Shortest Way 51 (SW51+) Amp Impressions (Only)

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by Koth Ganesh, Sep 28, 2019.

  1. ckhirnigs

    ckhirnigs Friend

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    I can now vouch for these RFT EF184 tubes in the SW51+. They sound great rolled in the amp with my Bifrost 2 and ZMF Auteur. It’s hard to say how they differ from the stock tubes, but I do feel like the soundstage feels a little larger. The highs are smoothed to the point of making me want to turn the volume up a little more that normal. Overall, I really like the tubes and think they’re a great alternative to the stock tubes. They were only $6 each on eBay coming out of Russia. They even arrived quicker than the tracking info estimate.

    On top of the incredible value proposition this amp offers up, most of the tubes available are incredibly cheap! I think the seller I bought these RFT’s from on eBay has 4 of them left in stock.
     
  2. Emojiless

    Emojiless Acquaintance

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    Plenty has been said about V2 vs SW51+ for HD650 and I agree with most points. But my main headphones are HD800S and I figured more impressions with with HD800S could be useful.

    This is my first time writing impressions and I don't think I have a hearing as good as most people here or know how to express myself in audio terms properly, but I'll try

    Chain: PC (Tidal) -> Modius -> SW51+ / Valhalla 2 -> HD800S primarily (also HD6XX)

    I didn't much like stock tubes for HD800S on both Valhalla and SW51 (I did like them on my HD6XX tho)
    Valhalla on stock tubes a bit unfocused, and too light touch, always want to increase volume and sounds a bit lacking
    On SW51 stock tubes bass is one note and annoyingly punchy in a bad way like limpy bass emphasized. With HD800S its a pronounced snowglobe effect - snowglobe is slightly larger than my head, I find it interesting but fake. Not enough stage for games/movies, not even with VSS I find

    So majority of listening was done with other tubes that were recommended on SBAF - 6CG7 for Valhalla and RFT184 for SW51. I liked HD800S on these tubes. Impressions for them below.


    Still not entirely happy how SW51 does bass but it's a lot better comparing to stock tubes. Perhaps it's not SW51 but Modius at fault here as I hear fat bass with lack of detail. Interestingly that doesn't apply with Valhalla at all - the midbass control is very good and the boosted bass of Modius doesnt sound fat but thunderous. Its surprising - HD800S can do bass like this? (Makes me want to try Mjolnir 2)

    Valhalla is more ballsy with the bass and has better macrodynamics, more noticable slam. In general its a more edgy and alive sound. Valhalla sounds like it makes the driver work more while SW51 is more effortless. That effortlessness is very interesting - it's flowing as if past and present is more intertwined than usual. When I try to listen closely it's hard to grasp how did it just sound (am I on drugs?). So if SW51 sounds more flowing, the Valhalla sounds more pushed sound. It's a more edgy and alive sound. Valhalla can rock my socks off but delicate music still sounds touching. Valhalla tries to excite me while SW51 is just normal, maybe too normal. Excitement has a price - I tend to be more engaged, listen louder and get a bit fatigued. This doesn't happen with SW51 - I can listen for hours. The treble on SW51 is... normal. On Valhalla I can hear that it's dry but it doesn't bother me. S is more pronounced on Valhalla though. The mids are great on both but the RFT184 tubes do lose a bit of magic going from the stock ones.

    Biggest problem with Valhalla is the veil. I don't hear it at first but I start hearing it after a while. Somehow I find it more annoying in games - for some games I just don't feel as immersed because of the veil.

    The stage on Valhalla is pretty wide, on SW51 with the RFT184 it's a bit smaller but has more depth. Valhalla tends to be more wall of sound while SW51 is more holographic. Images on Valhalla are bigger. Stage on SW51 is less foggy and has better imaging. Valhalla sounds more open, like you are in a bigger space. SW51 has better imaging, especially noticable in games - know exactly where sound is coming from.

    Which is more immersive? Valhalla can sometimes be more immersive due to how weighty and aggressive sounds are, it can be scary. But other times its veiled and there seems to be some fog hindering the immersion.


