Graham Slee Solo SRG II - Reviews
Graham Slee Solo SRGii - Hidden Gem
Pros: Good Clean Power, Versatile enough to drive range of Headphones, Low Noise Floor
Cons: Did not notice any so far
It has almost been a month since I got my first desktop AMP, the Graham Slee Solo SRGii (Studio Reference Green MK II) and I am sharing some of my impressions based on my limited chain and listening experience.

I purchased the AMP with my own money from Goldfinch Acoustics as they are official dealer of Graham Slee products in India. Following observations and impressions are my own and are based on my limited experience, Gears & choice of music; and are not influenced by anyone in any way.


Solo SRGii is housed in a strong and sturdy aluminum enclosure that looks simple yet premium, and feels solid in hand. It carries a rather smaller footprint which makes it very convenient to place the AMP anywhere without worrying about space (something that mattered to me given limited desk space). It comes with an external energy efficient power supply and I guess that's what the 'green' part in its name refers to. There's also an option to upgrade the power supply unit to a more premium PSU1 which is available at an additional cost.


There are two RCA inputs at the back and an input selector on the front panel in form of a toggle switch with center off position. There’s a single full size 6.35mm headphone jack in the front with a volume knob, and a small green LED. There's also a DC input slot at the back that allows you to connect the power supply. According to specs, the amp is designed to automatically cater to headphones of any impedance from 16-600 Ohms and for input levels between 250mV and 1V, so there's no gain control option. The volume knob also acts as sensitivity adjuster and therefore the full rotation can be used with different headphones

Before talking about sound, I must mention that I am not an expert audiophile and my exposure to desktop gear has been very limited, therefore do not expect any comparisons or benchmarks. I have only been using portable devices for past few years (DAPs, IEMs, DAC/AMPs) and am just starting to explore full size HPs with desktop gear.


My only headphone as of now is Focal Clear and I was happy using it with portable sources. Clear is fairly easy to drive but I am amazed how well it scales with a better AMP (GS in my case). I am hearing more openness and clarity in sound with outstanding micro details & dynamics that I never heard before. The treble on the Solo is awesome, very well extended, grain free and without any harshness or sibilance. Mid-range is wonderfully open and airy with great details in Vocals without making it ear piercing. Bass is fast and punchy but not dominating. Overall sound is smoother and more relaxed which is great for long listening sessions without causing any fatigue. Focal Clear does not have a very wide soundstage but I did observe wider staging on Clear with the Solo as compared to other portable sources I used earlier. The imaging gets a lot better and the instruments sound much more prominent.


I tried the AKG K240 Sextett (Loaner Unit) and I was pleasantly surprised how efficiently the Solo was able to drive it without any distortion. Of course, at 600 ohms the Sextett needs power and may sound better with more powerful AMPs however in my limited usage I did not find anything lacking. In fact, I enjoyed the beautiful mid-range on the Sextett even though I do not prefer mid-centric sound signature.

To summarize, overall listening experience is very immersive and non-fatiguing. Such airy top end that doesn't feel bright, wonderfully open midrange and a low noise floor. Great resolution and extremely detailed sound overall. GS Solo SRGii in my opinion is very versatile and a suitable amplifier if you intend to try a range of headphones and various music genres like Bollywood, Pop, Rock, Instrumental, Classical etc. However, if you are someone who's only into more energetic music like Hard Rock/Metal, of if you have some real power-hungry cans to drive you may want to try other options.

Graham Slee Solo SRGii offers great bang for the bucks and is definitely worth a listen.
Glad to see you got the Slee Aakash - welcome to the club!
Thanks for your impressions and enjoy your new amp.
Pros: Smart
Cons: Still not clear enough for me
It's sound is nice, but still not  precise  enough for me.
Pros: hand made, great sound quality, high detail
Cons: pricey
"The Solo SRG II headphone amplifier has two line level inputs and a front panel input selector with centre off. It is housed in a strong anodized aluminium eurocard style enclosure. The volume control also acts as sensitivity adjuster and therefore the full rotation can be used . The Solo SRG II headphone amplifier is suitable for use with headphone impedances from 16 Ohms to 600 Ohms."
I bought this amp unheard based on the rave reviews from English hi-fi magazines and it did not disappoint. It runs my Grado 325i's as well as my HD650's beautifully. As stated above the volume acts also as a sensitivity adjuster so with the 300ohm HD650's i run it at the 3 or 4 o'clock position and the 32ohm grados at 12oclock.
My reviewer vocabulary is not good enough to describe sound characteristics but i do know it was leaps and bounds better than the Firestone fubar IV Plus that it replaced. (Please see the professional reviews in the link provided for better information)
A  word of advice for anyone wanting to purchase one of these. Buy the PSU1 power supply that is available as a combo. It is cheaper to purchase than if you are buying separately which I did.(US$350) After listening to my amp with the walwart type supply i decided to spring for the upgraded PSU and it made a significant and very noticeable difference in sound quality. Everything was suddenly more vibrant.
Overall I am very pleased with my purchase and am happy knowing that if i decide to keep it for many years it will still be a good quality amplifier.
Please note prices are converted from New Zealand dollars based on today's exchange rate. It may be available cheaper in the US.