Yamaha DSP-A1
Surround Amplifier

This DTS trailblazer is The Full Monty

Yamaha DSP-A1

Yamaha has rewritten the AV rule book. Bob Tomalski is awestruck by the DTS/Dolby Digital DSP-A1

Yamaha's A1 product code is totally apt. In home cinema terms we're talking of a flagship amplifier that leaves no feature unfulfilled. Twenty-three kilos of solid steel casing, heatsinks and transformer. Fist-sized control knobs and a dialogue-packed display. More sockets than a telephone exchange. No matter how you look at it, this beast just begs to be bought.

Forget the looks, drool over the spec. The DSP-A1 offers not only Dolby Digital but DTS cinema sound decoding, thanks to Yamaha YSS249 and Motorola 56009 processor chips.

The A1 even has direct inputs for a further decoder (MPEG Surround perchance?) plus a swathe of optical/coax-ial terminals for today's digital age. It has 40 DSP modes and (best of all) packs a healthy 110W punch on the five main channels plus 2 x 35W on front effects for Yamaha's proprietary Cinema DSP seven-channel mode.

Like the cat who'd found the cream, I heaved this monster into my lounge (almost suffering a hernia in the process) and put it to work, using a Panasonic DVD-A100 player and Videotec-modified Pioneer CLD-925 laser disc player, coupled to KEF's excellent new THX Reference speaker package.

A week later I dragged it into our lab (another hernia) and coupled it to our test gear. This is what I found...

Knobs, Terminals and Trivia

Have you ever lifted an amp weighing 23kg on to a shelf? Don't even try. With this box we're talking bulk that could seriously damage your health (not to mention shelving).

At 435(w) x 190(h) x 473(d)mm it's best suited to a solid hi-fi rack, equipment table or other dedicated support. When installing, leave plenty space to get at the terminals. You'll soon see why.

The front panel is typical Yamaha; satin black and uncluttered. Two knobs provide volume and input selection. There's also a tape monitor. Under a flap you'll find menu, program and effects buttons plus rotary controls for bass, treble, balance and the recording output. A convenience input (S-Video, composite and stereo audio) is also fitted for quick hook-ups.

Now peer round the back. Over 50 phono sockets are there to confound you plus S-Video, plus TOSlink, plus binding posts, plus a mains outlet. This leads to serious spaghetti, hence my caveat about leaving plenty of space for manoeuvering and manipulating the cables.

First up are the regular AV inputs. You have provision for two play-only sources (marked LD and TV/DBS) and three rec/play sources (VCR 1-3). With the front panel input this makes six, all with composite and S-Video support.

One point to note. Video 3 can be switched as a regular rec/play port or configured as a second monitor out. In this mode, the input becomes play-only and is recommended for DVD.

Then there are the audio-only inputs. You have a total of three play-only ones (phono, tuner and CD) plus two rec/play for taping.

For digital sources there are coaxial terminals for CD, TV/DBS and DVD/ VCR3. Optical TOSlinks are fitted for CD, DVD, TV/DBS and LD, plus a rec/ play loop for mini disc/DAT/CD-R recording. For laser disc Dolby Digital replay there's an RF input which routes the baseband signal through the onboard demodulator.

Now the outputs. In true Yamaha style there are eight speaker terminals (left, centre x 2, right, front effects x 2 and rear effects x 2) plus preamp outputs for all channels. You also have coupler links allowing the internal power amps to be disconnected and external amps used. Even better, there are mono and split subwoofer outputs for better distribution of the bass to a pair of subwoofers.

The speaker outputs are adequate for large cable providing it's stripped bare. Sadly the binding posts do not accept 4mm plugs, but here's a Tomalski top tip: You can purchase flexible 'pigtail' converters from Custom Cable Service (0181-942 9124) at £5 per pair which make installation a doddle. You get less 'bunching' of the chunky cable at the back of the amp and no risk of copper strands shorting across the terminals.

Last (but not least) there's a switched IEC mains outlet which is useful for powering a DVD or LD player. Whenever the A1 enters standby, power to this outlet is cut.

