Graham Slee Solo Ultra Linear Review by mark2410
May 6, 2015 at 12:08 PM Thread Starter Post #1 of 56
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Graham Slee Solo Ultra Linear Review
 
Thanks to Graham Slee for the loan.
 

 
 
First Impressions:  So out of the box it came and it’s a light little thing, or maybe it’s just light beside the power supply?  I have the upgraded PSU1 power supply and it’s a really heavy solid block.  God whatever’s in it, I feel like you could build houses with the thing.  So the amp, it looks kinda nice.  Now I haven’t pre planned how I’m going to actually hook the thing up, I’m realising I probably should but too late now.  Right, ghetto solution it is.  Hp out of the E9 and to the AV inputs on the back of the amp.  A classy looking solution this is not but hey it’ll do till I can face spaghetti junction.
 
It seems sensible to pull out the HD600’s has they are quite easily the best big cans I have.   First thoughts on listening, please bare in mind I haven’t used the 600 in a while so I do forget just how excellent they are sometimes.  I don’t know if it’s maybe just the tracks but things feel deeper and more holographic.  Highs seems super refined, highly easy on the ear yet just so choc full of detail.  It’s all completely uncritical non comparative listening so I know it means little but…… everything feels unquantifiably better.  Not brighter nor deeper lows nor more forward mids but I keep coming back to wanting to describe them as holographic.  These just feels something better and as I haven’t been able to quite swap back to just the E9 and actually do some proper critical listening I just cannot for the life of me put my finger on it.  Something effortless feeling somewhere.
 

 
 
Lows:  While I get the impression that the HD600’s are being better driven in the lows which when you get deep can cause issues for amps, there is something effortless.  As the only proper desktop amp I have, the E9 which I still think is super bargain levels of value, the Solo, well the Solo doesn’t even notice it.  In the way that a great battleship might sail unfettered right though a harbour of toy boats.  Playing with the Oppo PM-3’s and flicking back and forth it’s blisteringly apparent that the bass feels so much weaker on the E9, it just lacks the vigour and authoritative reach that the Solo gives it.   It’s not per say larger in the bass it just feels better are more articulated.  The E9 is struggling.  Honestly it’s most annoying for until the Solo I was very happy with the power the E9 was capable of delivering and new I’m thinking I’m forever going to be aware of what it lacks now.  
 
Quantitatively, the Solo actually feels perhaps a tiny fraction less bassy than the E9.   Less so that the bass is diminished but that it’s more cleanly delivered and therefore there is that hint less in the way of bass bloom.  The Solo isn’t particularly forgiving when it comes to low end articulation so you may want to try and feed it better quality stuff than some of the bass as is found on Miss Gaga’s tracks.
 

 
 
Mids:  It’s the same story as was with the bass.  The Solo feels like it is casually spiting it out at you and that its capable of doing vastly more should you ask it to.  The E9 feels like it’s already giving you it’s all.  They are just not in the same class.  It also becomes more notable that the separation between what a grown up amp, hooked up to the mains can do that a portable one running off a battery cant.  Flowing, and effortlessly detailed.   It’s just all so openly expressive, Regina Spektors “Ballad Of A Politician” with its eclectic cacophony of sounds feels so wonderfully layered an ensemble.  Everything is so singularity clear and distinctive you can mentally tear it from its place in the song and examine it to your heart’s content.  The imaging vocally is kick ass good.    The only real issue is if you feed it crap, you see info that you might happily wish it would more melt into the whole.
 
Tonally and quantitatively it’s a little bit middy and a little bit open.  The smoothest high quality vocals are too expressively rendered to truly give you that creamy, melty, Galaxy advert type sumptuousness.  There isn’t the thickness that works so well with creamy vocals.
 

 
 
Highs:  Much refinement, much detail, much nuance.  To be honest you wouldn’t have expected otherwise would you?  The difference is the more noticeable in big cans but it’s still noticeable with IEM’s too.  Things that are very easy to drive still manage to benefit from, well from what exactly I don’t know.   Maybe it’s the extra headroom in available power?  Maybe it’s a slight inclination towards an open and detailed sound signature?  It’s not what I would ever call “bright” you know, things like the Icon mobile or the FireyeDA they are bright, they have that noticeable lift and dazzle in the upper end.  The Solo doesn’t really do that, it’s just a little more explicit all over.    Actually when you really, really start to look closely at the treble it’s pretty mild.  The initial metallic impact of a cymbal is ever so fractionally dampened.  The immediate rattle and decay are both effortlessly perfect.  Just exactly how I would want them to be but I know that being ever treble sensitive, there will be those that love the raw brutality of impact.
 