    Music
    Hans Zimmer - Dune (Original motion picture soundtrack) (mostly first few songs, especially Leaving Caladan)
    Valhalla 2 6CG7 - scary, grand, big, impressive - reminds me of when I saw this in the theatre, goosebumps. The original feelings of profoundness and grandness that I felt reading the books and watching the movie, it's here.
    SW51 RFT184 - enough space to breathe but not as impressive, lacks powerfulness in comparison
    SW51 stock - too congested, least impressive, but emerges from blackness more


    Dire Straits - Money For Nothing
    Valhalla 6CG7 more alive and enjoyable, I want to rock more

    Lindy Ortega - Liberty
    More magic with SW51, especially stock tubes

    Alison Krauss - Live
    Sounds more open and I enjoy strings better on Valhalla, they are more emphasized
    Strings on SW51 are more ping, on Valhalla more twang

    Listening to more of some various music, I feel like with SW51 I am sometimes a little bored with it while Valhalla wants to grasp my attention - which is exactly what I want HD800S to do, my HD6XX is for background listening for me.

    Rereading what I wrote, some of the more negative points are perhaps me shitting on the Modius, I suspect its the bottleneck in my system. I probably need to upgrade to Bifrost 2.

    Most importantly
    For HD6XX more goosebumps with SW51
    For HD800S more goosebumps with Valhalla

    Gaming
    Rise of the Tomb Raider and Amnesia Rebirth
    Valhalla was veiled and felt like sound is a bit disjointed from whats happening on screen, not so with SW51 - felt more like I'm there

    PUBG
    This game has great sound design and sounded great on both Val and SW51 but I found I could hear better where my enemies are when they were above or below me with SW51


    SW51 RFT184 > Valhalla 2 6CG7 > Valhalla 2 stock >>> SW51 stock
    I feel more "there" with SW51 RFT184 although I lose some of the epicness of sound


    Conclusion
    I am happy with SW51+ with RFT184 tubes and I will stay with this amp. For me SW51+ is THE amp for my HD6XX but with HD800S I'm not so sure.

    I am very interested in Zampotech next project (if it's ever on the table considering what's happening in the world atm).
    What I would like on a more expensive SW51 version:
    To be a TOTL option for HD800S
    Thunderous deep bass, not punchy bass
    Slightly livelier sound
    The coveted nebulous DNA/EC soundstage that I can't afford
    A more satisfying weightier volume knob
    Balanced input/output
    All for price under 1k


    Side note, could someone please compare SW51+ against Mjolnir 2?
     
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  3. purr1n

    purr1n Desire for betterer is endless.

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    ^ Those impressions between Valhalla 2 and SWT51 are spot on. I couldn't have stated it better myself.

    Mjolnir 2 packs a big wallop and has a nice warm tone. The highs have a bit of edge like Valhalla. SWT51 doesn't have that punch but still wins in the effortless and fluidity department. Most SET amps will be like this. Mjolnir 2 is engaging as well. Perhaps not as pushed or force as with Valhalla and not effortless and SW51, but somewhere in the middle.

    To get the best of all worlds (no veil, lively, smooth, slammin') I suspect it would have to be the Folkvangr, but that amp does not exist yet.
     
  4. JackFruit

    JackFruit New

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    I believe upgrading the dac will give you what you want. After I've upgraded from Zen Dac to SMSL D1SE, I now have that exciting bass oomph and better bass control at the same time. Also way better timbre, speed, depth and way more details. The soundstage is a bit smaller, but more realistic at the same time. Separation is bad - my only grudge with this dac.
    I also recommend experimenting with usb cables if you're into usb audio, I use different usb cables for different music and for different amps.
    And I'm in the process of building of my first DIY power cable, will post my impressions later

    I've compared the bass of Asgard 3, SoundblasterX G6, Zen Dac, Burson Soloist 3XP, Xduoo MT-604 and SW51. And I can assure you that SW51 has the most fun and textured bass of them all. Slightly lost in control to S3XP, but that was expected
     
    Last edited: Feb 28, 2022
  5. Vtory

    Vtory Audiophile™

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    SW51 Loaner Impression

    As I probably stated elsewhere, this is NOT my first time to try out SW51 (may simply call it SW henceforth). When I had it in the house a couple of years ago, I was, well, underwhelmed, mainly because I set the bar too high. This amp was praised so enthusiastically atm and I was not good at translating hypes as I am now. This time around I did my best to give it a fair evaluation.