Macho menus

There are 12 functions in the menu mode, most of which set the system for level, bass management or channel tonality. First up is the speaker mode.

Icons on screen indicate large/small options for main and surround and large/small/none for centre. You can also set whether LFE (low frequency effects) are handled only by your subwoofer(s) or the sub and main speakers.

For Dolby Digital and DTS soundtracks you can ensure that their extra-deep bass doesn't destroy your woofers. An attenuator (ranging from -20dB to 0dB) can be used to set the maximum output of the LFE to the sub or the sub/main speakers.

Not sure about all this bass management? Use the LF Test function to check how bass-happy your centre/surrounds actually are. It outputs a low frequency test tone (rumble is a better description) that can be set from 35Hz to 250Hz and switched from channel to channel and the subwoofer. By using this tone you can gauge whether it's best to direct low-bass to the surround/centre speakers or the subwoofer.

Front mix is another setting. Choose Yamaha's unique seven-channel mode (where DSP provides front ambience through additional speakers) or regular five-channel.

As with the previous amp from Yamaha, the DSP-A3090, there's a -10dB main speaker option which ducks the left and right levels, allowing the centre and surround to be better balanced. This function is only useful should the centre or rear boxes be hugely insensitive. Remember, with 110W per channel you have plenty of oomph at your disposal.

Late night listening to Dolby Digital can be an over-dramatic experience - especially if you crank up the volume to hear dialogue then suffer explosive LFE or surround.

As with all Dolby Digital amps the A1 has dynamic range reduction, but unlike competitors you can set the degree of compression manually. There's high-level cut and low-level boost, plus max, standard and min presets. Shame this lot doesn't work with DTS, the other 5.1 sound format.

An ideally balanced home theatre system will probably have same-brand speakers throughout. Yet in the real world, people often have a mixture of models especially prior to upgrading. Yamaha has a panacea for this. There's a five-band graphic equaliser that can be applied to the centre channel and a parametric equaliser for all channels.

With the latter you select the frequency for boost or cut then wind up the wick for best effect. A high shelving equaliser is also available for finely tuning the upper turnover level. By careful tweaking you can make different speakers sound more similar (although it has to be said this is no replacement for buying a properly balanced speaker system).

You have tweaks that set the inputs at switch-on. The TV/DBS and DVD terminals can auto default to a specific audio source or memorise the last set. There's also a memory lock and an 'initialise' feature for resetting the DSP to factory defaults. And perchance the front panel display proves a tad too distracting, a dimmer can reduce or totally switch off the glow.

One feature you might expect on the menu is channel calibration. Yet it's missing, because (most sensibly) it has a dedicated switch on the remote handset. A 'rocker pad' selects the channel to be adjusted (rock it up/down) and volume (side-to-side).

DSP COOL OR OVERKILL?

First of all, decide which surround mode you want to use. If you have a laser disc player and a clutch of DTS titles then there's no debate. Select DTS decoding and enjoy this full bandwidth 20-bit technology in all its digital cinema sound glory.

Or maybe you have Dolby Digital titles? Perhaps a few NTSC laser discs, or some DVDs? Just engage the digital input and the Al will detect and decode the data, giving a read-out of which channels are active.

Or Pro-Logic from an analogue source? Again, the decoding is there at the press of a button.

Trouble is, the choices aren't obvious. As well as regular DTS, Dolby Digital or Pro-Logic, there's Yamaha's 'Enhanced' version of each, plus SciFi, Adventure and General DSP settings. You'll find these add extra reverberation and rear channel delay to emphasise the spaciousness of surround. Whether it's what the director intended is another matter.

As for DSP to enhance audio-only sources, the A1 runs riot to the tune of 18 additional modes designed specifically for music. If you don't like them you can trim the DSP parameters using the onscreen menus.

So what about those features made for selling rather than using? The A1 sports a sleep timer and a high-tech handset. You also have a bass booster, but believe me, it's totally unnecessary.