It’s curious in that its edge it a hint calmed yet its exceedingly high level of clarity otherwise makes the treble more noticeably distinct and clear.  So when you get elevated levels of clarity giving the impression of brightness you aren’t really, you are just getting more explicitly distinct treble.
 

 
 
Connectivity:  It’s a pretty clean and simple affair.  You get two pairs of phono connectors on the back, input 1 and input 2.  While in normal usage I dunno what I’d do with the second input but for reviewing?  Oh god trust me, it made my life soooooooooooo much easier.
 
Interface:  Super simple.  6.25mm headphone socket on the front.  Volume dial. Then lastly we have the input switch, it can be for input 1, input 2 or in the middle which makes no sound come out.  Effectively it acts as a mute button.
 
Power:  Gobs of it.  Not only did it continuously feel like it was never in the slightest straining or that it didn’t have endless reserves, it could go loud.  I never got the dial past 12 o’clock and that was with the HD600’s and with a fairly quiet recording.  It always felt like there was tons and tons of headroom left it you need or wanted it.
 

 
 
Dynamics:  Dynamics tends to be more headphone dependant but with the power availability it never did that, hint of volume decline when a song explodes out from silence.  There was plenty of dynamic range to call upon at any instant.  It was perfectly happy to trundle along, meek and mild then rip your ears off.  Great for music but it did occur to me how much I don’t love that in movies.  Not that you buy the Solo for film watching but its dynamics I think could irk me after a while.
 
Transparency:  Exceedingly transparent.  Very open and detailed.  It does it too without being particularly breathy so you do retain much liquidity.  I suspect that’s where its “valvey” purported nature comes from.  Still, oodles and oodles of detail and transparency.
 
Build:  It’s a block of aluminium.  It has a hint of DIY esq charm as you can see clearly how the external casing is put together.  A bit of handmade craft like appeal about the thing.  It feels solid, sturdy and that if you dropped it it’ll chip your floor rather than explode on impact.
 

 
 
Value:  Hmm.  I’m not an idiot so I fully realise that we are in the realm of diminishing returns.  I realise that if I had the Solo SRGII here which is the near twin of the Solo Ultra Linear Diamond Edition that I have here, it’s circa £400 for the standard verses the £670 for this version.  Even comparing to the FiiO E7/E9 combo it would be silly to say that any high end audio equipment is “good value” but more do you get something of worth for your money.  The answer there is a clear yes.  The Solo Ultra Linear came in and quite effortlessly battered the snot out of every amp I have.  Sure it’s the most expensive so it should too.  It just opened up a new layer of performance from pretty much every single thing I plugged into it.  Even the itty bitty Trinity Hyperions I’ve been playing with lately.  I’m not saying that if I had £700 to play with I’d put £30 to the Hyperions and £670 to the Solo Ultra but if you’ve already got some first rate stuff, yes you will see an improvement over any mainstream output.  It’s not about getting great “value” it’s about eking all that you can, making your headphones be the best that they can be.
 

 
 
Conclusion:  Within a couple of days of getting the Solo Ultra in I came to a stark realisation.  That one it was very good but secondly that part of me wishes I’d never heard it.  You see as a rule I’m an IEM guy, that’s what I use most and they don’t really need oodles of power.  They also are for use on the go, not so much as being wedded to a desk.  Therefore I was happy with how everything performed and I had my E7/E9 combo for throwing a bit more power in when I wanted to.  In my head I knew it wasn’t the greatest desktop amp in the world but I was happy with it.  Now I’m not.
 
Spending hour after hour messing about with cables and headphones and IEM’s and amps and the variety of combinations you can make, the Solo Ultra just lifts everything it was hooked up to.  Sure it couldn’t make a £30 IEM challenge a £200 one being played out of a meh source.  It’s not a magic wand.  It did however immediately offer a new layer, not only in quality and detail but it improved the acoustic layering.  I feel almost a little spoiled in what it can do to things and then to go back to my old set up feels as though something has been stolen.  That hint of life, of vibrancy, of dynamics, of nuance has just ever so slightly been taken away.  Everything feels diminished and it makes me sad. 
 
The Solo Ultra Linear therefore stands quite easily head and shoulders above everything as the best amp I’ve ever encountered.  It’s that simple.  It is wonderful.  The however is that it’s of course not the cheapest amp I’ve ever encountered.  To most people out there it would simply be wild overkill to spend so much on an amp.  The fact is you pretty much always get a far bigger improvement in audio quality by putting it into a more expensive headphone than into an amp.  So if you don’t have a great pair or two of headphones then I’d strongly suggest you get them first.  Then when you want to make the your favourite headphone the very best it can be, maybe then have a think about the Solo Ultra, maybe give their home trial / loaner programme a bash and see if you like it as much as I have.
 