    Testing Chain
    • DX3 pro → SW51+ → Headphones
    • Associated headphones: HD6xx mod / HP1 stock / HP1 mod / Arya / Susvara
    • I used DX3 because I couldn’t place the amp well where my primary rig was located (physical conflicts). I ended up setting it in my secondary rig.
    • For the comparison, I used DX3’s built-in headphone out as a control/baseline to assess SW51’s basic capabilities. I also compared SW to my main amp, iFi Zen Can Signature to evaluate SW’s competitiveness over decent SS in the similar price range.
    • Most of the evaluation time so far was spent with HD6xx-SW pairing.

    Sound (vs control)
    • Bass is slightly lean by comparison, but far better controlled and articulated. Almost as good as SS. But probably due to the transformer limitation, I don’t think SW had the lowest notes strong enough. Fortunately, this issue is not very obvious with 6xx which is inherently weak at bass anyway.
    • From the hardcore SS lover’s perspective, SW had audibly more bloom with a warm-neutral tone. Tad darkish balance on top ends mixes well into the rest spectrum. That was one of the greatest tones I’ve ever heard from HD6x0.
    • Details and dynamics were a lot better with SW. This was more noticeable with HP1 stock compared to other headphones I paired with SW. I’m under the impression SW is better at micro than macro, but even if so, SW was clearly more slamming and biting than the control. Maybe not as analytical tho.
    • DX hp out was black but I feel like losing many things. SW was equally black but did not make me feel missing out. In other words, SW can show “righter” blackness to me.
    • Spatial elements are always good with OPT and SW is not an exception. Better layering, better depth, a little wider than the control by all means.

    Sound (vs Zen)
    • Overall I found both amps were excellent in many ways. They really do a lot of things just right (or at least good enough). But I felt Zen was more analytical in good ways and SW was more liquid than the other respectively.
    • SW could also edge out Zen in staging depth and layering. But this is more obvious in HD6XX/HP1. But not so much in the two HFMs I tested.
    • Zen with higher gain setting has more juice to drive Susvara than SW. Frankly I don’t think Sus paired acceptably with SW. But Sus is probably not what this amp is supposed to drive.

    Tube Consideration
    • Stock tubes were not bad. But I found RFT EF184 could really open up things. Marginally improved in every criterion I described above, which together created a very meaningful amount of sum.
    • The loaner amp also came with another set of tubes (Ultron ECC84). I haven’t heard them yet (RFT made me very lazy..), but will spend time this weekend and update back to the thread.

    Other thoughts
    • With the original price of 350-ish usd new, I can strongly recommend to shortlist this for any low-budget headphones audiophiles REGARDLESS of preference/taste/etc.
    • It seems that with the recent parts cost increase, the price was adjusted to $600. Not too bad yet, but I’d find it way more difficult to take SW over equal or cheaper priced amps. Certain clusters (OPT, SET, or 6x0 heads) can still appreciate it though.
     
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    Last edited: Mar 24, 2022
  6. Vtory

    Vtory Audiophile™

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    I was originally going to evaluate how sw51 pairs with ultron tubes, which wasn't successful because one tube was shattered (see the loaner thread for the details). Instead I'm dropping a bit more additional thoughts.

    Addendum
    • White it is not as blooming as extremely warm tube amps, I still think SW makes thing a little wet and bloom compared to any SS implementation. And this synergizes very well with over-damped/dry-toned headphones. I tested one such headphones at the end of the evaluation period, and the synergy was downright fantastic.
    • All my evaluation in the review post above came from Low-Z out. I personally could not find hi-z useful in my use cases. But I agree with others in that it may benefit electrodynamic headphones with lean bass.
    • I also found SW is less demanding in the source quality. I don't say it doesn't scale nor is not transparent. But the matching quality is not as bothersome as the same dac feeding the other amp.
     
