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Oblivion | UltraSonic Studios

Discussion in 'Headphone Amps (full-size)' started by Maxx134, Mar 22, 2019.
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  1. Maxx134
    Oblivion | UltraSonic Studios
    Builder: @SonicTrance

    Schematic designer: @MrCurwen

    True & ideal hybrid amp. True Implementation of Tubes for voltage, and solid state for current. Truly modern design choices of mating circuit designs like CCS & Gyrators effectively to reducing parasitics to the point where component quality does not interfere with, or become a factor for optimal sound(!)
    That perspective is a huge game changer in itself.

    Gone are the old-school tube designs of which mostly ALL of current tube amps are still using which are ancient, old, and non-creative. Gone are the days of heavy expensive output Transformers and huge expensive capacitors. Gone are the headaches of worrying about super expensive parts quality upgrades. Gone are the aggravation of expense in endless tube rolling to find the best match for the amps with expensive tubes!

    What I am saying is that this ideal modern mating of Solid state and tube is a game changer not because of what it uses, but because of how it is implemented.
    Thanks to @MrCurwen for both the design and the unique perspective of design choices,
    We have a resolving amp with high transient speed and high END GAME level transparency, due to reduction of parasitics and component choices which use parts to their best design parameters.
    You see I slipped in the word "end-game". This term is not easily thrown around and so you now already have an idea at what level we are playing here.
    This is not just another tube amp, or just another hybrid amp using two amplification devices as a "novelty".
    This amp to me, defines the proper use of the term hybrid amp and finally gets it right.
    No dumb leds or special circuits thrown in, just for novelty to impress.
    Only the music produced is what is meant to impress.

    My type of review a bit unsual as it does not follow like colorful ambiguous reviews which lose the reader in dumb music selection attributes.
    This to me is placebo to reference a review to itself and nothing else.
    You have no "ruler" to base your impressions on.
    So my review instead deals with music selection as a secondary and non-issue.
    Only amp qualities are compared, TO OTHER REFERENCE END GAME AMPS(!).

    Not many, but the primary point, is to enough to gain a good perspective and feel of what I am talking about.
    I have been testing/modding-upgrading/listening to other expensive amps in $4k range.
    Namely, an upgraded Eddie Current Aficionado (EML mesh plates & cap upgrades), Cayin HA300, Benchmark HPA4, and a Stax009/KGSSHV Carbon combo setup, Woo Wa33, and some speaker amps are among the units tried/comapred & mentioned, only in order to gain a perspective of the quality level we are at.
    As for source gear, they were Yggy A1 & A2 and Holo Spring

    Aficionado audio upgrades I put in:
    After much trials, the stock Nichicon cathode caps in both driver and output stages were upgraded to same model Nichicon KZ, but higher voltage spec for lower ESR & faster transients, from 25v&50v to 50v.
    Coupling caps upgraded to best Jupiter copper foil.
    Output tube sockets rotated 180degree & tubes upgraded to EML mesh 2A3. ($1000)
    Input tubes upgraded to LM Ericson 2C51/396A
    The total upgrades optimized the Aficionado superior to stock, and I considered it as a preferred reference over the others for a time.
    So this version of the Aficionado was the main comparison to @SonicTrance new amp Oblivion.

    The topology of Oblivion is transformer coupled (parafeed) balanced amp with open loop (no NFB). SE input stage with balanced CCS loaded source followers that drives the output tube grids. The grid drivers relieves the input tubes of any drive duty. Tubes do voltage amplification and FET’s supply current. Tubes do what they do best and FETs do what they do best.

    The LTP output stage is force balanced through the CCS tail. All tube anodes are gyrator loaded. Regulated B+ and B- so the voltage doesn’t fluctuate with the signal.
    Since Oblivion is open loop (zero NFB) and constant current draw it recovers extremely quick after high transient peaks. That why there's no need for many watts of headroom with this topology like in many other amps with cathode bias and NFB.
    Input tubes are 6AT6’s
    Output tubes are EL81’s
    Here are the pics of this beautiful amp.
    Notice how this unit looks so professionally made. Member SonicTrance certainly knows how to make it look extremely well finished.
    The volume is very smooth and the selector feels especially solid.
    That metal XLR is a rarity and is very satisfying plugging into.

