Not all component combinations are predictable. Sometimes you find an amp and speakers that despite coming from different schools of audio thought seem to gel in ways that few would have expected. On this occasion, the amplifier and speaker in question are in the form of the mighty ATC SCM150 ASL, a ‘fridge on a stand’ scale loudspeaker with a hefty power amplifier on its back. But the preamplifier – though that name is insufficient to describe the wealth of features on offer – is from Scandinavian electronics experts Primare. And as a combo it works with considerable aplomb.
The Primare PRE60 is the company’s flagship preamplifier. It’s built to a very high standard with typically Nordic restraint in the styling department, not that the two tone fascia isn’t striking as a result. The PRE60 has many functions but you have to scroll through the input names in a cool, clean sans serif font to realise how diverse they are. It is an analogue preamplifier with single ended and balanced in- and outputs, it is a digital-to-analogue converter with S/PDIF and USB inputs, and finally it is a network streamer that is controlled by with Primare’s own app for iOS and Android. All you need to add is a NAS drive packed with your favourite tunes and you have a complete front end that is not only formed of one box but is also very nice to operate. You can use either the app or a remote handset to control input selection and volume and the OLED display is so clear that it’s legible across the room.
Setting up the app for the media player (as Primare calls the PRE60) is very easy, it takes two minutes at most once you’ve connected the PRE60 to the network. Initially the volume on the app is a bit odd, but once the knack is learnt, it’s possible to make very small level changes, which is not always the case with such devices. It is one of the benefits of proprietary control software that third party apps can never offer without compromising sound quality. There are a few minor gripes with the app, I would have liked an A-Z listing for artists, albums, etc., but a column of dots works in a similar way. It only displays in portrait mode but that’s hardly disastrous, and the only thing that continues to irk is the speed (or lack thereof) when displaying titles. This might be less of an issue with smaller libraries or with more powerful tablets than an iPad Mini, but it’s not something that other apps do.
The ATC SCM150 ASL is a ‘proper’ loudspeaker; a foursquare block that makes no concessions to the contemporary fashion for slim baffles and minimal domestic intrusion. Instead, it is an unpretentious, call a spade a spade, no nonsense loudspeaker. The bass driver is a full-fat 380mm driver that takes up the majority of the nigh on half metre wide front baffle. There are studio and domestic versions of this model; in professional circles they are often soffit mounted, but I wouldn’t want to be installing all 75 kilos in a wall, especially any wall higher than the 250mm high steel stands they come with. Even that’s a two‑man job. Although this model has been in the catalogue for sometime now, ATC’s development of its own tweeter means that the SCM150 ASL is not the same beast as it once was. In fact, it’s a lot better. ATC has ‘form’ in drive unit making: the company has been making its ‘super linear’ bass drivers and midrange domes for many years, but only recently has a tweeter gone into production at the facility near Stroud in Gloucestershire.
There are two ATC tweeters both called SH25-76, the standard version being fitted to models up to the SCM40 ASL and the S version in those above it. The SCM150 ASL therefore has the SH25-76S, a 25mm soft dome with higher efficiency and lower distortion than its counterpart, which offers 25% more magnetic flux density and 3.5dB greater sensitivity. When I asked ATC engineer Ben Lilly why they felt the need to build their own tweeter, he explained that it’s the only way to get precisely the driver you need rather than a third party manufacturer’s idea of how it should be made.
The amplification is also designed and built in-house and consists of three channels per speaker with 50 Watts for the tweeter, 100 Watts for the midrange, and 200 Watts for the bass. This is combined with an electronic crossover that hands everything below 380Hz to the bass driver and everything above 3.5kHz to the tweeter. Connection is by XLR only, as befits a speaker that comes from the studio world.
As you might imagine it’s the bass that first grabs you with this system, but it doesn’t do so in an overpowering or excessive way like a subwoofer turned up to 11. Instead you can hear all the timbres of bass instruments and all the nuances of the way they are played; it’s almost the opposite of bass created by smaller speakers where definition is exchanged for thick, heavy, and unnatural lows. This ATC is so clean and even handed that only truly low notes produce real gravitas, there is no excess, no flab, just girth. When you connect 200 Watts directly to the driver that it has been made for, you get astonishing control and that means extraordinary detail, coherence and, importantly, extension. This speaker does make you start looking for albums with serious low end on them, but it takes no prisoners in revealing which albums actually go down deep, and which are just tweaked to sound that way on most speakers.
