UltraSonic Studios Oblivion Review

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by purr1n, Feb 6, 2020.

  1. purr1n

    purr1n Finding his inner redneck

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    I don't usually do unboxing photos or gear porn shot, but I think this one deserves it - given that it's coming from thousands of miles away, I think Asgard or something like that. The USPS as usual waited 5 seconds before deciding no one was at home. I sent my wife to pick it up at the post office, and she said the box was big - not heavy, but big. LOL, I didn't expect this big! Good thing she had the Jeep with her, otherwise it would have been a wasted trip. BTW, the post office took half an hour to find it. Good thing they didn't lose it. I guess they expect the box to be so big either and were looking for a smaller box.

    IMG_20200206_081325.jpg

    Turned out it was double boxed. This is a good thing for international shipping. Hopefully nothing came loose during shipping. It's not uncommon for screws to come loose or solder joints to drop with international shipping. If you've ever seen cargo handlers outside of planes throwing boxes, even ones as large as this on the conveyor belt, only for the box to fall off the ramp and into the tarmac, then you will understand.

    IMG_20200206_081502.jpg

    Here is the amp taken out of the box. The amp is suspended by its left and right side with large foam blocks. The chassis metal is certainly thick strong enough to not deform. The darn thing almost feels like a solid block. This feels like it would be an amp appropriate for the commanding officer's cabin on an armored battleship in WWII. (I didn't quite get that sense in prior photos I've seen of this amp, so I figured I would say something about it).

    IMG_20200206_082337.jpg

    I ordered the optional speaker taps (this amp doesn't have much power, but it will do 4-ohms - might do well with my speakers). Note the nice spiked feet. This is looking like a better and better deal given how expensive stuff costs up there - assuming the sonics pan out (and I have no reason to suspect that they will not given hints to the amps topology). Hopefully UltraSonic Studios will hold off from drastic price increases a la Feliks if and the brand gets more recognition. There is a large fan underneath the amp which is suspended to the bottom plate with rubber mounts like PC fans. I'm not totally sure if this is necessary, but it was probably put there out of an overabundance of caution.

    IMG_20200206_082716.jpg

    The current meters are not necessary, but nevertheless are a nice touch. Take a look at how thick the front plate is! As I said, this thing belongs on a battleship.

    IMG_20200206_083735.jpg

    Here a shot of the front panel. Utmost simplicity. Power switch and LED. Output selector and a large weighty volume knob.

    IMG_20200206_083313.jpg

    I'll do an inspection all around, maybe drop the bottom plate to make sure everything stayed intact during shipping. And then attach the tubes and fire it up. Stay tuned for impressions.
     
    Last edited: Feb 7, 2020
  2. Walderstorn

    Walderstorn Friend

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    I love the looks of it. I am specially a sucker for current meters or similar dials, always enjoy having that look.
     
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  3. supertransformingdhruv

    supertransformingdhruv Almost "Made"

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    I didn't realize it had that big-ass fan on the bottom-- it doesn't appear in any of the glamour shots on their website. I'm very curious how hot this guy gets, especially driving your 4 ohm speakers, and how audible that fan is.
     
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  4. SonicTrance

    SonicTrance MOT: Ultrasonic Studios

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    Purr1ns Oblivion was the last amp that ships with a fan. Unless someone wants a higher powered speaker amp. The fan is very quiet but not necessary. Just keep the amp well ventilated and you'll be fine.
     
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  5. Phantaminum

    Phantaminum Friend

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    The amp doesn’t get hot at all when operating but the fan does give you peace of mind.

    Imagine me, going to the post office to pick this beast up in my Honda Civic. I had to do an “unboxing” of the amp in the middle of the parking lot to be able to get it in the trunk.

    You can’t ever say that he doesn’t pack his amps well.
     
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  6. cskippy

    cskippy Creamy warmpoo

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    I’ll take a fan if it means more power! ;)
     
  7. mitochondrium

    mitochondrium Friend

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  8. mscott58

    mscott58 Friend

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  9. purr1n

    purr1n Finding his inner redneck

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    First impressions (subject to change):

    IMG_20200206_181420.jpg

    I was disappointed at first because the clouds did not part, nor did I hear the sound of angels. But after I came down to earth, I would have to say that the Oblivion gets the nod. No, it's no giant killer, but the price is appropriate. And when I say that the price is appropriate, it's to SBAF's much tougher standards.