    If meat is the main part of your meal, this review gets right to that as best I can.
    To the few manufacturers of these mentioned amps, as I will now remind all to put this review in perspective, that we ARE discussing ALL TOTL Elite “summit-fi” quality amps, not mid-grade stuff, which means final choices are all at a level of personal preference... They all have their strengths which I will try to describe as well.

    Here are the main qualities of this amp I will state in my impression quotes:
    These will be laid out in “note taking” form, as I have taken many notes while doing comparison, listening, and discussion with others listening at same time.

    This “Oblivion” amp has transient speed, immediacy and openness. Holographic organic imaging tube qualities without coloration/harmonics of tubes.

    Here are my subjective impressions:
    The strongest quality of the Oblivion amp was the soundstage. The oblivion was properly laid out, compared to the(upgraded) Aficionado, and a bit more depth resolve than the Stax009/KGSSHV Carbon setup.
    Yet the Stax009 had a bit more pronounced detailing.

    The Oblivion had the best soundstage and was able to make the Abyss Phi sound the most liveliest it ever sounded..
    It made the Aficionado sound a bit colored & splashy.. Which on hindsight would be logical since it is a traditional tube designed amp.
    All three above mentioned amps all had super high level resolve, but the presentation was so well done by Oblivion, that it made other amps appear skewed in the image presentation from absolute accuracy.
    In comparison to the Oblivion, the Stax was a bit exaggerated in raising the detail levels, and had a bit less depth resulting in a closer image.

    The Aficionado was a bit exaggerated in tube color (as expected), and image presentation (actual “shape” of the soundstage boundaries to be curved). Only in comparison could you perceive that the excellent sounding Aficionado was not as accurately laid out as the Oblivion, both horizontally and in depth. Just that bit skewed enough to slightly notice in comparison, otherwise these things would not be easily detected at all. Certainly not without comparison and critical listening.

    Remember that the Aficionado was upgraded to the max with both internal upgrades and $1000 output tubes.
    Regardless, all three amps had über high and true “end-game” level resolve. Just the presentation was different.
    Oblivion amp just had outstanding and unbeatable image rendering both laterally and in depth.
    IMO, out of all these superior amps, the Oblivion kept best soundstage presentation accuracy overall, with a liquid holographic and color free sound, with SPEED. The transients, being noted as given attention in the design, showed it in playing a large part in giving the harder to drive Abyss PHI more liveliness.

    I always thought I preferred euphoric tube color until I heard the qualities of musicality, delicacy and holography, without any tube richness or color. This is what Oblivion amp portrayed. The woo wa33 also was compared side-by-side with the Oblivion, and it also portrayed this less ”tubey” nature, while the richest tube sound came out of the Cayin HA300, which to me was the most well done ”tubey” amp as far as euphoric tube sound went.
    My friend said the Oblivion most reminded him of the both the KGSSHV Carbon and the Viva Egoista845 amp together, in terms of spaciousness, speed, and transients. I agreed from my memory of the Viva845 I had heard earlier few days before.

    Musical comments:
    Initial first impressions...(with HD800)
    Testing piano it is playing so clean... No tube euphoria but with the delicacy and realism that solid state does not give...Actually it does have an immediate and very lively aspect.
    Nuance and bass string pluck and bass into an HD800 is pretty impressive, it also seems like a smooth amp, while retaining top end clarity. The HD800 is good at picking out differences there.
    Piano has holography & nuance so that is very telling.
    Live Audience applause is very individual, another classic sign of high level resolve.
    Image overall sounds a bit larger than usual.
    Background is dead silent I thought it was broke as it is so silent!

    Later, the main headphone we tested the Oblivion was with was the Abyss Phi..

    The first time that the Abyss Phi reached Stax level sound realism was with Oblivion.
    The Aficionado had high realism as well, but not as alive.
    Not as clean in harmonics, or expansive in image in the lateral plane ...
    Oblivion actually eclipses the Aficionado, which I personally modded to be superior than stock.

    My friend and I were both amazed and in partial disbelief of the performance of the Oblivion!
    It was a bit hard to accept the realization that this amp was performing at such high a level.
    It really was not expected Oblivion to even come close, let alone SURPASS the Aficionado...!
    For me it was a surreal and funny moment to realize you cant believe what your hearing..

