Posted on Tue, 04 Nov, 2014
Posted by Peter

Graham Slee

What makes a real hi-fi brand? Is it the awards and the accolades? Is it the number of units sold? Or is it passion and dedication to the cause? We’d argue that real hi-fi is defined by passion – and Graham Slee have that in bounds.

Specialising in headphone amplifiers and their upgrades and accessories, they operate in a very specific niche. Because their skills and resources – not to mention their knowledge, passion and expertise – are acutely focused on this niche, the products become objects of pure mastery. When a brand spreads themselves too thin in terms of range, it has been known for the quality to suffer. The same goes for brands that focus on mass production and huge profit margins. It’s not always the case – of course – but sometimes brands which only see the figures can lose sight of what’s really important.

Graham Slee are not one of those brands. Quite the opposite, in fact. They are a very small British company and their commitment is to their craft: producing high quality, hi-end headphone amplifiers, is their focus. The result is what we believe to be a real hi-fi brand. And to celebrate this brand and their talents, we have composed a list of our top five. And they all come with our heartiest recommendations. If you’re in the market for a top notch headphone amplifier, the items below are a very good place to start. And finish.

Remember, all prices were correct at the time of publishing and may be subject to change.

1. Graham Slee Novo Headphone Amplifier – £249


We’re kicking things off with a budget model that has managed to scoop a number of awards – including What Hi-Fi?’s Best Headphone Amplifier Award! The little Novo is an exceptional amplifier which is compact in size yet big in power and sound. It’s a very simple design, featureless aside from an input, volume and an output – so you can ‘daisy chain’ this between your source (streamer, CD Player, DAC etc. and your amplifier/speakers, to use as and when you fancy. You can even plug it directly into your pre=amp, so you can switch between speakers and headphones with ease.

Why do we like it?
It’s been fine tuned to the smallest detail to get the absolute most out of its sound. A great buy whether you’re on a budget or not, and a firm favourite here and pretty much everywhere else (… that requires headphone amplification).

Why do they like it?
Good with dynamics, tonally accomplished, great detailing, ease of use…In terms of dynamics, this feisty Novo can handle just about anything you can throw at it. Add a good sense of timing and essentially you’ve got everything you need in a headphone amplifier. (What Hi-Fi? Magazine)

2. Graham Slee Bitzie USB DAC/USB Headphone Amplifier – £349


Hidden inside the little Bitze is the key to turning your PC into an audio-hub you can be proud of! It functions as both a hi-end DAC – improving upon the sound card in your PC and enhancing the sound quality of any digital file – and a headphone amplifier, all-in-one. It’s plug and play, which means it requires no driver downloads! It features both optical and coaxial outputs and boasts a full-speed USB.

Why do we like it?
We like anything that makes achieving real hi-fi sound less of a hassle – and the Bitzie does this with grace and finesse. It’s a very new product – the newest product from GS – and we have every confidence that everyone who uses it will love it.

3. Graham Slee Solo SRG II Green Headphone Amplifier – £405

Graham Slee Solo SRG II Green Headphone Amplifier

The Solo SRG II is the latest version of a product derived from GS’s Intro – which proved to be one of their most popular products ever. Still within the realms of ‘budget’, the Solo SRG II effectively brings out the hidden depths, textures and details within any type of music – with any type of headphone.

Why do we like it?
It’s a sublime little headphone amp, and one of our absolute favourites when paired with the Grado RS1, the Oppo PM2, and the Sennheiser HD650. As a nice little bonus, this unit comes with the Grado 4.5m Headphones Extension Cable – worth £37.50 – for free.

4. Graham Slee Solo SRG II MC Headphone Amplifier – £509.95

Graham Slee Solo SRG II MC Headphone Amplifier

The more eagle-eyed of you may have noticed that this model is strikingly similar to the one above. Well, that’s because it’s the same as the one above. But with one key difference: it comes with the Graham Slee PSU1 Power Supply Upgrade which is also available separately (so you can upgrade your SRG II whenever it suits), but buying the two together works out much cheaper. This upgrade monitors the spikes and variations that exists in any standard power supply – which can have a negative effect on your listening experience – and regulates for a smoother input. This upgrade will allow you to enjoy your Graham Slee amp to its absolute fullest potential.

Why do we like it?
It’s like the product before, only better! And buying one of these with the upgrade pre-installed saves you a few quid over buying the upgrade separately.

5. Graham Slee Solo Ultra Linear Diamond Edition Headphone Amplifier – £655

Graham Slee Solo Ultra Linear Diamond Edition Headphone Amplifier

And finally – the flagship! This is what an award winning specialist in headphone amplifiers deems to be their greatest achievement – and it truly is. With an ultra-wide bandwidth (even before the application of ‘negative feedback’ which headphones amps use as a counter to distortion), greater input linearity, minimal restructuring around the negative feedback. Thanks to this, what you’re hearing is the music as truly as possible – with practically no distortion, and certainly none we;ve been able to make out when auditioning. This comes with Graham Slee PSU1 Power Supply Upgrade fitted as standard too.

Why do we like it?
It’s one of our favourite headphone amplifiers – and partners beautifully with everything we have matched it with. When partnered with Sennheiser HD800, Oppo PM1 or Grado GS1000e headphones, it is about as close to audio excellence as you can get!

Why do they like it?
‘The Solo Ultra-Linear Diamond Edition is a piece of audio artwork wrapped up in a compact brushed aluminium unit. Plonking itself right in the mid-range section of amps on the market today, Graham Slee has created a piece of audio brilliance that allows the listener to immerse themselves fully in to the audio working it’s way through the ear canal’ (


It all started, as it often does, with a man. One Graham Slee. Born in Doncaster, Slee worked in audio-visual engineering up until 1984. His first business was a electronics and printed circuit business, which he closed in 1989 to take up the position of senior engineer at Audionics, where he designed circuits for broadcast audio, where his many clients included the BBC. He left in 1993 to undertake five years of freelance work with various companies, expanding his skillset and eventually gathering what he needed to form his own company, also known as GSProjects, in 1998.

His first release was the in 1999 when he designed and built his first commercial phono stage known as the ‘Basic’ which was later changed to the Gram Amp, or the  ‘Gram’ , as it clashed with a competing product. The Gram received great praise from the critics of the time, and spawned another three versions, of which were extremely popular in the USA.

However his headphone amplifiers – which began with the Solo in 2001 – didn’t take off until they were discovered by the Chinese market. And once word was out there, it spread like wildfire. By 2004, Slee was joined by a team who – between them – has over 100 years of experience in the industry. Shifting their expert focus onto headphone amplifiers – they set to work at building up the brand we know today. And it’s all driven by one very clear goal:

Our products must handle all types of music to the highest performance levels – no tricks – no musical effects – just true musicality achieved by the highest fidelity electronics available today.’