Burson Audio - Soloist SL - Headphone Amplifier

General Information

The Soloist SL is a concentrated version of the award winning Soloist. Its DNA is identical to the Soloist and it exists for one purpose only. That is to be one of the best headphone amplifiers in the world. Just like the Soloist, the Soloist SL is completely discrete in design. (IC free). It features the same 21 component Field Effect Transistor input stage and the same discrete power supply network which brought popularity to the original. Assembled with the same high end components and operating in pure Class-A, the Soloist SL carries the same sonic signature which has been described as the utmost in organic and transparent. At 14cm * 8cm * 21cm (5.5" x 3.15" x 8.26") it sits elegantly on any desktop. But with 2 Watts per channel into 16ohm, the Soloist SL is one of the most powerful headphone amps in the world. It is capable of driving most if not all headphones to their full potential. Coupled with a 2 level gain switch, it offers infinite flexibility. The Soloist SL is housed in a refined and precision folded 3 mm aluminium casing that is unmistakably Burson. This case also works as a singular heat-sink for the entire machine ensuring stable and optimized performance at all times. This case really puts the conventional 1 mm folded steel case and generic heat fins to shame. The Soloist SL features a new Variable Output Stage (VOS). It enables the Soloist SL to match well with any type of headphone. Be it easy to drive high sensitivity in ear monitors or open back moving-coil designs. It can drive anything including the latest planar magnetic headphones with ease. Combining the VOS with high quality ALPS Potentiometer, volume control is always smooth and synergy is always perfect. An athlete needs clean air to perform at an optimum standard - audio equipment needs clean power to reproduce transparent and natural music.

Latest reviews

Pros: Value, sound quality, power, versatility
Cons: Not the end all in terms of power
From my R2R-11 review, "I'll be very honest. One of my favorite sub-hobbies in the grand scheme of head-fi is auditioning and discovering giant-killing gear. To me it's pretty fun putting much less expensive gear up against bigger, fancier kits to see how well the David compares to the Goliath."

I'm quoting the above because the Soloist MkII from Burson is another piece of giant-killing gear. It's a diminutive solid state amplifier that offers the sound quality, build quality, and smart design that in a lot of places, costs much more money!

Instead of the normal breakdown - bass, mids, treble, soundstage, etc - I'm going to go through this review according to the pros and cons list above.

For the MSRP of $499, the MkII version of the Burson Soloist is a no-brainer if you're in the market for a solid state amplifier, especially if your primary headphones employ dynamic drivers. I've owned/auditioned several SS desktop amps from the likes of Schiit, Audio-gd, and Cavalli to name a few, and if you're in the market for something that does just about everything well, but can't drop more than $500, I heartily recommend this guy before anything else.

Sound Quality:
In a word, enjoyable. Compared to the RNHP from Rupert Neve (which ain't no slouch!) the Burson throws a more realistic soundstage, offers more texture on the low end, and contributes a bit more air in the upper regions.The Neve might be said to offer a more studio-quality sound while the Soloist pursues a audiophile-quality. I'm a Grado-head to be sure (let the ice-pick, shrill, science project comments fly!) and my go-to headphone is the original PS1000. While just about every other Grado is served best from an all tube design (MAD Ear, Kenzie, WA6), the PS sounds best out of something valve-less. Enter the Burson. It takes the PS deep, stays true to the Grado midrange, and very cleanly and enjoyably portrays a treble range that is neither abrasive nor shrill.

'Comfortable' power:
Here's what I mean by that: Everything I've thrown at it has been driven very well, and what I mean by that is not necessarily that there are gobs of power on tap (I've learned that gobs of power is not always better if it means I only have 10 degrees of play in the volume knob), but rather the drivers are firmly controlled and clean. No weird soundstage or low bass issue, both of which can be affected by insufficient powering. The most difficult to drive headphone that I've used is my pair of Paradox Slants and on hi-gain, these are plenty loud at 1:00. It bears mentioning also that music comes from a very black background. Better than the Schiit Lyr and RNHP for my Grados for sure. Not sure about IEMs because I don't use mine at my desk!