    Transients and sonic image were amazing on the amp.
    Realism, refinement, effortlessness, neutrality, solid presentation, timbre..
    All outclassed the Aficionado for me(!).
    Sounded a lot like the stax009 setup, but with a better soundstage field.
    Made the Aficionado sound a bit warped (rounded) in soundfield extremes, with also a more colored image(tubes).
    The Aficionado's realism was there in spades, as this was end-game level, but for me the presentation of this realism was skewed in the soundstage.

    Both the Stax009/Carbon setup, and Oblivion presented the image more realistically to me, while Oblivion actually pulled ahead in both the horizontal plane, and in depth field clarity.
    I realized that the Stax setup was sounding like it exaggerating and compressed forward some layering of the detailing (in comparison), and that is why Oblivion was actually more true to the source.

    Using the LCD3 was actually very efficient, and it did extremely well.
    The LCD3 in bass was a bit more articulate than the Abyss, although noticably less impactful, and it's(LCD3) upper range was less resolving overall than the top headphones we heard in past.

    The HD800 was phenomenal with the amp.
    Nothing lacking except bass level, while bass nuance matched the stax009.
    The Abyss phi bass, although powerful, was not as articulate or resolving as both the Stax & the HD800.
    The LCD3 came close but was not at the level.

    The Oblivion is clearly and unmistakably superior to any tube amp or hybrid I have heard so far. The openness of stage and clarity is on another level than anything short of a Stax setup.
    The clarity and dynamics combined with superior soundstage is, to me, above any amp I have heard(!), with exception of an EC Studio which I would need to direct compare to in future.
    I really cannot find fault in Oblivion.

    About the other amps:
    Subjective notes:
    The modded Aficionado I upgraded eclipsed the Cayin HA-300 rather easily, but that Cayin is way more (tube)euphoric in sound than the Wa22 or the more powerful very transparent wa33...

    Don't get me wrong, I like the wa22 and think it’s great, but it’s still mid-fi level in stock form, while we talking even higher end-game level sound...

    My own heavily tuned LDMK8se that I put thousands extra money in, did not fully reach the (modded) Aficionado performance level, (which was a "reference point" for a while)…

    The woo wa33 very easily reaches end-game level, but itsway less harmonics are not a beautiful as the Cayin HA-300, although the wa33 was higher in resolve...

    The woo wa33 surpassed the "upgraded" (modded) Aficionado in power, and was less colored but also less enjoyable.

    Oblivion vs Woo wa33 using Susvara:
    Subjective Notes:

    Oblivion wins slightly in soundstage, instrument separation, and width...
    Both are a tie in clarity.
    Woo wa33 win in power which gave it very slightly better low end punch hardly detected.
    In a separate comparison, the Aficionado has slight thicker bass than these two.
    The Oblivion did not sound any worse than the woo wa33. In fact the whole time it actually sounded cleaner and slightly more distinct in instrument separation. Probably by 3-5% more but still noticeable.

    Remember to take this in perspective of so high a level that your headphones can alter such differences.
    Third comparison at that time was a “First Watt” speaker amp which had a different, more organic tonality overall. Maybe thicker which made music more palpable for the Susvara, which was main headphone used for this test.

    The Benchmark HPA4, after a 3week burn in, was the only commercially sold (not DIY) solid state headphone amp that I heard to reached the level of tubes in soundstage, similar to what the Carbon did to the Stax009.
    I mention this because the upgraded Aficionado was preferred over both the HP4 & both over the Cayin HA300 in soundstage and clarity (respectively).

    So why do I tell you all this background info of other amps & headphones, when your just wanted to know about the "Oblivion"???...

    So that you now will know just what level we talking about with the Oblivion.
    From my observations:
    *It is a notch ABOVE the reference moded Aficionado overall, in soundstage placement and solidity of realism.
    *It is the only amp I tried (so far) that pushes the Abyss Phi to sound better (more lively) than I ever heard it before.
    *It is only amp I felt not need any modding (like my LDMK8se) and so I purchased it for my own, as reference amp.