    I've left the amp turned on for at least an hour now since I have no idea how long the tubes have been stored away and left unused. The tubes provided were Sylvania EL81 for the drivers and 6AT6 type (Siemens CV2121) on the outputs.

    IMG_20200206_194803.jpg
    IMG_20200206_194745.jpg
    Unsurprisingly, the amp reminds me a lot of the ECP T3, particularly one owned and tweaked by @drfindley back in the day. All T3s will sound different because the builds are different.

    It would be interesting to compare against the DNA Starlett, but really, just different beasts and different topologies. My sense is that the Starlett has better microdynamics and microdetail and more expansive stage, as should be as it is more expensive. As I said before, the price is right and places exactly where it should be. Maybe should even be priced higher given the solidity of the built.

    I believe that @Phantaminum may have mentioned a few things in terms of where is stands in relation to the DSHA 3F (a bit behind) and I would be in agreement. The Oblivion doesn't have quite that transparency.

    Plankton and microdynamics seem about on par with T3, but sense of drive is greater. The staging is similar, not particular deep nor expansive, but width with precise imaging, although it does suffer from hole in the middle effect. The presentation is snappier than most other amps, but not in a bad way. There some sharpness of transients with the Verite (universe pads), which I don't usually hear with other tube amps. I do feel the T3 bass articulation was better, at least when the T3 was equipped with the better optional Cinemag OPTs. Bass quality isn't bad, but I don't it's the clearest and it doesn't quite keep up with the highs. It would be interesting to see if distortion measurements correlate.

    Keep in mind I'm being nitpicky.

    I'll reterminate some other headphones to XLR and report back.

    @SonicTrance: can I ground / common the secondaries at the output? I have speaker binding post to stereo phono jack adapter. We be easier for me to use this instead of pulling out the soldering iron to reterminate headphones.
     
    Last edited: Feb 6, 2020
  10. SonicTrance

    SonicTrance MOT: Ultrasonic Studios

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    The Siemens EL81's (CV2721) are the output tubes and Sylvania 6AV6 are the inputs. There's no 6AT6 in your amp. Just so there's no confusion. If you put a 6AT6 in your amp it'll run very hot as the input stage uses fixed grid bias. Only 6AV6 is compatible.

    When I do the 48h burn-in I always use the tubes that ships with the amp. They're a part of the burn-in process.

    The speaker outputs are also balanced. Both black and red terminals are carrying signal in anti-phase to each other with a centertap to ground. To make the output SE, like you want, you need to ground one phase per channel internally to the main bus bar. Not sure how your adapter is wired (probably just ties the "negative" terminals together) but it can't have any connection to the signal ground. I never recommend using a balanced to SE adapter of any kind. I realize your adapter is not actually a balanced to SE adapter since most speaker outputs are not balanced like they're in Oblivion.

    So, no, don't use that adapter. Better get that soldering iron out!
     
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  11. Phantaminum

    Phantaminum Friend

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    Thanks for the review @purr1n. One thing I did want to mention (from the pics) is that I personally did not like the Verite with the Oblivion. The pairing sounded “OK” and has better synergy with other tube amps. Even rolling different pads didn’t alleviate this. Now, paired up with the Auteur or Verum One it made a much bigger impact on me.

    If you’d like, I could send either (or both) headphones to broaden the pool and perspective. I feel those headphones show off more what the amp is capable of.
     
    Last edited: Feb 7, 2020
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  12. Taverius

    Taverius Smells like sausages

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    Oh neat, a reasonably priced amp in the gaping void between your Lyrs and whatnots and the 3k+ big boy amps! And no need to pay import tax for us eurofolken!
     
  13. songmic

    songmic Gear cycler East Asia edition

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    There is already a dedicated review thread for UltraSonic Oblivion. I know @Maxx134 and his review style isn't exactly liked by everyone here, but does that warrant creating a new thread? Think about how often we have rebuked Randos for starting a new thread on something that already has a pre-existing thread.
     
