We’ve been waiting a long time for Rotel’s RA-12. First for the company to finalise its move into its new wholly-owned factory in China (along with key personnel from the UK, China and Canada) and then for the brand-new ‘brainy’ RA-12 to progress from the drawing board into full production. And then for one to arrive here in Australia, so we could hear how it performed. The good news is that it’s been worth the wait…
And in more good news, the RA-12 has gained some chassis height compared to the RA-10, which always seemed too low-slung to us. (We also reckon the new 12 Series components are nicer-looking than those in Rotel’s 15 Series, but maybe that’s just us.) The third bit of good news is that the RA-12 has gained a boost in power output over its predecessor. Sure the RA-10 always delivered far more than its modest 40-watt per channel rating, but the RA-12 promises a minimum of 60 watts as its ‘spec’. And, like every other Rotel amplifier we’ve ever seen, it delivered far more on test: in a test performed by Australian Hi-Fi Test Labs our sample model RA-12 was measured as delivering 74W per channel, into 8 ohms, both channels driven.
Fourth, the RA-12 now has a DAC on-board: and not just any DAC; Rotel is using the very highly-regarded Wolfson Microelectronics 8740 24-bit/192kHz, which is exactly the same DAC used in a great many of the world’s ‘highest-end’ products from companies such as Red Wine Audio, Cambridge Audio and others. Which means, of course, that you can input digital signals via USB or SPDIF, as well as the more traditional analogue sources, for which the new RA-12 has plenty of options available, with four line-level inputs as well as a phono input for those who plan to use a turntable.
Fourth… and this will perhaps be of the greatest interest to many readers… the RA-12 is now able to be controlled from your iPhone or iPad. At least that’s what Rotel advertises, though if you look at the fine print, in order for you to be able to do this, you also need to own a Rotel RT-12. An RT-12 will set you back $899, but in addition to being the go-between that connects the RA-12 to your Wi-Fi network so the App can control the amplifier, Rotel’s RT-12 is also an FM/ DAB+ radio tuner and music server, so you can use it to play audio files stored on UPnP servers as well as stream internet radio.
If, on the other hand, you’re perfectly happy using a standard infra-red remote control to operate the RA-12, one of these is provided with every amplifier for free. And, if you’re just looking to stream audio from your smartphone to the RA-12, you can do this without spending any money at all, because Rotel includes with every RA-12 a Bluetooth ‘dongle’ that plugs into the USB input on the front panel. As you can see, all of this makes for a very flexible package.
Operation of the amplifier is superbly intuitive thanks to the ‘direct selection’ source-select pushbuttons below the front-panel display.
And once you’ve selected a source, your choice is shown in the top left of the display. Your selected volume level is shown in the right of the display as a read-out from 1 to 95 (‘Min’ or ‘Max’ is displayed if you exceed these limits). Volume is controlled not only from the front panel control, but also from the remote (or your iDevice). If you use the remote (or Rotel’s App), you get the added bonus of a mute function, which is not available from the front panel.
Some functions on the RA-12 are not direct-select, such as those for control of treble, bass and balance. These are accessed by the Menu/Up/Down buttons to the right of the display, and although the menu is layered, it’s really easy to navigate. We really liked the fact that Rotel has included a tone control bypass circuit setting, so after you’ve preset the bass and treble controls, you can bypass them if you like, while leaving the settings themselves intact, so that when you re-select the tone controls, you’ll pick up the same settings.
The Menu is also used to change the contrast ratio of the front panel display, alter its absolute brightness, choose how your CD player is connected to the amplifier (analogue, coaxial 1 or coaxial 2) and specify a power-on volume level. We were curious as to why we needed to set a power-on volume level until we realised that unlike many modern amplifiers, the Rotel RA-12 does not have an automatic standby mode: users are required to force the amplifier into standby by pressing the ‘Off’ button on the remote control. Using the power button on the front panel turns the amplifier off completely.
Over to the left of the front panel are a Speaker Selector (Off, A, B, A+B) and a headphone socket. Somewhat inexplicably, this is a 3.5mm type, rather than the full-sized 6.35mm socket we usually see on hi-fi amplifiers. If there’s a MkII version of the RA-12, we’d prefer a full-sized headphone socket. Interestingly, plugging headphones into the socket does not mute the speakers: if you want to listen quietly, you’ll need to turn the speaker selector to ‘off.’)