Put on Koyaanisqatsi [Philip Glass, Nonesuch] for example, and the organ notes are deep and clear, the male voices full of tonal subtlety and the soundscape expansive. More important is that the music makes sense, the absence of thickness in the bass allows the tune to take precedence over the sound, it allows the message in the music to be communicated in a way that most systems struggle with because they don’t have the resolution and control that this one does. It’s not just the speaker either; the PRE60 is a critical part of the result. It is extremely quiet and produces a far more expansive image than others of its ilk. The high notes are really well extended, but clean and revealing, while cymbal harmonics are brought out of the mix alongside other quiet sounds because the noise floor is so low.
It is interesting to contrast the sound of the USB input with the network or server input; in most cases USB has a more ‘hi-fi’, but ultimately less engaging, and well timed sound, but here the network sound excels in both resolution and timing. Obviously this result will vary with different sources, but I made it using the same source (Melco N1A) and could hear more via its direct Ethernet connection and found the timing more taut and clearcut. With electronic sounds such as Boris Blank’s ‘Electrified’ [Electrified, Polydor] the presentation takes on a whole new dimension; there is clearly a lot of phase manipulation going on in the mix, but rarely has it been so well resolved. The use of space is fabulous – nearly as fabulous as the power of the synth bass, which is proper internal organ vibrating stuff. On less visceral material like The Civil Wars acoustic guitar and voices [Unplugged on VH1, Sensibility Music], the resolution of timbre, detail, and playing/singing is what counts. Never has the buzz of steel strings and the temporal precision of their ‘Billie Jean’ cover been so effectively presented.
It’s worth noting that my listening room is not very wide, 3.5m for the most part, yet on this system never is there any sense of the bass being too much. Even with less than 50cm to rear walls, and not a lot more to the sides, the bass is very tidy and controlled. This is not often the case with ported speakers; but most of those aren’t active, nor are they ATCs. The new tweeter is a boon as well, as it’s more revealing yet sweeter than the SEAS unit it replaces. This speaker used to be a bit ‘warts an’ all’ for anything less than smooth, clean electronics and recordings, but the tweeter has made the 150 a whole lot more charming without losing transparency. The Primare is a very impressive piece of kit, too; this is where the fine detail in the sound is coming from and the fact that it can produce such a stunning result while combining so many functions is very impressive indeed. You can get streamer/preamps for less, but rarely with so many features and never in my experience with such clarity and precision. The Primare/ATC pairing is not an average one in any sense of the word.
ATC SCM150 ASL
Type: 3-way, two-driver active, stand-mount monitor with front-ported bass reflex enclosure
Driver complement: One 25mm soft dome tweeter, one 75mm soft dome mid-bass driver, one 375mm doped paper bass driver
Amplifier output: HF 50 Watts RMS, MF 100 Watts RMS, LF 200 Watts RMS
Frequency response: 25Hz–22kHz (–6dB)
Crossover frequency: 380Hz, 3.5kHz
Dimensions (H×W×D): 884 × 498 × 568mm
Finishes: Walnut Burl veneer, Piano Black, High‑Gloss White, all possible paint colours
Price including stands: £17,647/pair (black ash), £18,042/pair (cherry/walnut), £20,375/pair (yew/rosewood)
Manufacturer: ATC Loudspeaker Technology
Type: Balanced preamplifier, network streamer and DAC
Analogue inputs: Two pairs of balanced inputs (via XLR connectors), four single-ended inputs (via RCA jacks)
Digital inputs: USB A, USB B, three optical S/PDIF inputs (via Toslink), one coaxial S/PDIF input (via RCA jack), network connection (via RJ45)
Analogue outputs: Two pairs of XLR balanced outputs, two pairs of RCA single-ended outputs, one pair of RCA single-ended Tape Outputs
Input impedance: 15kOhms
Output impedance: 110 Ohms
Bandwidth: 20Hz–100kHz, –3dB
THD: < 0.003%, 20Hz–100kHz, 0dB gain
Signal to Noise Ratio: –115dBV
Dimensions (H×W×D): 142 × 430 × 385mm