  7. Skyline

    Skyline Double-blindly done with this hobby

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    Interesting. I use this amp exclusively with the HD600 and have never tried Low-Z. Can you give a comparison between the two?

    Is the DAC playing a role in this choice or is it purely headphone-related?
     
  8. Vtory

    Vtory Audiophile™

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    Haha I was exactly thinking of hd600. As you may already know hd650 has more bass in quantity and specifically mid-upper bass hump (over 600), Hi-Z makes this even thicker (=worse to me), which was overall too much for my taste. Leaner bass response of hd600 may benefit from hi-z. My conjecture tho.

    DAC can be a factor, but I do believe hp-amp synergy will play more dominant roles. I might be wrong. FYI all my assertions were double checked with 4490 modi.
     
  9. Grattle

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    I only hope to see mine someday. I paid a deposit around November and I don’t think I’ll ever see my amp or get my cash back. I get zero communication, and have zero idea what the status is. This began long ago, not just since Putin lost his mind.
     
  10. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Sorry to hear you're still having problems. Have you tried ZampotechNA to see if they can help with comms?
     
  11. Kolozub

    Kolozub New

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    I think it should be OK soon . I will send you PM that Ruslan sent me few days ago.
     
  12. supertransformingdhruv

    supertransformingdhruv Almost "Made"

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    I’ve heard a lot of chatter about the SW51+ ever since Zampotech popped up on sbaf and started building amps. I hadn’t had a chance to hear one until this loaner. Additionally, this is the first “real” (i.e. not hybrid) tube amp I’ve had a chance to spend time with at home.

    While there were aspects of the sound that I really enjoyed, there were also elements that I did not like.

    The good:
    • The pairing with HD650 was excellent. I’m not someone who likes typically HD650— I find that it feels slow compared to planars— but SW51+ made it feel fast and responsive from the midrange up. I’m finally beginning to understand how people converge on HD650 + megabuck tube amps as their endgames.
    • Staging was as good as I’ve ever heard it on any headphone. Great width, instruments and vocalists felt spatially separated.
    • SW51+ provides a lot of detail. While I’ve heard more detail on headphones before— the Audeze CRBN at CAF comes to mind— I was pretty blown away that HD650 was capable of this.
    The bad:
    • Compared to the LP, SW51 sounded like energy had been sucked out of the mids and highs. Although I definitely heard further into the track, I felt less engaged.
    • The thing I didn’t like the most was the bass. Charitably, I’d say it had a lot of bloom. I found the bass exaggerated and unresponsive, verging on boomy. The guys on zoom had a few thoughts for me on this ranging from “maybe you just don’t like tube amps,” and “that’s just an honest portrayal of what Gungnir A1 sounds like,” to “you can’t judge it on the stock tubes.”
    • LCD 2 was basically a nonstarter. I spent <1 minute before moving on.

    The other:
    • SW51+ seems pretty sensitive to tubes, so if you’re into tube rolling that could be nice. I briefly tried the EF184 tubes that were included in the loaner. There was a noticeable shift in the spatial presentation, which was really neat.
    • There are low-Z and high-Z outputs on the front of the amp. At first I thought high-Z would be the correct one to use with HD650’s 300 Ohms, but the bass problem I mentioned was even more pronounced. I settled on low-Z for the rest of my listening.

    Equipment list:
    • Source: Roon to HiFiBerry Digi+
    • DAC: Gungnir Multibit A1, coax in from source
    • Preamp: Freya S (passive), bal in from DAC
    • Headphone Amps: SW51+, SE in from preamp; Liquid Platinum, bal in from preamp
    • Headphones: HD 650; LCD 2 (briefly)
    Thanks to rhythmdevils for & Cooper12 for making this loaner possible! I had a lot of fun.
     
  13. ergopower

    ergopower Friend

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    First, thanks very much to @rhythmdevils for organizing this tour. I've been pretty curious about this amp.