    So far I consider it at total end-game status, at a less powerful level than the EC Studio.
    I consider this a new breed of design philosophy and a no brainier at the price it beats out multi thousand dollar amps...

    The Oblivion, being a "true" hybrid (not just having tube parts for the sake of having them), it has the best of both worlds.
    The most accurate soundstage for me, so full holographic sound of a tube amp, plus having the very clean (yet non-sterile) sound of a solid state amp.

    I have rolled the driver tube on the Oblivion to detect an ever so slight difference in "air" but basically you’re getting a "EC Studio" neutral sound with the life and holography of tubes.
    Bass is present but not thick or "fat" like some tube amps can get. The transparency, transient speed, and clarity is what gets you.

    I consider it my current reference.
    I would only look for more power (EC Studio) if I had a Susvara, BUT if I had a Susvara, I would not bother with a headphone amp as it does its best with an actual speaker amp like the “First Watt” (like the HE6 needs)..
    I preferred the Susvara over the Stax009/Carbon in that configuration.
    For all other headphones, the Oblivion, or the higher model SonicTrance has to offer is the obvious choice for me.

    I personally, am very content with the Oblivion amp.
    It is unbeatable for a transparent reference amp, unless I wanted a thick syrupy or less resolved amp.
    That’s my honest subjective opinion and I would not suggest something that would make me feel bad about suggesting.
    It’s not about money for me, but the sound and practicality combined.

    I “could” also suggest to you the Stax 009/KGSSHV-Carbon setup, as alternate choice of “end game” gear, but that requires many more thousands which crosses my limits of practical suggestions, as well as not sounding as layered to me.
    To some, like me, I find the stax009 having the speed of the RAAL ribbon (which I also compared side-by-side to the mentioned stax009 setup), but just not as natural sounding(a bit artificial), especially in the bass, while the ribbon was natural and “perfect” sounding, except it just doesn’t cut it for me in bass, so I will stay with the more satisfying traditional planars and dynamics, which the Oblivion handles perfectly..

    Anyways the Oblivion amp is currently what I could easily recommend in good conscience. Especially with a wide range of headphones since it was tested with the most demanding and reveling of headphones just mentioned.
    Think of SonicTrance "Oblivion" amp as a colorless neutral, yet wonderful soundstage amp, where the joy comes not from the euphoric color, but instead the greater involvement of noticing everything in the stage without color.
    You just instantly recognize the amp as sounding more true..
    There is a feeling of majestic certainty in the soundstage presentation and timbre.
    We talking about accuracy in presentation.

    Price for Oblivion is USD 1450 and USD 1600 with speaker outputs

    Contact @SonicTrance. He also offers an all balanced version called Citadel.

    Considering what I have compared it to, I consider this amp to be a ridiculously great deal.
    Last edited: May 15, 2019
    nick n and kvik like this.
  2. Maxx134

    Probably will use for pics

    Edit more pics of production versions:





    Most consumers will not know what a CCS or a gyrator is and how it was implemented in this design.
    The implementation of this topology should not be underestimated, and this amplifier should be an example of how manufacturers should modernize thier designs.

    I think a link to the other DIY thread of member SonicTrance would help those understand this topology:
    Last edited: May 5, 2019
    biglazymoose and nick n like this.
  3. Maxx134
    one more
  4. MrCurwen
    Thanks for the comments.

    Some (not a lot) more power could be had, but I myself haven't had need for it.

    This is the SE input section version if I'm not mistaken, it has a touch of the old tube sound compared to the fully balanced version. I prefer the SE input stage for reasons of laziness, since I build all my own stuff, but for buyers it's a matter of taste. Both are extremely transparent in my opinion.

    Did you try this amp with speakers? What were your impressions, how good was the power output?
  5. baronbeehive
    Thanks Maxx for the…. long awaited!!!... review, we've been licking our lips for too log LOL!

    Your method of comparing with known top level amps is very pertinent for me, I found it a good method for detecting differences in the modded Little Dot MkVI+ for instance. The trouble with just reviewing music is that there is no baseline, and it's just an endless rehash of opinions which doesn't necessarily bear relation to improvements in technology for example.