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  14. purr1n

    purr1n Finding his inner redneck

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    ^ This.
    • Rests in what is typically no-man's land. Fills a gap.
    • For once, something that sounds good for not too much money, and is more of a bargain for people in EU.
     
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  15. Roget

    Roget Rando

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    I am immune to hate so I will say.

    Maxx's review does not reserve recognition. I do not trust subjective much. I maybe trust a little from purrin who used controlled blind and volume matched tests in the past. I expect purrin or bob to provide measurements.

    Future project could be counting many impressions and scoring. This is like medical studies of medicine.
     
  16. purr1n

    purr1n Finding his inner redneck

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    1. This will make the front page featured articles. Do we really Maxx's review on front cover of the book? Do we want people thinking we've become HF.
    2. Rules, protocols, customs, can be broken, especially when the benefits outweigh the benefits. Double-standards may not apply here.
    3. There have always been double-standards. More meritorious members get to break rules (on occasion) and post more garbage.

    That would be an interesting idea for gear where we have a large number of impressions. Measurement extremists love to point out how subjective impressions uncontrolled cannot be trusted. However, what if data from set of uncontrolled subjective impressions shows many people arriving at similar specific conclusions? Not too terribly different from pain medication studies where a person's pain cannot be measured.
     
    Last edited: Feb 7, 2020
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  17. purr1n

    purr1n Finding his inner redneck

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    I figured before I reterminate my other headphones, I'd take some measurements of Oblivion.

    These are 1kHz and 35Hz steady state sine waves at 0dBu (0.775Vrms), enough to hit 100-110db on most headphones. The load is 330-ohms. I combined both 35Hz and 1kHz measurements (taken separately) together to better distinguish AC mains (multiples of AC at 60Hz) from the harmonic distortions of the 35Hz signal.
    upload_2020-2-7_18-45-40.png
    Note second harmonics are -63db and -59db for 35Hz and 1kHz respectively. Third harmonics are -53db and -76db for 35Hz and 1kHz respectively.

    Repeating below for -10dBu sine waves. Same 330-ohm load.
    upload_2020-2-7_18-52-20.png

    Finally for -20dBu
    upload_2020-2-7_18-54-7.png
    Note at lower levels, the 2nd harmonic is less than the 3rd for the 1kHz signal.
     
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  18. purr1n

    purr1n Finding his inner redneck

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    Gain is about 13.22 (using 0dBu output from AverLan in inputs and volume pot maxxed)
    upload_2020-2-7_18-58-56.png
     
    Last edited: Feb 9, 2020
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  19. purr1n

    purr1n Finding his inner redneck

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    Oblivion THDN vs Frequency 0dBU at output for 30-ohm and 330-ohm loads.
    upload_2020-2-7_19-7-46.png
    Note slightly higher distortion for 30-ohm load from upper bass to mids. Both loads indicate rising distortion toward the bass. This is typical for tube amps with output transformers running at higher output levels. Note that the ECP is quite a bit better in this regards: https://www.superbestaudiofriends.o...o-t4-technical-measurements.8923/#post-289058

    I suspected this might be the case as I stated in the my subjective impressions that nitpicked how the lows lacked ultimate clarity and were slightly veiled or murky. These levels are likely to be audible. There could be something to @Phantaminum statement that the Verite were merely an OK match. This makes sense as the Verite is a bass boosted headphone.

    This is -10dBu at the output (red) compared to the 0dbU (green) into 330-ohms. Overall lower THD+N, but similar pattern in the bass with increasing distortion/noise.
    upload_2020-2-7_19-20-12.png
     
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  20. purr1n

    purr1n Finding his inner redneck

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    The Signal to Noise Ratio (SNR) test measures the difference between a signal being output from a device under test vs. the noise floor of the device with no signal.

    SNR vs input (to arrive at output, add +13.22 gain). Typically we'd be using most headphones around the -25 to -15dBu range below.
    upload_2020-2-7_19-33-49.png
     
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