    I listened to 4 amps vs SW51+. Valhalla 2, Vali 2+, LAuX (single-ended) & Gilmore Lite Mk2
    Valhalla 2 was not stock, 6H1N input tubes & 6H6N output tubes. I bought this used here and those were tubes the previous owner included and recommended. I’ll be damned if I can find the box it came in, there are stock tubes in there. Vali 2+ also not stock, used ECC84 tube. This I A:B-ed against the stock tube a while ago and much prefer w/HD6XX.

    Chain was laptop w/Spotify or YouTube > iFi Micro BL DAC-only > amp > HD6XX
    I had done a little DAC shootout prior to SW51+ arriving. Switching tubes in the Vali 2+ was a definite improvement, but still some over-emphasis in 100 – 200Hz area. Knowing ModiMB is on the warm side, I swapped it for the Burr-Brown D-S DAC in the iFi Micro BL which has been pretty well regarded here – mmm, worthwhile improvement, bigger change than I would have thought you could get from just a DAC swap. Probably can do better yet, need to investigate.
    I also listened to an Elex & ModiMB V2. But I found it hyper-realistic if I listened after the HD6XX, even if the next day and I don’t think my impressions would have any value. I use Elex off and on; it is a much different presentation than HD6XX - kinda fun & exciting but ultimately more fatiguing. @dematted made some observations about Utopia here that are very in line with how I feel about Elex.

    My first comparisons are always how well a system renders lower male voices and by default I also make judgement on lower bass performance. My references are Kenny Chesney/’Hemingway’s Whiskey’; Guy Davis/’Come Back Baby’ et al; John Prine/’Ain’t Hurtin’ Nobody' et al; Lyle Lovett/’No Big Deal’; and Frank Sinatra/’Fly Me To The Moon’ et al. Listened to the Vali 2+ first, since I use that the most lately. Switching to SW51+, there was definitely more bloom to those voices, especially Chesney; and the bass overall to me was over-emphasized. So I tried the EF184 tubes, and stuck with them the rest of the way.
    NOTE: the stock tubes have a very slight hum. EF184 do not but hum was too low to have any effect on what I heard
    Bass overall w/EF184 was tamed; all voices sounded really good; and there was a little more clarity up top. Now we’re talking. Slightly better control than Vali 2+. LAuX very close to SW51+. Lite Mk2 a touch behind. Valhalla 2 was disappointing, too much bass bloom and chestiness (although to be fair, see Spoiler above); and it was shown the door after this test. Same for the Lite Mk2 – easily better than Valhalla 2, but seemed like it was always gonna be a little behind LAuX, so not worth the time.

    So now just listening to music. I went through a lot of genres – Blues, Rock, Punk, Pop, Big Band, Opera/Classical. Some very good, clean recordings; some where I just wonder WTF was the producer thinking.

    In the end, with HD6XX, I rate SW51+ the highest, and the best amp I’ve heard so far (no experience with Big Boy toys, though). Really good tonality throughout, nothing seems over-emphasized. Nicely smooth, but still engaging. You’re still aware that HD6XX is not great down low; some over-emphasis between 100 – 200Hz, rolls off too much below that, and does not have the air of any number of other cans. But still a great listening experience that can have you staying up way past bedtime. The other thing I notice about this amp is the headstage. I had read comments in several others’ reviews, and I kinda dismissed it because I also listen a lot to speakers, and its 2 different experiences in terms of staging. But where I hear the 3 blob effect with the other amps, SW51+ is more even across and outside your head. A good track to show this is Keb’ Mo’/’Soon As I Get Paid’. Listening on speakers, it’s a decently wide soundstage, but only barely outside the speakers if that. On the other headphone amps, the guitar on the right really sounds off on its own, out at your shoulder. SW51+ keeps a connection with the rest of the band. Again, all of the above is with the EF184 tubes.

    The eye-opener is Vali 2+ w/ECC84. SW51+ sounds a little more controlled/more grip, slightly less bass bloom. But I don’t see the value for me personally w/HD6XX in upgrading.

    LAuX also is close behind SW51+, but it ought to be considering price. It is as good down low, but there are tracks where I hear the SW51+ as being that bit smoother, in a good way. If I were in the market for a new amp for that kind of money, SW51+ if I’m just using HD6XX. Other cans might make me judge differently.
     
