Driving Ability

Now with specs like the 909 there was little doubt of their ability to handle a driver, and I can confirm they do so very well indeed. It hasn’t mattered whether it’s been a high impedance headphone like the HD800 or a rather demanding planar like the ZMF Blackwood, the 909 has never sounded out of breath, not once. Another headphone that has been driven well is the Ultrasone Edition 10, a headphone that has got a bad rap, unnecessarily so if you ask me, but that’s a conversation for another day. Anyway, no problems with driving these, I would hesitate before using an HE6 or Abyss, I think you’ve really got to be approaching 5 Watts with these, especially the HIFIMAN’s. The 909 does just great with more sensitive headphones like the BeyerDynamic T5P too, yes there is a bit of a dull hiss in the background but the T5P will draw that from pretty much every full sized desktop amp I’ve tried. The only thing I will warn against is the use of IEM’s with this, OBVIOUSLY that isn’t what it’s designed for but people do it believe it or not. It won’t sound good, ok. 

We’re doing well so far, great specs, attainable price tag, solid build and confidence in driving almost any headphone…


As I have mentioned the sound testing has been conducted with a range of headphones including HD800’s, Edition 10’s, Blackwoods, HD600’s, T5p etc. as well as direct comparisons to amps from Questyle, COS and Yulong. Throughout the testing the 909 has shown a subtle but apparent signature, and that is a slight uphill slope towards the upper mids and treble, but it is only a slight emphasis, it’s pretty darn flat in reality. What this does is make for a wonderfully clear and well defined headphone amplifier that is technically very good and also a really enjoyable long term listen. 

The comparison to the Questyle amplifiers was against them both as mono-block configuration and individually. The mono-block test was hardly fair as it’s effectively a £3800 product so more than double the price, but the 909 genuinely did hold its own. The Questyle’s were superior technically but believe me the biggest factor here was still synergy. The HD800’s have always had an amazing connection with the Questyle’s but I must say the ZMF’s were sonically more to my preference on the 909. This is no small feat and should start to give you an idea of the quality this amplifier has.

When comparing the two individual amplifiers it becomes a much fairer fight in terms of price, with both products being just under £2k. With the HD800’s and the modded HD580’s there are no surprises, the synergy is still great with the CMA800R, but with the ZMF’s, T5P’s and Edition 10’s it is a different story and both choices will appeal to different people. 

Where the Questyle’s shine is in their sheer expanse of the soundstage, something that the 909 cannot match. The Harmony has fantastic instrument placement though, and the precision in which it paints its picture is great, whatever the headphone you choose. The 909 has a very firm grasp on the music and I have never felt it to become sloppy or ‘out-of-control’ at all. When A/Bing between the two the Questyle does sound a little woollier around the edges and arguably not as refined. Detail retrieval is great here too! 

Where the 909 potentially falls short is when it comes to out-and-out involvement in the music, its more technical than it is musical but this is where my preference would sit. I voice my sound with my headphone/speakers, my amp should impart no signature. While the 909 is definitely a leaner signature with a very slight upwards tilt, it is definitely closer to my ideal than a lot of other headphone amplifiers in this range. 

Talking more specifically about the sound, the bass is quick and punchy with decent depth and feel. It doesn’t extend as well as it could in to the sub bass regions and does feel a little empty right at the bottom. That is arguably the only flaw with the 909 and it really isn’t something that massively detracts from the music, it’s only when you really listen critically that you notice. Moving on from that, the speed and definition of the bass is really what it’s all about at the bottom end. There is a distinct slam when it is called for and the shorter decay really emphasises this. If you’re a bass head that wants a really warm enveloping bottom end with exaggerated rumble and depth it is fair to say this won’t be for you.

Before we keep breaking down the sound of this amplifier we would like to clarify we are aware that if you was to measure this amp it would be fairly flat, but that does not mean it will sound identical to every other amp…. 

The mid band is where we start to see the increase in presence, especially towards the female vocal range. The lower mid-range maintains the great control and precision like in the bass but also give better feeling and more of a musical nature too, especially with male vocals. As I said moving up from there we have a great sense of clarity and spaciousness which is helped by the upper mid presence. This area really does sing and there is no veil at all, something that is very clear when you start to switch sources around. 

The top end remains as prominent as the upper mids which can often cause problems when overdone. As I have said this signature on the 909 is very subtle, but it’s not just that which means this sound is enticing as opposed to problematic. It’s the control, even with notoriously brighter headphones like the Edition 10’s and sometimes even the T5P the 909 keeps them composed, delicate and accurate without ever restraining anything. This level of control is common throughout the sonic spectrum and I can’t tell you exactly what is causing it, whether it’s the great power supply, circuitry or simply that it’s just a very well designed amplifier. Whichever it is, the 909 has more top to bottom control and precision than any sub 2k amplifier I have heard.

To finish this section, you must know the 909 offers that balance of transparency where you have a great insight into the music without forcing you to have a 5k source and I think in this price range that’s extremely sensible. Whether I used my AK240SS with a balanced LabKable connection (around £2750) or the BMC PureMedia into totaldac as a source (around £15,000), the 909 worked just great, proving itself to be a really competent amplifier in all accounts. 



The little guys in this industry are often creating some of the best gear per pound and I have to say this commonality continues with the 909. Its signature just a touch leaner than neutral but the precision and sonic abilities will impress whatever your preference. At approximately £1750 the 909 is one of the finest all round sub 2k headphone amplifiers around.

The design will put some off, as will the idea of owning a piece from an unknown brand, but I highly recommend taking a much closer look at the Swedish offering, you might just be surprised!

For these reasons the 909 gets our good buy award.


Turn the page for some further reading from Mattias himself….

Josh Coleby