It has been a while since Pioneer last made serious two-channel audio components, and it's perhaps a reflection of how crowded things have got in the AV market that it has decided to have another stab at it now.

Unlike some of its rivals, Pioneer does have some pedigree in the two-channel arena; it made some decent CD players and integrated amps in the nineties and a very fine turntable in the seventies. Among the amps was a giant-slayer, the legendary A400, and it's this model that's said to have inspired the new the A-A9.

The A400 was particularly popular with reviewers, because despite being an entry-level amplifier, it worked rather well in higher-end systems.

It delivered in more down-to-earth systems too, and the the rave reviews produced big sales figures for Pioneer. For the A-A9 and its more affordable sibling, the A-A6, the company got hold of an A400 to use as a point of reference at the tuning stage.

This was done at AIR Studios, George Martin's recording facility in Hampstead. Pioneer used this facility for its VSA-AX10 AV behemoth a few years back, and must have a sponsorship arrangement with the place, given how often its engineers seem to visit.

The A-A9 differs quite considerably from the A-A6. The output power is higher for starters - albeit only by 10 watts - and, more importantly, it has toroidal rather than standard mains transformers, aluminium side and front panels, a motorised volume control, MC as well as MM phono input and a USB input (on a B-type socket) for PCs and MP3 players.

There's also a Sound Retriever function designed to improve the sound of such compressed audio sources, and "professional, big, gold-plated, screw-type" speaker terminals (this is perhaps overselling them, but they are rather better than those on the smaller amp).

Volume control

The volume control is a proper motorised Alps potentiometer rather than the continual-rotation type found on the A6, but it only has a small indent to indicate the level. The display shows this numerically, but the amp's 'direct' setting means that the backlight is normally off. In other words, you can't see how loud it will play at a glance.

The sculpted front fascia is attractive and has the minimum of controls, most facilities being accessible via the remote: a very slim affair with the volume buttons a little too close to the off button.

The display, a backlit LCD type, can be dimmed and stays on in standard mode, but in the 'direct' mode, which bypasses the tone and balance controls, it only illuminates when you change level or input, so you can't tell which input is selected without pressing a button.

The A-A9 partners well with Tannoy's Glenair 10 loudspeaker, a model whose openness and dynamics make the most of the amp's precise and subtle sound.

In some respects the Pioneer is a bit too tonally lean for the Tannoy, but it does a fine job of revealing its speed and definition. That said, we tried it after experiencing the smooth Sugden A21aL Series 2, clearly a more relaxed-sounding amp that doesn't have the bold muscularity the Pioneer can produce due to its higher power.

Further listening reveals that the A-A9 is more than able to extract high levels of detail in a transparent and three-dimensional fashion.

A slightly more appropriate comparison is with Cambridge's popular Azur 840A , which costs £150 more and offers another 30 watts. In the studio this translates to significantly greater bass extension and power; we were quite surprised at how much extra grip the 840A managed to deliver.

The A-A9, however, matches it for scale and dynamic thrill power, if not sheer transparency. In some respects it also seems easier to listen to - albeit less emphatic, and a bit more musical, which is interesting.

With ATC's SCM19 loudspeaker, the Pioneer shows it has enough power to do the job even with a less efficient design; the pairing works really well so long as you don't try to play at silly levels.

Ornette Coleman's Change of the Century was delivered in upbeat, timely fashion with the double bass putting in a particularly sprightly performance. Coleman's sax-playing was as lyrical as ever, and when he and Don Cherry played the chorus, the system just let the life in the music flow.

The more contemporary tunesmithing of EST allowed the amp to show it has plenty of bass weight and can deliver a piano with solidity and drive. The midband could possibly have been a hint smoother, and piano notes got a little hard when the volume was pushed, but it's more than likely we were expecting too much in the SPL department - this is still an 85dB-efficient speaker, after all.

That said, the listening continued to be highly entertaining thanks to the A-A9's dynamic capabilities and the way it can place instruments in space with precision.

Bringing in a Rega Mira 3 at the same price produces a relatively pared-down sound, the Pioneer filling in the gaps around the notes rather better thanks to higher detail resolution. The Rega is attractively clean-sounding, but you get the impression it's leaving something out.

We also connected up a MacBook and tried the Sound Retriever function, which seems to increase perceived volume by filling out the sound.

It doesn't appear exactly neutral, but if your MP3s are a little thin it would help, though we'd rather make lossless or higher-bit-rate files. While the subject of alternative sources, hooking up a Funk V turntable with a van den Hul DDT moving-coil cartridge to the A-A9's phono stage reveals some limitations.

Though it delivers a fine sound, it struggles a little with the low output and can't match the dynamics of a standalone stage, and we'd suggest its use be limited to MM cartridges.

Niggles aside, though, the A-A9 constitutes a welcome return to form from Pioneer, offering a good balance of musicality and resolution.

It may not have quite as much charm as the A400, but it's a lot more revealing and better-built, with inputs for sources old and new.