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  14. dematted

    dematted Friend

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    Been revisiting this really lovely amp since receiving it today from @ergopower. Using my ETA Baram and HD540 600 ohm. I think the output impedance is a bit too high for Baram - makes it sound a bit mushy and fuzzy. With the HD540 600 ohm, it's been fun A/Bing with the ECP 3F. The 3F gives the 540 a better sense of tactility, fleshes out the bass a good deal, and makes everything sound more refined and spacious, but it can't quite seem to match the sense of immediacy and microdynamics in the mids that SW51+ provides. The biggest thing I miss going to the SW51+ from the 3F is the sense of tactility and weight the 3F provides - by contrast the SW51+ lacks some bass extension and sounds a bit woolly there. Will write more once I do some more listening, but I think for certain genres of music I might legitimately prefer SW51+ to 3F with the HD540. Maybe not surprising, since 3F wasn't really meant to power super high impedance headphones, but still pretty amazing considering the price difference between these two amps.
     
  15. dematted

    dematted Friend

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    It looks like loaner gear is once again going to prompt a bit of gear reshuffling for me.

    I thought I could be done with tubes with the ECP 3F. Now, the 3F is a wonderful amplifier with really amazing reproduction of the nuances of bass notes and an expansive stage that I've never heard any other SS amplifier replicate. But it doesn't quite reproduce the sense of forwardness and realism to mids, particularly vocals, that a good tube amp like SW51+ does. It's funny because in many respects, moving from the 3F to the SW51+ is a noticeable degradation in things like separation, clarity, and the overall sense of cohesiveness and refinement of the sound. Things just sound a bit muddy and fuzzy moving from one amplifier to another, and so naturally I had a bit of a negative reaction when moving from the 3F to the SW51+ loaner on my Baram, which tends to be fairly revealing of downstream components.

    But after my ears got adjusted a bit, I found that I couldn't really go back to the 3F. The mids just sounded a bit withdrawn, and vocals in particular lacked the fluidity, richness and realism that they had with the SW51+. Instruments on the SW51+ also tend to pop out just a bit more, and music sounds like, for lack of better terms as if it has more emotion and soulfulness to it. And I don't think I'm missing much in terms of microdynamics either, which if anything sound a bit more exaggerated on the SW51+.

    That being said, having these two amps side-by-side does really show off some of the weaknesses of the SW51+. Bass in particular, which I never thought was a strong point of the SW51+, is really lacking. There's just not much extension, and the bass that's there isn't particularly tight or hard-hitting. There's a pervasive feeling of looseness here, and also a lack of definition. In comparison to the top-end of the 3F, the highs also lack some sense of sparkle and air and sound a bit closed-in. It also reveals the fact that this is definitely a -colored- amp, and by that, I mean one that's mid-forward. Upper-mids in particular seem a bit bumped up with the stock tubes. But I guess for me, I'm willing to trade in all these problems with the sense of realism in the mid-range that tubes bring.

    Thanks to @rhythmdevils for adding me onto this loaner. Was nice to hear this classic SBAF amp again.
     
    Last edited: May 6, 2022
  16. jaker782

    jaker782 Friend

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    I'd like to give a hearty thank-you to @rhythmdevils for taking the time to set-up this loaner and for the opportunity to participate.

    Unfortunately, life kinda got in the way when I had the SW51+ on loan so really didn't get a chance to compare directly with other gear. During my limited time, I focused on listening to it with a stock HD650 and my ETA Gen G 1.1 using both a Fiio M17 dap and Modi 3 as a source.

    I thoroughly enjoyed the SW51+ with the HD650 as it really seemed to compliment the tonality of the Senny quite well. To me, the star of the show with the SW51+ are the liquid mids and subtle SET warmth that gives vocals a nice, textured quality that is very engaging. As you can imagine, this presentation really doubles down and enhances the already superb midrange of the HD650. The SW51+ really takes the best part of the 650 and magnifies it. The elephant in the room with this amp is the bass quality. While satisfactory, it lacks punch and just doesn't slam at all. It just kind of putters along with a soft and loose quality that just isn't very satisfying. It is reminiscent of a fart that you try to let out low and slow with restraint rather than just letting it rip. Since the HD650 also lacks low end extension and impact, I think this quality in the amp is kind of masked and really isn't as noticeable with the Senny. The 650 and SW51+ really is a fantastic pairing.