    This amp appears to do the business, ie. it does what I would expect from a TOTL amp in terms of soundstage which is the one thing that I would expect of an end game amp. The design philosophy is obviously proven in focussing on transient recovery rather than out and out power. This feature benefits from regulated PSU and balanced topology, in other words some thought went into the design, it was obviously not just thrown together, but each of the design goals was implemented in order to work together effectively to provide an up to date solution to age old problems in tube design.

    The other thing is a definate decision to use hyrid components, tubes for voltage, FET's for current, etc. where each works best. I really agree with this approach and see no need to stick to the age old methods when you have modern solutions which work better. It was a while ago now that I decided that I no longer preferred the tube sound per se, and went for transparency rather than thick euphoric sound, in my decision on what components to use for modding, tube types etc. and I definately prefer more realism now, together with the holography that tubes still can give.

    Thanks for highlighting the positive features of this amp, by SonicTrance, designed by MrCurwen, in your interesting review. These are exciting times in amp builds, bringing together the best in the new and old.

    The only downside I can see…. no more tube rolling... well I wasn't really into that anyway...honest!!

    I look forward to seeing how the all balanced design of Sonic's other new build amp, the "Citadel" I believe, can improve yet on this Oblivion amp!
  6. SonicTrance
    Citadel will sound a bit cleaner. Like MrCurwen said, the SE input stage in Oblivion gives the amp some of the old tube sound. In Citadel that’s completely removed. I wouldn’t call one better than the other. It’s a matter of taste. Citadel is more complicated to build and requires a larger chassis too.
  7. SonicTrance
    There’s no more needed. The EL81’s are biased at -23Vg, 180Va, 17.5mA Ia. B+ is 350V. If I bias any hotter than that would require larger heat sinks and more powerful fan. Just wasted heat anyway.
    Last edited: Mar 23, 2019
  8. Maxx134
    I haven't as I had been moving location but everyone keeps asking me so I will try and post in reserved post.
    Tube rolling is highly addictive and expensive hobby, and once you own expensive tubes its hard to et them go! lol.
    I prefer the very lightly done aspect of this amp driver stage which is barely noticeable.
    Good point. At this current level of transparency, the elimination of the very slight driver tube coloring (without loosing tube attributes) would amount to a "preference" type choice.
    Let me know if you want post anything in my reserved post . I'll probably put future links there .
    I have noticed it stayed cool in AC room, but got warm in my room after a few hours.
    Agreed about the power. The only headphone that extra power would be beneficial for is the Susvara. This amp did very well with it regardless,
    I forgot to mention the fan it has is running silent and well controlled.
  9. SonicTrance
    Yeah, it gets warm and that's ok. Less heat is always good though. I've chosen a large 200mm fan that's very silent just to get the air moving inside the amp. Silent is key here for me.
  10. joseph69
    Does the Citadel at $1600.00 USD share the same aesthetics as the Oblivion?
    BreadMaster likes this.
  11. SonicTrance
    The prizes mentioned above are only for Oblivion. Citadel cost $400 more, so $1850 stock or $2000 with speaker outputs and selector switch.

    But yes, the aesthetics will be the same but with a 100mm deaper chassis. I'll most likely use octal tubes in Citadel (EL36 and 6SL7)
    Thenewguy007 and joseph69 like this.
  12. Maxx134
    Hey guys I have been meaning to update with some more comments on usage with TOTL headphones.
    I brought my Oblivion amp to test with Susvara a week or so ago..
    We also tested it against some speaker amps.
    Last edited: Apr 18, 2019
    BreadMaster likes this.
  13. joseph69
  14. Maxx134
    Ok, so here are my subjective observations..
    Sometimes I write like its set in stone, but I don't mean to be that way.
    I enjoy much gear and yet I never had any troubles coming to conclusions on gear and thats why I write in the wat I do.
    Its important to note that opinions would vary due to real differences in everyone's ear shape & canal.
    My subjective opinions are usually always in line with general consensus of threads over time.
    Therfore I am quite confident in my assessment yet I just want to stress that it is still my "humble" opinions as I usually tread on controversial topics as I reach my points..

    Most "headphone" amps will show their distortion on the Susvara rather easily, if you just blast them past the volume dial's halfway point.

    No one usually does this, but its easy for the Susvara to show the headroom weakness of an amp, by going into this "uncharted area" that most amps don't go. .