The silver handset's cover folds back on itself giving full access to over 50 buttons, or you can operate the 'basics' with the cover closed. Key features include IR 'learning', an illuminated keypad and multi macro operation, which fires commands sequentially, thereby controlling several AV components at once.

CHAMPION PERFORMANCE

Staggering, stunning, startling. All these superlatives describe the A1. I'm talking about a monster amplifier with mammoth performance. If ever there were an argument for bass-rich' surrounds, this is it. The A1 in DTS mode really does bring the cinematic experience to your home. Everything is rendered larger than life. The DTS laser disc of Jurassic Park brought galloping gallimimus thundering through my lounge. The separation is amazing. I felt trapped in the stampede with the beasts bursting up front, then barging behind and around my settee.

Finally you hear the footfalls of the chasing T-Rex, then much gurgling at centre moving to rear right as the toothy dino satisfies its lunchtime blood-lust. Ripping flesh. Yuk. Can an amplifier sound that realistic? With DTS it surely can.

Although I consider DTS the pinnacle of current cinema sound, Dolby Digital isn't put in the shade. From DVD I played Anaconda. The waterfall sequence (chapter 26) is one of the best examples of atmospherics I have heard from a jungle-scene movie. There's snake crushing at centre, a waterfall splashing to left and right and eerie forest noises all around.

Try listening to just one channel and you'll realise what 'discrete' actually means. We're talking effects that are totally unsullied by inter-channel interference.

Another DVD I like to use for test is Mars Attacks. The aliens landing sequence is great for picking out detail: trouser flapping bass during the shoot-em-up; warm, rich music during the establishing shots and precise ack ack at centre.

Is there anything I didn't like? Well no, not really. If I had an alien blaster put to my head and was ordered to nitpick, I'd blurt that the front-to-back separation when switched to a Pro-Logic analogue source is not quite perfect, with the merest hint of centre-to-rear bleed. Perversely, the enhanced mode (which in theory should worsen separation) cleared it up.

And what of the DSP? Are the effects worth having, or is this Yama-ha's way of bumping up the price?

My answer: Yes, they are worth having and no, you are not paying unduly for them as they are all part of the processing that delivers the Dolby decoding.

I preferred the extra ambience delivered by the soundfield processor. I also loved the graphic equaliser possibilities at centre. You can trim some treble off 'screechy' soundtracks (and lacklustre centre speakers) making their presentation more palatable. How strange though that Yamaha hasn't used its DSP expertise to offer THX-type decorrelation to improve Pro-Logic sources. This would seem the amp's only missed trick.

THE SOUND OF MUSIC

On music I can report the Al is neutral. Not bright, nor stodgy. In fact it's difficult to hear any 'signature' added at all. Used with a Meridian 500 CD transport, the soundstage is totally convincing. Shut your eyes and you could be in the concert hall and that's with the DSP defeated. Played via the Panasonic A100 DVD machine it sounded sharper more clinical, yet not 'tinny'. What you put in you get out.

In summary, the Yamaha DSP-A1 sets a new standard for price and performance for high-end home cinema amplifiers. It delivers superb audio, is packed with highly useful features and is easy to use.

In terms of competition, it's pretty well out on its own. My bet is that Denon will be watching this muscle amp very carefully. Although it lacks THX, the DSP-A1 matches Denon's AVC-Al pretty much channel for channel in sonic terms, offers DTS decoding and is E900 cheaper. With what you'd save, you could buy a DVD deck, a suitcase of Region One discs and even a weekend in New York to buy them.

And remember, if you crave THX-style re-equalisation and active sub crossovers, you can, in effect have them thanks to Yamaha's parametric eq and bass management.

Best of all, The DSP-A1 is future proof. The direct six-channel inputs can be used for MPEG Surround or whatever other technology might be thrown at it.

Full Monty macho cinema? Too right. The DSP-A1 is a worthy successor to the classic Yamaha DSP-A3090. Get a demo and take along your credit card.

It's a bargain. I guarantee you'll be impressed.