    While the HD650 provides wonderful synergy with the SW51+, ETA Gen G was a different story. Gen G is much more alive, attention grabbing, and can really slam with impressive impact and extension. This simply did not jive as well with the SW51+, particularly when it comes to low end performance. The slow and wooly bass of the SW51+ becomes quite noticeable on the Gen G and diminishes the low end grunt that makes that headphone so enjoyable. Not sure if the higher output impedance has something to do with it, but SW51+ just seems to place a soft pillow over the Gen G sound. Don't get me wrong, the liquid smooth midrange of the SW51+ does sound pretty damn good with Gen G as well, but the diffuse low end and lack of treble extension seems to add a sort of veil to the Gen G drivers. It is like taking a step forward with the mids but two steps back everywhere else. I will say the pairing is actually pretty decent if you want to tame the liveliness and take the edge off, but I have the 650 for that so why bother?

    So in summary, I do feel SW51+ is one of those magic amps that really complements the HD650 quite well and may be my top choice if your main driver is any of the Sennheiser variants. At the original price, I'd say it is a no brainer, but even at the current asking price, it is a strong contender for sure if you are looking for a bit of that tube magic with your Sennheiser's.
     
  17. ergopower

    ergopower Friend

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    Did you give the EF184 tubes a listen? As I heard them, they don't extend bass any deeper, but they do sound tighter.
     
  18. jaker782

    jaker782 Friend

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    I did and agree with you. I just didn't think rolling tubes with this amp provided a noteworthy difference, especially since I really didn't spend enough time comparing tubes to draw any definitive conclusions. For that reason, I chose to leave the tube rolling out of my impressions.

    One thing with this amp that I actually really like based on this experience as well as when I previously owned an SW51+ is the stock tubes sound good and you aren't really missing out on much if you choose not to roll tubes. Tube nervosa need not apply!
     
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  19. ChaChaRealSmooth

    ChaChaRealSmooth SBAF's Mr. Bean

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    SW51 Impressions, 2022 style

    I always liked the SW51. Those who know me well will know that from a purely sonic performance standpoint, I think there's a case to be made that the SW51 is worth it even at $1000 USD. My opinion has not changed; I still think that for the $600 + tax + shipping, I think the SW51 is absolutely worth the cost and is still a steal (even though it is unfortunate that inflation and the going-ons in Russia has driven up the price).

    Sonics

    Anyone who has read SW51 impressions and seen the measurements know that this amp will make objectivists immediately go on life support once they see the THD numbers. If this is you, stop reading now and go away.

    Contrary to the measurements, the SW51 presentation is overall more on the straight-shooting side of the tube amp spectrum. Basically, think the opposite of the Feliks OTL sound; the SW51 is more tight than bloomy, punchy rather than relaxed, and clean rather than romantic. That's not saying it doesn't sound like a tube amp; the 2nd order harmonics shown in the measurements are definitely audible and it has a bit of wetness in the timbre that screams TOOBS. To use another well-regarded OOP amp as an example, SW51 sounds more like solid-state like than ZDT Jr. There's a reason why I say the SW51 sounds like the DSHA-3F's little brother, except with tubes.

    If anything, the SW51 comes across as slightly mid-centric, almost (but not quite like) the Schiit Aegir and Asgard 3. It is a bit rolled in both ends of the spectrum, with the low bass notes not quite coming through and the treble missing the last octave. The bass itself is also is not what I'd call a strong point; it's not super defined or delineated. I wouldn't call the bass wooly or soft, but it has a bit of that old school tube stereotypical sound. Those last two points are really the only real factors stopping the SW51 from being a big boy tube amp ass-beater, but the weak points aren't really that bad; just something to keep in mind.