    I have done this with a few top headphone amps at the last Canjam with the Susvara, in order to guage a specific amps headroom and also "how" it handles and sounds with such a load.

    They all pretty much started to fail past at 2/3 of their max volume with the Susvara.
    Even the nicer ones (like the sweet violectric Niimbus) succumbed to this deficiency.
    To balance this subjective point, normal listening levels were usually at least halfway point on most headphone amps with Susvara.

    The amps also sound different when pushed to max volume (distortion)on a Susvara..

    This was an unscientific, but very effective and simple test to do.(quick blast with Susvara)

    And lets get it stated that almost ALL "headphone amps" will run out of gas on the Susvera at high volumes.
    This is why many users feel a speaker amp is more ideal.

    So enough blabbering right?
    How did the Oblivion do?

    The same strong points of this amp still prevailed.
    The authoritive soundstage, and especially clarity was its strong point, and surprisingly way past normal volumes.
    Not half, not 2/3, not even at 3/4 volume turned from max volume. There was there no sign of stress.

    The Susvara was handled excellently, and the headphone did not get the better of the amp(!) when past halfway point.

    On most headphone amps it was so easy to hear and describe the distortion at high volumes.
    Not so easy on this amp.
    The oddity of this amp is the lack of distortion, and the effect at higher volumes.
    You had to go past 90% of the volume, to notice the type of effect it has on the sound.
    It sounded as if the bass impact stopped short of its fullness of hit, like a slight soft clip, yet still without any of the normal type of sound of "distortion" you would expect of an amp. No dirty sound. It stayed clean overall.

    Remember this post is meant to be realistic but not practical. Thats why I intentionally forced amps to "real world" maximum volume for observing effects.
    Even if you wanted ear-bleeding, head-banging EQ'd bass, you still wouldn't go past 2/3, let alone 3/4 turn.

    At 3/4 turn on the Oblivion with the Susvara, I could blast only for a few seconds as it was too much for my ears.

    The main trait of this headphone was the clean quality of the sound.

    Ok so what about the speaker amps?
    Well, they both could push the Susvara to more scary impacts, but in comparison, I was just very pleased that I felt I didn't need that with the Oblivion amp.
    It had enough punch.

    So, in the picture, the amp pictured below sounded really sweet with Susvara. Dam nice.
    It was a BK ST-140 ( old school amp), yet the Oblivion had more clarity and soundstage (its strong point).

    The other amp I listened to that day, was an integrated speaker amp, that IMHO is one of the best ever made, a PASS LABS INT-150, which I feel is the best SS amp I have ever heard, and the only one rivaling any & all amps in clarity, realism and even soundstage(!)...

    So in comparison, the Oblivion held itself to be in same catagory of realism, clarity, soundstage, just less power on tap.

    The PASS amp was simply majestic in its rendering of effortless power and clarity. It either equaled or was above anything else I have ever heard when using it on the Susvara or HD800.

    The only Achilles heel of the PASS amp would be, is the issue of headphones.
    A speaker amp will typically work with mainly the Susvara, HE6 & HD800 straight out and best.
    Most all other headphones are too sensitive, and so you will hear noise floor with them on a speaker amp.

    Thats why for the price, I feel nothing can currently beat the Oblivion amp.
    Yes, at $3-4k level and up we have choices, but I still would choose it over all the other amps I mentioned so far (my own preference due to its imaging).
    Bottom line, its not easy to beat this amp. ..
    Last edited: Apr 19, 2019
    BreadMaster and nick n like this.
  15. Maxx134
    If your using the wo33 (in your profile picture) on a Susvera, I mentioned before it also had a bit more noticeable punch.

    So thought it was just more powerful, untill I EQ the Susvera on my Oblivion and heard same impact yet with volume turned up higher, so it is both a power and tube altering difference for the wa33.
    Regardless of price I would still pick the Oblivion sonic image.

    I am assuming the advantage/strong point the Oblivion has, is in its handling of transients and recovery.

    The topology is the advantage.
    All manufactures need to focus on the issue of transients and parasitics, in a similar manner as MrCurwen has shown.
    Last edited: Apr 20, 2019
    nick n likes this.
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