May 6, 2015 at 12:09 PM Post #2 of 56
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Graham Slee Solo Ultra Linear Quick Review
 
Thanks to Graham Slee for the loan.
 
Brief:  Teeny amp, giant name.
 
Price:  £670 or circa US$1020
 
Specification:  Lots, see here http://www.gspaudio.co.uk/soloultralinear.htm
 
Accessories:  Err none really, power supply if you count that.
 
Build Quality:  Good.  It’s a big block of aluminium which you can see the screws holding it together.  It’s sturdy and practical.
 
Aesthetics:  Pleasant, plain, perhaps a little utilitarian.
 
Sound:  Open, detailed, transparent and I could see some thinking it contradictorily either bright or valvey.  Bright because it’s so very detailed and this heightened clarity in the uppers makes the highs more articulated and readily distinct.  Rather than the smearing you get when there is a lot going on up top, the clarity retains all the detail making it more noticeable and hence could be interpreted as bright.  It’s valvey in the sense that the initial impact of metallic edges are a might soft.  The highly fluid smooth detail you get pervades everything and offers a hyper liquid presentation.  There isn’t any abrasiveness or harshness despite its very open and clear nature.  Normally you see, that “clarity” is enhanced by cranking up the abrasiveness so it “feels” more clear.  The Solo Ultra doesn’t do that, it does it the hard way by actual giving you more detail rather than just trying to trick your ears in to then thinking there is.  It’s pretty awesome.  The enhanced clarity is everywhere, from adding a certain vigour to the lows, they do reduce the tendency of headphones to bloom a little so you get a more well sculpted bottom.  It firm and luscious.  Mids share the same nudging, highly detailed, highly detailed pushing towards detail and nuance.  It does a little over do vocals which suit a more creamy presentation.  I can’t fault it for being too detailed but Nora likes a more rich and creamy experience, yes her vocals are super fluid but she isn’t about extracting every last detail she’s about melting away.  The Solo Ultra enjoys being desperately detailed and nuanced, not so much melty.  Highs are super good too.  Supremely detailed so feed it good quality stuff, while it does do a little valve esq softening of the metallic edge of a clatter but only a hint of it, feed it crap and it’ll try not to cheese grater your ears but if you buy this amp and feed it rubbish, it will assume you know what your doing and dish it up.
 
Value:  Eek.  It’s the best part of £700 here for a headphone amp.  So we are well into diminishing returns but….. if you’ve got some first class, kick ass headphones already and you want to see just how well they can shine, you may well want to get your wallet out and give them a bash.  It’s pretty damn fine.
 
Pro’s:   Sounds exquisitely good.  Eeks out every last drop of performance form your headphones.
 
Con’s:  Your wallet may not be best pleased.
 
May 6, 2015 at 4:00 PM Post #4 of 56

o0CosmoMemory0o

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A fantastic sounding headphone amplifier. Paired with the Bitzie and with both Bitzie volume dial and Solo volume dial at near maximum positions, my AKG K1000 (speakers fully open) was driven fully and sounded fantastic. The purity, musicality and spatial image were incredible. This headphone amplifier clearly identifies a poor performing headphone and I think it's likely to be amongst the best sounding headamps available to buy, at any price, if the user has the expectations of an audio engineer, seeking a profound lack of colouration. I only sold my Solo because I use the Proprius instead. The Solo drove my former HD800 effortlessly as well.
 
May 6, 2015 at 4:42 PM Post #5 of 56

Sefelt103

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Great review mark2410. It is hard to review something like a headphone amplifier especially when some subtle trait makes you prefer it over another one. Sometimes it is the price that makes us feel a device is brilliant. I owned the Fiio E9 and thought it was great until I tried other amplifiers. The E9 is bass and treble boosted and has a fair amount of colouration that some people adore. From what I know about Graham Slee amplifiers is they aim to sound like valve amplifiers with solid state circuits and obviously without the need to replace valves. I suppose they lack an element that valve amplifiers have in that you can't 'roll' different valves if you dislike the stock ones. Anyway nice insight into a classy headphone amplifier.
 
May 6, 2015 at 6:50 PM Post #6 of 56

Bansaku

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Nice review. I often come across the 'innards' of the Solo when using Google to look up amp boards and had always thought the simplistic textbook design always produces the cleanest sound. But that price; Wow is that steep! For what is under the hood it is overly expensive, even if all the parts are soldered on by hand. I wonder how much of an impact the PSU1 has on the overall quality of sound?
 
beerchug.gif

 
May 6, 2015 at 10:27 PM Post #7 of 56

volly

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I still have my Novo and swap it out every now again with my Asgard 2 but honestly the Novo sounds more energetic compared to the Asgard.
 