In addition to the aforementioned driving power, the Soloist offers two RCA inputs as well as a high/low gain button. I'll mention here that I appreciate the straightforward approach in this area. While sometimes things like crossfeed switches, additional gain levels, and other options are nice to play with, I generally like to 'set it and forget it.' The MkII lets me do that!

Not really any that I can think of. I suppose that if you're strickly a planar guy, this might not have quite the power that you might want, but that's really a quibble at this point.

So in conclusion... the MkII version of the already acclaimed Soloist from Burson is a great choice for a desktop SS amplifier for the budget-conscious listener. You could certainly spend a lot more money and do a lot worse in this hobby. I bought it on a whim and it's not going anywhere anytime soon!
The real bang-for-buck is the Magni 3. It destroys the original standard for amp pricing and sets its new one for all to follow.
Magni 3 won't put you in the audience. This one would, with right dac and hps.
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Pros: transparent refined sound, flexible gain stage lets you use from iems to planars
This is review of mk 2 version of this amp. I bought it from directly from Burson Australia. 
Ordering Experience:
Ordering experience was great from Burson. They had a clearance sale going on at that time where it was listed for $400 which is still going now. Product listing showed mk 1 but they sent me mk 2. Extra points for making me happy. I asked them what was shipping cost and they said shipping was included. I thought maybe they will use some cheap shipping method but nope. It was simply best import experience I ever had. They used fedex and amp reached me in a week total. From Australia to India including customs halt which can normally take a month, thanks to superior service by fedex. My guess is it costs Burson around $100 to ship it but they don't make a big deal out of it in their marketing. Understated and classy. I like that. This makes it close to $300 for amp alone, thats close to ifi ican or schiit asgard. You can now probably understand why I called it best value in headfi right now.
Build and packaging:
Amp is shipped in card bord box with generous foam cutouts to keep amp safe. It includes power cable and rca chords of good enough quality. You can use fancy cables if you like. Power chord is iec type, ones that are used in computers. It has on board power supply and does not use power brick. Build quality is stellar and high quality. Its made out of brushed aluminium thats smooth to touch. Not too big or heavy and you can transport it easily from one room to another or safely in its box if you plan to take it to a meet. It looks great in pictures and in real life its as good as marketing shots we see on burson site. (something I cant say about all products, ahem schiit modi/magni) It comes with 2 inputs on back and 2 gain stages switchable by relays. This makes it feel more upmarket than say dip switches. Burson branding is engraved on front face plate and looks cool. Overall stying of amp is understated and classy. One thing I liked better on mk 1 of this amp is chunky volume knob. On mk 2 they have made it a little small. It works well and rotates smooth though. Allows you to make fine adjustments easily even if you listen to iems. ( something I cannot say about portable amps with hard to rotate volume knobs and aggressive gain stages like my fiio E12.)
Sound Quality:
SQ wise I consider it worthy of using with high end hps like Sennheiser HD700, say in $800-1000 range. Its an upgrade over entry level solid state amps like ifi ican or O2. When using AKG K550 and Sennheiser HD700 on something like ifi ican, I can't justify spending more on HD700. But on burson, HD700 pulls ahead enough so that it becomes a clear upgrade. By upgrade I mean more fleshed out instruments, more meat around bones. Clearly you get closer to live performance. 
On bringing something like Sennheiser HD800 in mix, I feel benefits of using higher end hps diminish slightly. HD800 offer superior resolution but not enough to be a huge upgrade. So if TOTL cans are on your shopping list I suggest you look into its elder sibling Soloist, perhaps. For high end hps (under TOTL hps) this is a perfect match and imo you are not spending disproportionately on your rig either on hps or amps.
Or if you have a set of mid fi cans like AKG k550 or philips fidelio X2 that you love and want an amp that brings out all that hp has to offer, this is a good bet.  
Tonal Balance:
