The A-S700 still sports bass and treble controls. Many audiophiles don’t favour these because when you use them, some distortion is inevitable, but my view is that if you need to add a little treble lift to compensate for an overly-damped room, or roll off some bass because you have no other option but to put your speakers too close to a wall for whatever reason, it’s better to correct the frequency response with tone control and put up with a tiny increase in distortion than to endure an unbalanced frequency response. (Note, however, that I am talking about very small movements of the bass and treble controls away from the midway position. If you have to move either control further than the ‘10’ or ‘2’ o’clock positions you should instead be looking at correcting the underlying issues!)

I was also pleased that the A-S700 also has a balance control. Even if you have your speakers correctly positioned so you get a perfect image at the listening position, this will only be true with well-recorded CDs, and I am always surprised at how many CDs are recorded hotter in one channel than the other, and thereby shift the image too far to the right or left. (I suspect the reason is that many recording studios do not check their monitor speakers’ accuracy as regularly as they should.) And when a recording is not correctly balanced, you will either need to adjust the balance control on your amplifier to ensure correct balance, or move your speakers. I know which I’d prefer to do!

The A-S700 is supplied with a full-function remote control that will operate other Yamaha components as well. However, although the amplifier is supplied in two different finishes (satin black or brushed aluminium), the remote control for both is brushed aluminium.

In Use and Listening Sessions

Setting up the A-S700 is relatively straightforward, but there are some things you do have to remember. The first of these is that if you choose the satin-black finish, you should make sure your hands are absolutely clean before unpacking and positioning the amplifier, because the surface shows fingerprints quite easily, and if you mark it, you will need to apply some elbow-grease to remove them. The second is that for whatever reason, I found the speaker terminals quite difficult to turn (perhaps because of their diameter and the proximity of the protective shrouds). Although they’re good quality terminals, they could have been improved, particularly given the AS700’ s price. Luckily, the terminals will accept standard banana plugs, as well as dual Pomona plugs, so I’d suggest wiring up your speaker cables with either of these fittings rather than using bare wire. Finally, you need to remember to set the speaker impedance switch before you start using the amplifier, and to do so with the amplifier switched OFF! (If you forget, and need to move the switch, you should switch the amplifier off, and then the mains power, before re-setting the switch.)

The volume control had the slightly spongy feel that is typical of motor-driven volume controls, however the benefit is that the control actually rotates when you press the volume ‘up’ and ‘down’ buttons on the remote, so you can always see the volume setting on the front panel. The input source selector has a lovely action under the fingers, thanks to the encoder circuitry, and the LEDs are bright, so you can always see what source you’ve selected from quite a distance away, but I was slightly perplexed that although the action of the control is contiguous, in that you can spin it in either direction without ever reaching an ‘end stop’, the actual switching stops once you have reached the Line 3 input when going anti-clockwise, and the Phono input when going clockwise. This isn’t a problem, it simply means that although it’s an encoder, it works like a mechanical selector. I imagined that perhaps this was deliberate, considering that the styling of the A-S700 echoes the styling of the amplifiers Yamaha was designing ‘way back in the ‘70s.

After experimenting every which way with the Yamaha A-S700’s impedance selector and a variety of different loudspeakers, every one of which I knew the exact impedance of (thanks to graphs of the impedance moduluses, and lists of the actual measured ‘nominal’ overall impedance supplied by Newport Test Labs), I eventually concluded that if you are using just a single pair of speakers with the A-S700, you should set the impedance selector to the ‘high’ position, even if the label on the rear of the speaker says ‘4Ω’. It is only if you have connected TWO pairs of speakers to the A-S700, and will be using the A+B mode regularly that I would recommend using the ‘Low’ position. (I know this is somewhat at odds with Yamaha’s recommendation, but I think Yamaha is playing it super-safe.) As a result of my investigations, all my listening sessions were conducted with the A-S700’s impedance switch set to the ‘High’ position. The A-S700 proved to be very powerful, as it was easily able to over-power even the largest and most inefficient speakers I had available, in the process creating louder sound pressure levels than most people will ever need. The A-S700 is so powerful, in fact, that even with inefficient speakers in a large room I don’t think you’ll ever be hungering after more power than it can deliver. It really is an amazingly powerful amp! Even when you’re not running it full tilt (and you won’t be), the power that is available on tap means that the bass is really solid and well-defined, so that there is a real sense of authority in the lowest frequencies. More importantly, even if there’s a lot going on in the bass region, the power available means that there are no unwanted modulations of the very highest frequencies, so the treble sound is as pure as it is when there’s very little happening down low. But the bass isn’t just big, it’s also so rhythmic and bouncy that you don’t even start to question pace and timing: they’re right there… vibrant and on the go.