On paper, the Rotel RA-12 seems a lot like the Award-winning RA-10 (£350), with the addition of a built-in DAC, Bluetooth connectivity, and increased 60W per channel output. But switch it on and its character is subtly different.
Rotel RA-12 review: Performance
Like its little brother, the RA-12 is evenly balanced, reaching satisfyingly deep into bass, while the midrange is articulate and controlled. It shares a similar tonal balance with the RA-10, along with a good dose of detail and precision, but it doesn’t have the dynamic thrust and crisp rhythmic ability that makes the cheaper amp so engaging.
You’d expect the £600 RA-12 to surpass the strengths of its budget sibling, but play Amanda Palmer’s Runs In The Family via the analogue inputs and it isn’t fully expressive of her attitude-laden vocals.
The RA-12’s soundfield could have a touch more depth and openness, and the mellow glow that we loved so much in the RA-10’s phono stage isn’t as forthcoming here.
Switch to the digital inputs (there are two optical and two coaxial sockets) and the results are broadly consistent, but the sound is slightly brighter, which adds a touch of sparkle. The line-level connections offer a much richer listening experience, albeit a restrained one.
Rotel RA-12 review: Features
In addition to the four digital inputs, the Rotel has five line-level inputs (including moving magnet phono), two sets of speaker outputs and preamp outs.
There's also a mini-USB socket round the back, but before you get all excited about this providing a computer audio hook-up, hold your horses – it's there only for future firmware upgrades.
Speaking of digitally-stored music, also worth noting that while the front-panel input can accept content on memory devices, its capability is somewhat limited: it'll only accept AAC(m4a), MP3, WAV and WMA (up to 48K 16 bit).
So if you want to play FLAC or Apple Lossless files off a memory stick, as we did at the launch of the 12-Series products down at Rotel distributor B&W in Worthing a while back, you'll be scuppered.
However, the built-in Wolfson WM8740 DAC supports files up to 24-bit/192kHz via the conventional digital inputs, so higher-resolution files could be played into it via a computer with a digital output, or one combined with a suitable USB-to-S/PDIF interface.
That front USB also allows Bluetooth connectivity, using a dongle included with the amplifier. It's not as elegant as an 'under-the-hood' Bluetooth implementation, agreed, but it does the job.
Other connectivity extends to two 12V trigger outputs to control external equipment, while there's also a Rotel Link socket, enabling the RT-12 'Digital Gateway' to control the amp via a 3.5m-plug-terminate cable.
There's also a headphone socket on the front, along with a prominent display, and the Rotel is supplied complete with the company's RR-AX91 remote handset, which can also 'drive' basic functions of the company's CD players and tuners.
Using the display and the remote, it's possible to adjust and store the bass, treble and balance, and set up the volume level at which the amplifier fires up from standby.
It's also possible to dim the display in seven steps, and determine how the amp connects to a CD player in a complete 12-Series system, using the Rotel Link CD function: you can choose 'CD', which uses the analogue connection, or 'CX1' or 'CX2', which select the respective coaxial digital inputs.
Rotel RA-12 review: Build
As is usual for Rotel components, the RA-12 is built around carefully selected and custom-made components.
The power transformer (above) is of a custom design, engineered and manufactured in-house as part of a low-impedance supply with generous reserves, and signal paths are kept short and symmetrical in the quest for the purest possible signal.
There's also extensive protection against overheating or short-circuiting of the speaker outputs: this will illuminate a front-panel LED should it ever be triggered, as well as shutting down the amp. However, this protection is kept independent of the audio signal, working by monitoring the temperature of the output devices.
For the same reason, the amplifier comes out of the box with its tone controls bypassed, as is indicated on the front panel display. To use the tone controls via the menu system, you first have to deselect this bypass.
Finally, even the headphone implementation is designed to keep it out of the sonic equation, as is usual with Rotel amplifiers: inserting a headphone plug won't shut off the speaker outputs, and you need to turn the speaker selector to 'off' for private listening.
Rotel RA-12 review: Verdict
The exhaustive features are a great point in the RA-12’s favour, and there’s enough going on sonically to keep you listening. It isn’t a true star at this price level, but remains worthy of consideration if you crave an amp with such a well-packed bag of tricks.