Its transparent as far as I can tell. Presentation is on lighter side. Bass is strong and punchy. Mids are resolved and clear. Highs on hps like HD700/800 are well controlled and not at all harsh. Maybe even brighter cans it will be troublesome but with a well balanced hp like HD 700 (it has some warmth) its a stellar pairing. I also loved it with audeze lcd 3. Excellent drive and bass. Creamy mids and gobs of detail without getting harsh. On ethereal cans like AKG k550 or Beyerdynamic iDX200IE, sound is not harsh but ligher character of hp can make it too crystalline. I prefer to use warmer source when using K550 with it.
Overall its transparent enough to allow full character of hp to come out. HD700 sounds even warmer, AKG K550 sounds crystal clear, Sony XBA A1 sounds warm but still clear. Whatever is tuning on your hp it will come out like that.
Special note on IEM usage: if you thought iems have no soundstage and too in-your-head feel, try listening to them on burson soloist sl. It makes my $100 Sony XBA A1 sing. Being hybrid iems they dont have great soundstage so I thought. On burson it sounds like full sized hps. Sound comes from in front of you even when IEMs are tucked in your ears. This has increased my respect for IEMs and its those tiny amps that are at fault and not IEMs.
Soundstage wise its well layered from front to back. Hps with great soundstage like HD700 will benefit immensely from it. Has more depth than width and pin point front to back layering. Bass has its own layer and brings out multiple bass layers out very well if your hp is capable of it.
Value and conclusion:   
As I have already said, its exceptional value considering its $400 shipped. And shipping method is best I can have as well. Its performs on high level and together with HD700 is hard to put down combo. My no of hours I listen to music increased after I got burson cause its so hard to put down.
Special note:
I am including this note on request of Shetzu as he does'nt writes reviews.
I took it to my friends place Mr Aniel goes by handle Shetzu on headfi who used chord mojo to drive his HD800. He instantly ordered one after hearing it and its price to be used as mojo-burson-HD800 rig. That rig is best I have heard. Very transparent, amazing detail on vocals, completely alive image with great microdynamics and detail. To him biggest difference was soundstage that only proper big desktop amps can offer.
Pros: Small, Good amount of power, Great build quality, Natural tone
Cons: a bit dull sounding, Can't drive planar dynamic headphones to full potential, Noise floor heard on high gain around 2-3 o'clock
I don't want to ramble too much in this review, but I want to give a slightly counter perspective to the majority of reviews for the soloist sl. I used it with a schiit bifrost uber using the usb input, and with my audeze lcd 2 headphones as well as my denon d5000 headphones.
So the first couple days of use the sound was great, basically sounded just like most of the good reviews it has gotten. If you want to know what that sound is like then just read those other reviews because I want to speak about what happened after a couple days. Starting on the third day of use (and by third day I really do mean like 24+ hours of total use by that point) the sound started to lose a little edge, and little liveliness, a little grip. I gave it a few more days, tried every usb port, tried the optical port, switched headphones, used different songs/media players, but the sound remained consistent. It was subtle at first, but it just felt like your brain was having a hard time trying to latch onto the music, if that makes sense? the edge was gone, it always felt like something was missing in the sound, as if it was blurred over slightly or dulled. The bass was still great, the mids were still great, and the treble was still properly detailed, but as a whole the tone seemed to just dull the edges too much, which made the sound feel much less dynamic than it should, and after a while it just hurt my brain because it was being teased with details that just would not appear. The final straw for me to sell it though was the fact that it just did not provide enough power for the lcd 2 (the late 2013 pre-fazor version). Even on high gain I had to put the volume around 2 o'clock to hear the whole frequency range properly, but it always ended up being too loud after a while, but sounding as if it was too quiet. Like it would be too loud for your ears, but you kept making it louder because it seemed like it was missing aspects of the sound. Like the bass was good, but it obviously felt like it needed more power behind it, and the mids were great, that never seemed wrong, and the treble just sounded dull and lacked some detail. It just felt like if there was a bit more power, then I could keep