I would love to hear the Solo one day, as I hear it is quite a step up from the Novo. 
 
The PSU intrigues me, supposed to enhance the amp quite a bit, compared to the walwart (green) psu. 
 
Great review!
 
May 7, 2015 at 4:10 AM Post #8 of 56

Articnoise

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I agree this amp is nice; open, refined, transparent and smooth. I liked it better than the Soloist with some efficient headphones. It sure has more power than one would think if looking at the spec. Mark if it’s new you will get much better/smoother result after 2-3 weeks.

The good tube qualities comes from the no feedback design and the selected caps IIRC.

 
May 8, 2015 at 6:08 AM Post #9 of 56
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Graham Slee Solo Ultra Linear Quick Review
 
Thanks to Graham Slee for the loan.
 
Brief:  Teeny amp, giant name.
 
Price:  £670 or circa US$1020
 
Specification:  Lots, see here http://www.gspaudio.co.uk/soloultralinear.htm
 
Accessories:  Err none really, power supply if you count that.
 
Build Quality:  Good.  It’s a big block of aluminium which you can see the screws holding it together.  It’s sturdy and practical.
 
Aesthetics:  Pleasant, plain, perhaps a little utilitarian.
 
Sound:  Open, detailed, transparent and I could see some thinking it contradictorily either bright or valvey.  Bright because it’s so very detailed and this heightened clarity in the uppers makes the highs more articulated and readily distinct.  Rather than the smearing you get when there is a lot going on up top, the clarity retains all the detail making it more noticeable and hence could be interpreted as bright.  It’s valvey in the sense that the initial impact of metallic edges are a might soft.  The highly fluid smooth detail you get pervades everything and offers a hyper liquid presentation.  There isn’t any abrasiveness or harshness despite its very open and clear nature.  Normally you see, that “clarity” is enhanced by cranking up the abrasiveness so it “feels” more clear.  The Solo Ultra doesn’t do that, it does it the hard way by actual giving you more detail rather than just trying to trick your ears in to then thinking there is.  It’s pretty awesome.  The enhanced clarity is everywhere, from adding a certain vigour to the lows, they do reduce the tendency of headphones to bloom a little so you get a more well sculpted bottom.  It firm and luscious.  Mids share the same nudging, highly detailed, highly detailed pushing towards detail and nuance.  It does a little over do vocals which suit a more creamy presentation.  I can’t fault it for being too detailed but Nora likes a more rich and creamy experience, yes her vocals are super fluid but she isn’t about extracting every last detail she’s about melting away.  The Solo Ultra enjoys being desperately detailed and nuanced, not so much melty.  Highs are super good too.  Supremely detailed so feed it good quality stuff, while it does do a little valve esq softening of the metallic edge of a clatter but only a hint of it, feed it crap and it’ll try not to cheese grater your ears but if you buy this amp and feed it rubbish, it will assume you know what your doing and dish it up.
 
Value:  Eek.  It’s the best part of £700 here for a headphone amp.  So we are well into diminishing returns but….. if you’ve got some first class, kick ass headphones already and you want to see just how well they can shine, you may well want to get your wallet out and give them a bash.  It’s pretty damn fine.
 
Pro’s:   Sounds exquisitely good.  Eeks out every last drop of performance form your headphones.
 
Con’s:  Your wallet may not be best pleased.
  Nice review. I often come across the 'innards' of the Solo when using Google to look up amp boards and had always thought the simplistic textbook design always produces the cleanest sound. But that price; Wow is that steep! For what is under the hood it is overly expensive, even if all the parts are soldered on by hand. I wonder how much of an impact the PSU1 has on the overall quality of sound?
 
beerchug.gif

yeah thats an interesting question,  part of me want to try the two to see what if any difference, im rather skeptical as to what difference there could be.  though having a good quality powers supply that wont fry your amp if there was a power surge or soemthing is prob a good idea.
 
 
I agree this amp is nice; open, refined, transparent and smooth. I liked it better than the Soloist with some efficient headphones. It sure has more power than one would think if looking at the spec. Mark if it’s new you will get much better/smoother result after 2-3 weeks.

The good tube qualities comes from the no feedback design and the selected caps IIRC.

oh it was their loaner unit so it should have had tons and tons of hours on it already, so no danger there.
 
May 14, 2015 at 9:02 PM Post #14 of 56

Jodet

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  It's certainly a handsome piece of kit, but >$1000 for a SS amp in 2015... Don't get me started. 

 
It's a nice looking piece of gear and I'm going to listen to it on the loan program.    But yeah... I'd be happier if it were $999 at most. 
 
I guess that's the price for having something made in England instead of China.  
 
But still...... 
 

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