Under the headphone socket is a standard USB input which accesses the Wolfson WM8740 DAC within. This USB is designed to play music files stored on standard memory sticks or drives, though is restricted to playing MP3, AAC, WAV and WMA files (16-bit/48kHz maximum). If you want to play higher-res files, or FLAC or ALAC formats, the Wolfson can handle them but only if you use the digital inputs on the rear panel (optical or coaxial).
Speaking of the rear panel, you’ll find it’s nicely laid-out with good-quality fittings… though we thought the speaker terminals a bit dated, despite being gold-plated. In addition to the inputs you expect to find given the front-panel layout, you’ll also find a dual 12V trigger output, a Rotel Link connector, and a mini-USB socket. This last is not a duplicate of the front-panel USB input, it’s designed solely to enable easy software upgrades. There are also pre-out terminals… very nice.
The bass from Rotel’s RA-12 was solid and satisfying, we suspect in part because the company places so much importance on its power supply stages, to the extent of manufacturing its own toroidal transformers in its own factory, and having storage capacitors made specifically for
it (two 10,000µF ones are used in the RA-12, along with a standard rectifier bridge). Then there’s the fact that although Rotel was one of the last hi-fi manufacturers to introduce Class-D output stages into its audiophile amplifiers, the RA-12 has a traditional Class-AB output stage, using Sanken A1695/C4468 epitaxial planar transistor pairs, mounted on a very substantial section of good-quality heatsinking, so there’s no need for fan-cooling.
Play any track with decent bass and you’ll hear straight away that the RA-12 responds instantaneously to variations in pace and timing, as well as to the demands of volume level, no matter whether that demand is continuous or transient. Even excessive demands in the bass department didn’t unsettle the amplifier’s performance in other areas, with the treble in particular remaining sweet and refined.
High-frequency extension was exemplary; the RA-12 isn’t going to be a weak link in the chain in this regard. The Rotel RA-12 is particularly revealing across the midrange, as we discovered when we played Priscilla White’s just-released ‘Very Best Of…’ CD to find her voice a tad less sophisticated than we recalled (it has a great version of ‘Alfie’, but Agnetha’s our new chanteuse for ‘If I Thought You’d Ever Change Your Mind’).
We definitely preferred our digital files decoded by the coaxial inputs on the rear panel over both the optical inputs (by a slight margin) and the front-panel USB (by a large margin),
but we wouldn’t rule out the front USB for ‘quick listens’. Although we’re kind of died-in-the-wool standalone DAC kind of guys here at Best Buys, the performance of the RA-12 with digital sources was good enough to be tempting… very tempting. If only it offered a choice of filters, we thought… but at the asking price, this would be too much to ask.
True vinyl lovers won’t be tempted to ditch their head amps by the phono stage in the RA-12, but it’s very serviceable. If you’re running a rotating rig that runs less than a grand, you’ll be well-pleased with its performance. Speaking of which, we gave the RA-12 a bit of a caning in the listening sessions, during which it got a tad warm, so make sure that (unlike us) you follow the ventilation instructions on the second page of the Owners’ Manual.
Fifty years in the hi-fi biz and Rotel is still going strong, and with the RA-12 once again proves it can build an amplifier that’s not only richly endowed with features, and is more powerful than you might guess from the specs, but also sounds excellent… and despite all this, it’s managed to keep the RRP in three figures. Highly recommended.
Rotel RA-12 stereo amplifier
FOR: Lovely design, Clean interface, Full-featured
AGAINST: Old-school remote, Automatic stand-by, Speaker terminals
Inputs: 60W per channel
IMD: < 0.03%
Frequency response: 10Hz–100kHz (±1dB)
Phono response: 20Hz–15kHz ±0.3dB
Damping factor: 180
Phono sens/Imp: 2.5mV/47kohm
Line sens/Imp: 150mV/24kohm
Input overload: 180mV/5V (Phono/Line)
Tone action: ±10dB (at 100Hz & 10kHz)
S/N ratio (IHF-A): 80dB/100dB phono/line
Power consumption: 300W
Dimensions (whd): 430×92×342mm
Warranty: Three Years
Contact: International Dynamics Pty Ltd
03 9426 3600