the volume lower while having the sound be properly filled out. Compared to the soloist sl where it definitely felt like it was struggling to get the lcd 2 sounding right. With my denon's it had the proper amount of power, since they are very sensitive headphones, but that dulled sound made the denons pretty bad in the mids. See the denon d5000 already has a slight v curve frequency response, but the burson just made that v-curve even more v shaped. bass was stronger and tighter, treble was brighter, but the mids were too recessed. The lcd 2 sounded a bit better simply because it has a much more linear frequency response to this slight mid recession doesn't impact them nearly as much, but the dulled sound definitely does. On top of all this, the neutral/natural tone of the soloist sl just makes the dulled sound even worse because now it was lacking solidity and fullness, just brighter and dulled. it's a strange combination, but that's its sound signature no matter what you plug them into, or plug into them. Some people like that sound signature, their ears just enjoy that kind of thing, but for me I just really did not like it at all. I am looking at the violectric amps as my choice instead. Also to give some proper information about the soloist sl out there about its power output, it puts out about 650mW into 50 ohms. The 2 watt rating they advertise so much is only at 16 ohms, even my denons which are at 25 ohms only get close to a watt if using high gain, which is a lot for them, but 650 mW for the lcd 2 is only just barely enough to make them listenable and sound good, but very quickly you will feel like it just isn't enough.
So I will advise to definitely listen to a burson product first before you buy, this is not a company that makes products that you can safely buy blindly and enjoy. On youtube there is a guy whose channel name is headphoneaddictdotcom and he also agrees with me on this burson sound signature annoyance when he used a burson conductor for a few months. He also preferred violectric amps or just something more along those lines of sound signature. I have similar tastes to him, as in we like the audeze house sound, pre-fazors, denon dxxxx line, fuller and thicker sounding amps, neutral dacs, etc. If you feel you have a similar taste preference to this, then you might not enjoy the burson products in general. I just don't see that many negative reviews for their stuff, and thats why I originally bought the sl, and was very disappointed as I mentioned above, and just wanted to make sure people have all sides available to them before buying.
Nice review, sax. I have the orig Soloist, and it's excellent with my LCD2.2 I guess Burson compromised too much when they slimmed to the SL. btw, I never play computer files thru Soloist. Only a damn good source, like a CDP or Brsyton's BDP-1BDA-1 will do -- for me! Cheers.
Did you communicate with Burson about this?  Maybe a defective unit?  Interesting review and it's refreshing to read some criticism.  I agree that the soloist is not nearly enough for many planars, I tried the conductor and liked it a lot but -to my ears- it was just a bit too forward/analytical.  As you know I use the Vio V200 and it's overall better for me but not quite what I'm looking for either.  My F5 is fabulous but that's basically a speaker amp.
I dont think there is anything defective with it at all, it performed exactly the way it was supposed to perform. Unless there is some kind of weird defect that causes minor changes in the sound signature? I highly doubt that though. I just think it was not for my ears/my set up. After looking through some of the older threads/random posts about Burson products I can see theres a minority of people who feel the same way as me in terms of hearing a slightly lifeless and dull sound (subtle but there). It is a minority though, so that's maybe something to take into account. Like off the top of my head one specific mention of this is a headfonia review of the lake people g109 and in it it was compared to similar priced amps, the SL being the main one, and there is a sentence that straight up says the reviewer felt the soloist sl sounded lifeless and dull with the lcd 2 (pretty much a quote). I found that after I made my findings. And theres also just some random posts hidden in a bunch of different threads that elude to a similar outcome, mainly with audeze headphones. I noticed that was the main thing in all the posts. And like I said in the review if you go to youtube and find headphoneaddictdotcom, him and i had a lengthy chat agreeing on these findings and our similar taste preferences. We're just the minority lol.


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