually didn’t go full-blown Stellaris Special. I got the rectifier switch and stepped attenuator as add-ons to the “stock” Stellaris.

I continue to be curious about this. However, it’s worth noting that I have used the exact tubes I put in the MZ3 in other amps (6SN7 in the WA5 and 12AU7 in the ZMF Pendant), and they didn’t exhibit those characteristics in other amps. Now, I absolutely allow that how a tube behaves in one amp could absolutely be different in another, particularly given a different topology, so who knows. I did feel that the La Radiotechnique 12AU7’s and Sylvania 6SN7’s were better than the stock tubes, but the overall sound characteristics were fairly consistent.

Yeah, that stock rectifier is not good. I also got a better 5U4G tube (NOS RCA), which was meaningfully better than the Winged C, but still nowhere near as controlled as the GZ34 metal base. The 5U4G tubes were definitely quieter, but I just so badly wanted the amp to be just a bit tighter. I’ll be doing a lot of rectifier rolling when the Stellaris comes. I’ll be getting at least a few 5U4G variants (new production and NOS) as well as a WE 422A (provided I can find one) to try out.

100%, and I truly understand the desire for either (or both)! The MZ3 is so friggin clean. It’s beautiful.

I’ve been holding off, but I think I may have to finally just order a balanced cable (from Trevor at Norne Audio, of course)

YES, PLEASE! :smiley:

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This has turned into such a good thread/discussion. Awesome info @bpcarb and @andris.

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From Starlett, XLR out balanced drive to Utopia provides just a smidgen more control - smidge, minor, mild, over SE out via XLR. Can only tell when doing quick A/B, which you can easily do. Whether its more apparent on the Strat/Stell is unknown to me but I have heard people say the same thing.

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I’m sure enjoying my Eddie Current Studio B that I got last week - giving it input from an M Scaler and a DAVE into Utopias or VO’s gives you some pretty decent sound!