The SIA-025 is a Class A integrated amplifier, offering 25 watts per channel, weighing in at a hernia inducing 42kg it’s a serious proposition.

From a sonic perspective I’d put this amplifier up against pretty much anything at any price point. Sure, someone may prefer the tone of tubes or a more clinical up front presentation, that’s purely subjective at the end of the day. But if you crave that emotional connection, to be drawn in and become lost in the music the SIA-025 beats them all.

It may ‘only’ offer 25 watts per side, but remember that this is 25 watts of pure Class A, the mains transformer is 1.4kVa so you get a vice like grip that will control difficult speakers with absolute ease. If you have speakers with big bass drivers that can move a lot of air the SIA-025 utterly transforms their performance, you think you know what your speakers are capable of, think again!

You can also switch it in Class AB mode if so desired, in this mode power output rises to 100 watts per channel so if you require even more drive, power and fireworks it’s there, the tone changes in AB mode but it still offers stunning performance.

With 3 pairs of XLR inputs and 2 pair of RCA inputs there are enough connections to satisfy pretty much anyone, you can adjust input sensitivity for every input as well. There are XLR Pre-outs and the speaker terminals will happily accept either 4mm plugs or preferably spades.

Surely an integrated amplifier is a compromise over a pre/power?

On the face of it you’d think so, dedicated power supplies in separate boxes, more efficient, each box has less to do etc. The SIA-025 was designed with the absolute ultimate performance in mind. The amount they have managed to pack into the relatively compact chassis (it’s quite a bit smaller than an RI-101!) is nothing short of phenomenal. Build quality is exactly what you’d expect, simple, elegant and functional, from an engineering aspect I’d put it against anything, at any level.

In reality the SIA-025 gives nothing away to a pre-power combination, even one costing significantly more than the £21000 asking price here. The SIA could be a lot more expensive and it would still hugely punch above its price point and stature as an integrated amplifier.

How does it sound?

It’s one of the very best amplifiers I’ve ever had the pleasure of listening to. It is perfectly natural with superb dynamics and incredible realism. The large mains transformer ensures it never runs out of steam and can cope with huge dynamic shifts in the music with absolute ease. The level of finer detail, expression and emotion it can pull out of a recording you know intimately well is scary.

If you want your system to simply disappear leaving you with the closest representation of a live musical performance the SIA delivers massively. It creates so much scale and presence in the room and paints a genuinely holographic soundstage that is as deep as it is wide.

In my experience most people I visit and most systems I see for the first time are ones where the amplification is not up to the job of driving/controlling the speakers adequately. Slow, ponderous bass which overwhelms the whole presentation is a common theme; as is a system which sounds exciting to listen to for about half an hour, but then becomes strident and fatiguing and almost contrived in nature.  Get the amplifier and system right and you end up with a sound which allows you to really connect with the music. The SIA-025 is at the top of a very short list of amplifiers which almost remove themselves from the system and simply get on with the job of playing music.

How does it compare to an RI-101?

It absolutely sounds like the bigger wiser brother of the Reference Integrated. In my mind the RI-101 is the absolute bargain of the century in terms of a high-end one box amplifier. The RI-101 is a little more neutral in presentation terms but the SIA-025 just does something magical that draws you in, in reality it sounds totally effortless in comparison. It offers far greater levels of fluidity, emotion, detail and gets you even closer the music. If the rest of the system is at the appropriate level and you compare the 2 amplifiers together it won’t take very long for you to realise how much of a game-changer the SIA is. An amplifier for life is an apt description perhaps!

Value for money

When you look at some of the other amplifiers (be it one-box or pre-powers) that exist in the marketplace today I would even go as far to say that the SIA-025 offers brilliant value for money. You could spend a lot more money on an esoteric pre-power from other brands and end up with a musically less rewarding sound.

To ensure the ultimate performance is obtained from the SIA-025 there are several things you can do to extract every last possible drop of performance.  Stillpoints will ensure that whatever the amplifier is sitting on has absolutely no influence on the sound being produced. Put it on glass or a wooden shelf and sonically any amplifier will change. At this level we want no compromise in performance. Also connecting the amplifier to an Entreq ground box will lower the amplifiers noise floor, so the level of micro-detail, expression and emotion will increase.

The same applies with mains power as well, add a good power cable from Shunyata Research and you’ll unlock even more from the SIA-025.

Of course all of these items can be added in time as and when funds permit. Half the fun is trying them out and hearing your system pull ahead even further!

More Reading

Vitus SIA-025 Datasheet

Hi-Fi+ Magazine Review (Chris Thomas)

Part Time Audiophile