Super Test Stereo Amplifiers – Sonic Boon (Part 4) : Pioneer A-70, Rotel RA-12

Pioneer A-70

Class-D amplification

Contrary to popular belief, the ‘D’ doesn’t stand for ‘digital’. This type of amp circuit runs cooler and more efficiently than class-A or -B amps, and is becoming far more prevalent in hi-fi kit due to its eco-cred.

The Pioneer A-70 is the company’s high-end stereo amp – a Class D model and sits atop of the new range of five with a fittingly impressive feature set.

Before you’ve even turned it on, the A-70 makes a memorable impression. It’s considerably bigger than the other amps here, not to mention much heavier, weighing in at a touch over 17kg.

Pioneer A-70

While you might need a hand to lug it out of the box, it’s a small price to pay for such a solid, quality finish; the whole chassis is made from aluminum panels.

The front of the A-70 looks equally well-made, if rather busy, with dials and buttons that match an equally busy remote. The five dials control input selection, volume, bass, treble and balance, and there are buttons for selecting between speaker setups, a ‘loudness’ button for added punch to low-volume playback and a ‘direct’ button for bypassing the tonal controls.

There’s even a button for switching the phonon stage between the moving magnet and moving coil inputs, unusual at this grade and a USP for the A-70 in this test, adding another string to its already well-equipped bow.

It does only have three line level inputs, which is a little on the light side, but goes someway to making up for that with a built-in DAC, complete with coaxial and USB inputs that will accept high-res files up to 24-bit/192kHz. RCA sockets allow the A-70 to be used as a power amp for your home cinema, too.

There’s even a button for switching the phonon stage between the moving magnet and moving coil inputs, unusual at this grade and a USP for the A-70 in this test, adding another string to its already well-equipped bow

With an impressive 90W per channel, the A-70 serves up a powerful sound. The bass has a kick that leaves some rivals sounding positively thin. It’s an exceptionally open sound too

Power and detail in abundance

Turn on the A-70 and its size translates into a similarly powerful performance, with an impressive stated 90W per channel. The bass is taut and suitably punchy, with a real kick that leaves amps such as the Onix and Rotel RA-12 sounding positively thin in comparison.

It’s an exceptionally open sound too, and a play through of Vivaldi’s Four Seasons (Winter) shows off the pure level of detail the A-70 is capable of offering. Press the ‘direct’ button and it goes up a notch, tightening up the sound and widening the soundstage even more.

There’s no shortage of power here, but complexity makes things unravel a little

However, this piece of music also shows up the A-70’s weaknesses. While the solo violin is relayed with admirable clarity, once things get more complex, the A-70 seems to lose its way.

It lacks a sense of momentum and rhythm which means it can sound rather messy, throwing everything slightly off tempo and skipping over more subtle elements of the track. Unfortunately, we found this to be a trait that reappeared across the amp’s digital inputs too.

Overall, the A-70 is certainly a well put-together bit of kit with a generous spec list, albeit towards the top end of our price range. If you’re looking for a clear and powerful sound, you’ll find it in abundance here – but it’s the A-70’s rhythmic shortcomings that cause it to fall just short of greatness.

Class-D amplification

Contrary to popular belief, the ‘D’ doesn’t stand for ‘digital’. This type of amp circuit runs cooler and more efficiently than class-A or –B amps, and is becoming far more prevalent in hi-fi kit due to its eco-cred

Rating: 4/5

For: Strong build quality; lots of features; powerful sound; great clarity

Against: Lacks a sense of momentum and subtlety when music gets busy

Verdict: A well-featured, powerful amp, but not the last word in timing or dynamic finesse

Pioneer A-70 specs

  • Type: Integrated
  • Power: 90W
  • Tuner: No
  • Inputs: Line level x 3
  • Outputs: Preamp, speakers, headphones
  • Phonon stage: Moving magnet, moving coil
  • Tape Loops: 1
  • Tone Controls: Yes
  • Remote Control: Yes
  • Finishes: 2
  • Dimensions (H x W x D): 14 x 43.5 x 36cm

Rotel RA-12

With its Award-winning sibling the RA-10 sitting pretty beneath it, the Rotel RA-12 was always under pressure.

On paper, the differences between the two are clear. The RA-12 has an increased 60W per channel (up from the RA-10’s 40W), a built-in DAC worth $269 if bought separately and the possibility of Bluetooth connectivity. It’s bigger too, and nicely built with an added display and more buttons in place of the RA-10’s perhaps nicer-looking dials.

Rotel RA-12

On the back you’ll find five line-level inputs (including moving-magnet phonon), four digital inputs (two optical and two coaxial sockets), two sets of speaker outputs and preamp outs.

As with the Pioneer A-70 (previous), Rotel has provided a built-in DAC (it can handle files up to 16-bit-48kHz) – and at this price, its inclusion is to the company’s credit.

It also goes some way to make up for the lack of FLAC or Apple Lossless support via the front USB port (it only accepts WMAs up to 16-bit/48kHZ, as well as AAC, MP3 and WAV, although you can plug in a Bluetooth dongle too…)

Before we start getting into the nitty-gritty of what RA-12 sounds like, it’s worth remembering that it’s the cheaper amp here, and one of the best featured too – even compared with the pricier amps.

Following the act of its Award-winning little brother, the RA-10, was always going to be tough and while the RA-12 puts in a commendable performance, it falls just short of those heights

A stable performance

Belting out Lady Gaga’s Paparazzi, the RA-12 shows it shares a similar tonal balance to its sibling, offering an even presentation from top to bottom.

The midrange is particularly articulate but the bass could pack a little more punch for our tastes. Without it, we found the amp was in danger of sounding a little restrained when it came to playing livelier tracks.

We also found the RA-12 moved less subtly between the quiet and loud sections of music compared with pricier amps such as the Naim Nait 5i.

Packed with features – including optional Bluetooth – the RA-12 is well worth a listen

However, while it might fall behind in dynamic thrust, there’s a decent amount of detail here, especially when you consider that it’s nearly $538 cheaper than Naim’s offering in this test.

It’s also got some real power behind it, and stays composed even at higher volumes, offering a strong and stable performance throughout.

Switch to the digital inputs and we found the sound to be largely consistent, if slightly brighter, adding some welcome sparkle to the top end.

Overall, the Rotel RA-12 is a good, competent amp. It does just enough to keep you listening, but lacks that little something extra to take it from being simply good to something really special.

But while it doesn’t offer the best sound in our test, its feature list falls massively in its favor, and will no doubt prove appealing for those looking for a solid, well-featured stereo amp.

Overall, the Rotel RA-12 is a good, competent amp

Wireless is more

Rotel’s inclusion of a USB socket and provision for its own Bluetooth dongle (which comes with the amplifier) opens up the RA-12 for use with smartphones and tablets – a remarkably forward thinking step.

Rating: 4/5

For: Well-balanced sound; good control; decent detail; well featured

Against: Lacks subtlety and panache

Verdict: A well-priced, well-balanced and well-featured amp that just falls short when it comes to expression

Rotel RA-12 specs

  • Type: Integrated
  • Power: 60W
  • Tuner: No
  • Inputs: Line level x 4, USB
  • Outputs: Preamp, speakers, headphones
  • Phonon stage: Moving magnet
  • Tape Loops: 1
  • Tone Controls: Yes
  • Remote Control: Yes
  • Finishes: 2
  • Dimensions (H x W x D): 14 x 43.5 x 36cm