Oblivion | UltraSonic Studios
Dec 30, 2019 at 4:15 AM Post #271 of 7,457
If my headphones only have the standard 1/4" or 3.5mm plugs and I don't have balanced cables (T1 and HD650), how do you use the XLR jack?
Then you need to get a balanced 4-pin XLR cable for them.

In the Oblivion send to me, there is only xlr headphone out. Sonic could easily have included both 1/4 rca and xlr out for headphones. That way your headphone plugs of 1/4" or 3.5mm could be easily catered for. :)
I can do it but not that easily. It would complicate things somewhat as there would need to be a switch in between the the SE jack and the output transformer. Oblivion and Citadel have balanced outputs, meaning there're two phases in anti-phase to each other per channel with a centertap to ground. When using single ended output jacks, such as the 1/4 jack, one phase goes to ground.
I still don't recommend this as the balanced output is better.

There. That's what he says. He was referring to my Sansui that has balanced xlr input. If you have rca unbalanced input, then do similarly.
Not that easy. Again, the output are balanced so the amp you're feeding needs to have balanced inputs. I can build this pre-amp option either with balanced (XLR) or SE (RCA) outputs.

I think this is what you need to use the headphone out of Oblivion as preamp to your main amp. https://www.amazon.com.au/Duttek-6-...ocphy=9071740&hvtargid=pla-309645342180&psc=1

Sonic to confirm. To be safe and sure. :)
That would work if your amp has the 1/4 jack on the front. You can not use an adapter that goes from 4-pin XLR to 1/4 and then that cable above for example. Never use a balanced to SE adapter of any sort!
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Dec 30, 2019 at 2:47 PM Post #272 of 7,457
Back from the beach house. The traffic jam along the way is incredible. Sydney despite the bush fires is still incredibly good looking.

Wow, Sydney looks so amazing!

Edit: Why don't we all send postcards like this on the thread, it certainly cheers us up in the cold, and grey countries lol!
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Dec 31, 2019 at 7:41 AM Post #275 of 7,457
One other thing I discovered is that the spike feet are adjustable in height. When I first place it on the table, it was not level or the table's not level. So I place a 10 cent coin under the feet of the front right spike. Now that I know how to adjust the feet, the coin is taken out .... forever ! Good idea on the spike feet Sonic !

If you didn't want to do that you could always unscrew the feet and put a couple of washers on the thread then screw the feet back. I do that because I don't like the look of them unscrewed, also it can raise the height even more if you need to clear fans for maximum air flow.
Dec 31, 2019 at 8:04 AM Post #276 of 7,457
Helsinki has like 15 minutes of sunshine once every three days..

That bad... one positive is that you can stay inside and play music and build amps!

Balanced output is better, but I for one use only SE output in my amps. My AKG headphones have SE wires.

For anyone interested there is an interesting discussion on balanced vv SE in head-fi. I say discussion, more like a slanging match. I don't believe either is better, it boils down to the design, a quality SE will beat a so so balanced. I did not see anything that convinced me that a good balanced design was better than a good SE design. Various measurements were given that indicated to me that, at least at the present time, no objective evidence existed to prove that balanced was better, neither did balanced affect headphone drivers preferentially. Of course balanced does have advantages in noise cancellation, long distance use and such like.

Balanced definately sounded better in my LD, more defined sound, whether it is in theory I'm not so sure.

Share your cold with me. It’s greater than 40 degrees today.

Thank you, that's 20 degrees each, not bad for this time of the year. We touched slightly over 40 last year, a record for summer!
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Dec 31, 2019 at 8:58 AM Post #277 of 7,457
If you didn't want to do that you could always unscrew the feet and put a couple of washers on the thread then screw the feet back. I do that because I don't like the look of them unscrewed, also it can raise the height even more if you need to clear fans for maximum air flow.
I recommend the spikes to be unscrewed to give the fan some airflow.

Balanced output is better, but I for one use only SE output in my amps. My AKG headphones have SE wires.
Balanced definately sounded better in my LD, more defined sound, whether it is in theory I'm not so sure.
I'll just clarify this somewhat.
What MrCurwen means is that he built a balanced amp with SE output. Not an SE amp. That sounded a bit strange to me when he first told me some years ago now. But, the moral of the story is that the amp still operates in push pull (balanced), then the signals (the two phases) are summed in the OT primary. From there you can either choose to have a balanced output or an SE output.

The LD MK6 is a totally different topology and design which does not sound good with SE out.
Dec 31, 2019 at 11:22 AM Post #278 of 7,457
I recommend the spikes to be unscrewed to give the fan some airflow.

Yes they should do that.

I found with the LD I needed a bit more height for the fans so I put in longer thread screws with a few washers on top, then you can still unscrew the feet as well if you need even more height. Not needed on the Oblivion though.

Dec 31, 2019 at 5:13 PM Post #281 of 7,457
My review.





About 2 months ago I was approached by Sonic to review Oblivion. I had not known Sonic before neither did I hear about Oblivion.

I told him I’m not a professional reviewer and he said that’s ok. I’m not a technical person either so this is a layman’s review.

Oblivion is a hybrid amp with tube as preamp and solid state for the power amp duties. For more information on Oblivion, you can read it at the links above.

When I started, I view Oblivion only as a headphone amp but I soon found out that you can also have one configured as preamp and / or with speakers out.

After 2 months, I received the amp 2 days before Christmas. :) It came in a very big box. Inside, it is very well padded and has another box – Oblivion is in there, again very well padded. It came with 2 x RCA 6AV6 driver tubes and 4 x Siemens EL81 power tubes. The amp that was send to me has an impedance switch, another switch to enable headphones or speakers / headphones and speakers binding posts that accept banana plugs. It also has xlr and rca inputs. The headphone out is xlr. Power switch is of the flick variety and it is very sturdy and feels good to the touch. The volume knob operates smoothly.