    In terms of resolve, the SW51 is probably about 70-80% of the way there to the DNA Starlett. This is not a joke; the SW51 is that good. Textures in the mids and treble is absolutely spot-on even through its tubey sound and 2nd order distortion.

    Dynamics are quite good, especially the micro; the SW51 is very delicate on its feet and reproduces nuances very faithfully. Those looking for fire-breathing slam and huge macrodynamics need to look elsewhere though; the SW51 is much more along the lines of the DNA Starlett where its more stately and refined.

    If you don't understand much of anything above, basically if you don't want to buy a big boy DNA amp, buy one of these.

    Headphone Pairings

    Most dynamic driver headphones will work well with SW51, with the exception of things like the ZMF Atrium which need more power to really come to its own. I don't recommend planars at all with SW51.
    • Focal Clear (OG because I hate the MG): Still good, just keep in mind that the SW51 can't fully take advantage of the bass that the Clear can potentially have. However, very good in the other ends of the spectrum. I recommend Clear over other Focals with SW51 because the Clear is a bit more laid-back.
    • Sennheiser HD600: IMHO this is the headphone to pair with SW51. Very good synergy and this combo will blow away systems many times its price. Anyone who says otherwise is kidding themselves and doesn't understand the magic of this little tube amp with inexpensive but great Sennheisers. You won't get better mids than this under $1k.
    • ZMF Verite: Yes. If you like the Verite's sound then I find it hard to believe that you can do much better than SW51 with the Verite for midrange amps.
    Keep in mind the SW51 has a low Z out and a high Z out. I would say play with the two outputs with your respective headphone to see which one you like better; the user manual recommends low Z for 32-100 ohms and high Z for 100-600 ohms. But again, you can and should play around with this. FWIW I didn't think the amp sounded better from either output; I think this is more of a matter of pairing and preference (I liked the low Z better with JAR600).

    Conclusion

    For me personally, I consider the SW51 the best midrange amp hands down. If you primarily use HD600/650, then my recommendation is to buy one of these and only buy another amp if you're going to upgrade to a DNA Starlett or Eddie Current. However, if you primarily use Focals or other headphones, this is again a matter of synergy, but overall I still think you should give this amp a shot.

    I have to also talk about the price again. It's very unfortunate that the price has gone up, but there's just no way around current world economy and the Russia situation at the time of writing. Yes it sucks for the consumer, but considering what you get for your money, I still think it's absolutely worth it (I stand by saying that the SW51 sonically is worth $1k).
     
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    Last edited: Nov 2, 2022
  20. caute

    caute Lana Del Gayer than you

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    Imma have to stand on the shoulders of giants for this small note on the SW51+, which was loaned to me for about 3 weeks from a Super Friend:

    The microdynamics, inner detail, and mids-to-treble transition, the sustain (and decay) of the SW was off-the-charts good to me, as well as its spatial layering, as if itsy bitsy pieces of sonic information were writ large across the entire FR (except for maybe the lowest octaves of bass), and seemed to "breathe", and sometimes even "glow". It is a tremendous amp, even at its current MSRP and it was a rip roarin' steal at its former price.

    Compared to the Piety:

    The SW had more microdetail, smoothness (not just in the treble), lusher midrange (with Amperex tubes), and a much better sense of separation, notes seemed to linger in front of my forehead and behind my skull, not sure if this is what is meant by a "wraparound" stage, but it seems dam close.

    Staging was truly a delight, as was the inner warmth, where the Piety had more "macro warmth", that amp is boozier (in low gain), and it's a toss up as to which one is wetter, sometimes I thought it was the SW, sometimes Piety (let's just say I had a hard time distinguishing between these two amps on rapid a/b switching.) but overall it's a step above the Piety in almost every single area except for slam. That's the one thing I missed from the Piety when extensively demoing the SW.

    This is a wholeheartedly recommended baby SET amp for 6x0heads; I have heard some call it a 6x0 specialist amp, and I would have to agree (the JAR800 family did not get along with this amp, methinks it's due to lack of grip on the larger drivers and lower power in general).
     
    Last edited: Mar 22, 2023

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