Visually, Oblivion looks very good. It comes in a large brush aluminium black powder coated chassis. It is slightly bigger than my Yggdrasil dac. There are 4 adjustable spike feets which makes levelling the amp on the table very easy. There is a big fan underneath to keep the amp cool and it is very quiet. The amp stays just moderately warm even under hours of usage.

I will start with the review of Oblivion as a headphone amp. My gears are as follows:-

Yggdrasil – dac ; Oblivion – amp ; ZMF Verite and HD800 – headphones.

Cables are Curious cable interconnects, Isotek EV03 Premier power cable, a generic power conditioner similar to the Isotek EV03 Polaris power conditioner.

Now how does it sound?

Oblivion strikes me as very clear with details galore. Stereo imaging is superb. You can hear instruments clearly and visualise where they are positioned. Soundstage depth, width and height are the best I’ve heard in all the amps that I’ve experienced. Treble is very well extended. Midrange is forward and engaging. Bass is well done without overpowering the other frequencies. Whilst it’s lighter in bass than some of my tube amps, it surprised me on bass heavy tracks. I soon discovered that Oblivion will reveal how your gear sound and perform. It is very transparent. There is a touch of tube tone and at no time did it sounded glaring or bright. Spacious, airy and articulate comes to mind. With Yggdrasil and Verite Open, it sounded like a perfect pairing to my ears.

My other 3 tube amps are ALO Audio Studio Six, Glenn OTL amplifier and Woo Audio WA22 and the preference are in that order.

Compared to Studio Six.

Studio Six has Mullard ECC33, Brimar CV511 (equivalent of 6V6gt), Mullard OB2 and GEC U52.

Studio Six or SS has rather pronounced bass. It’s solid. It’s also very detailed with a sweet midrange and accentuated bass. It’s great with classic rock.

On switching over to Oblivion, it’s obvious that Oblivion clarity and details are more in abundance and soundstage is wider, deeper and has more height. Oblivion imaging is also better. It is certainly airier and projected a holographic image. Studio Six is the best of my 3 amps ( – in my opinion :)), so it came as a shocked that after a few days of comparison, I found myself preferring Oblivion tonally with my gear.

Compared to Glenn OTL amplifier.

I had GOTL for 2 years now and am very familiar with it’s tone. It’s a tube rollers amp but my preferred tubes are Sylvania 6sn7w metal base with 6 x RCA 6bx7gt. GOTL has an upfront engaging midrange and it’s midbass is superb with Verite. Treble is well extended but a bit dial back compared to the other amps. It’s an organic, dynamic and lively amp. Compared to Oblivion, GOTL sounded less clear. Very good texture but clarity and details are not up to Oblivion class leading act. GOTL soundstage is also much narrower. Despite all this, I actually like the way GOTL sounded with classic rock.

The areas Oblivion trump over GOTL is in clarity, details, imaging, airiness and soundstage. They are quite different sounding tonally.

Again I find myself preferring how Oblivion sounded compared to GOTL.

For this exercise, I decided to skip Woo Audio WA22.

GOTL was my amp of the year for 2018. Studio Six was my amp of the year for 2019. Oblivion will be my amp of the year for 2020.

With the impressions of headphone duties out of the way, let’s get to how Oblivion fair with speakers. My first thought is that Oblivion will be suitable only for high efficiency speakers like the Zu Omens or Omegas. Well I was so surprised that Oblivion drives the following bookshelf speakers so well.

Axis LS28 – 88db, 100w max power handling, 8 ohms

Wharfedale Diamond 10.1 – 86db, 20 – 100w power, 6 ohms

Furthermore I was astounded that Oblivion could drive my Axis LS88 floorstanders (90db, 300w power, 4 ohms) to moderately loud level. I have to admit though that I much prefer my Sansui au-alpha 907mr and Redgum Rgi120enr for driving my large speakers in a fairly large room of 6 x 4 metres. There’s just that much more oomph. I was using my Rega RP8 turntable with Avid Pellar phono stage for this test.

The bookshelf speakers sounded excellent with Oblivion driving them. For near field listening, there is certainly enough power to drive them. There is no need for high efficiency speakers. I have not heard those speakers sounding so clear and bass was amply delivered with good solid impact.

Music selections for the listening test.

Telegraph Road – Dire Straits

Forever Autumn – War of the Worlds

1812 Overture – Tchaikovsky

Ride of the Valkyries – Richard Wagner

Comfortably Numb – Pink Floyd

Nothing Else Matters - Metallica

Spanish Harlem – Rebecca Pidgeon

Stairways to heaven – Led Zeppelin

101 Eastbound – Fourplay


Oblivion performed superbly as both a headphone and speakers amp. I would be proud to own one.

If you value transparency and an articulate sound, you will love it.

@SonicTrance has created an amp that not only looks beautiful but also sounds great.

My prediction is that it will take off as more people come to know of it. Highly recommended !
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Dec 31, 2019 at 6:00 PM Post #284 of 7,457
I more than like it. I adored it now. :)

One aspect I didn't mentioned is how quiet it is with no music playing. Those tubes and amp produced no unwanted noise or hum.

Another aspect is the fast transient speed. I love amps that are agile and not sluggish. Oblivion is the best of the lot I've heard. However what surprised me is that there is still a very nice tube tone. You have the best of both worlds here.
Dec 31, 2019 at 6:38 PM Post #285 of 7,457
It’s too bad their isn’t a Electrostatic Oblivion amp. :wink:

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