Mastersound Evolution 845 (Hi-Fi+ 79)

Italian audio has two main thrusts today; gorgeous design and a passion for valves. So it’s perhaps no surprise where Mastersound comes from. The new Evolution 845 integrated amp from the brand comes from Vicenza in north-east Italy.

It’s definitely got the looks. The oversized design with wooden side cheeks, the black transformer cans, the metal top and the exposed valves are extremely elegant and not too dissimilar from Unison Research models (built some 50 miles away), but the elegant stacked heat sink/valve cage of the Mastersound gives it an class of its own.

And it’s certainly got the valves, a quartet of 845 power triodes. Until a couple of decades ago, large valves like the 845 (and 211) were all but forgotten. Their original use (radio transmitter power valves) was long since transistorised and aside from a few interested parties, they would have disappeared into complete obscurity. Fortunately, one of the interested parties was the late Hiroyasu Kondo of Audio Note who in 1988 released the Ongaku, which featured a pair of giant 211 power valves and delivered some 27 of the finest watts (a lot of) money could buy. This opened the floodgates and products featuring large power triodes culled from 1930s radio, cinema and telephony began to appear. Mastersound – beginning in 1994 – is one of the leaders in the field.

There is a school of thought that a valve amplifier is only as good as its transformers. This is simplistic thinking, like saying a camera is only as good as its sensor, but there is more than a ring of truth to the claim. Certainly because the output transformer couples the amplifier circuit to the loudspeaker in conventional single-ended and push-pull valve amp designs, there’s many a good circuit wrecked by inappropriate transformer use. Mastersound doesn’t have that problem, because it designs its own transformers to its own specific specifics. Which leads us to the simplistic test for that simplistic thinking – the heavier the transformers the better. Once again, Mastersound wins out, with some of the beefiest potted transformers around. So heavy in fact, the two output transformers have two smaller power transformers in orbit around the rest of the top plate. Joking aside, this bespeaks of a truly dual mono design, with only the plug, motorised volume and source selector shared between the channels. It also makes that 53kg load very rear-heavy, which can prove interesting if one of the two-man lifting team isn’t aware of the unevenness.

OK, there’s a little confession here; most weighty transformers are heavy because of the amount of metal, but these ones go a little further. Mastersound’s designer precisely specifies the number of windings, demands Litz wire windings, insists on a no-solder policy inside the transformer and then pots the thing inside a can filled with a resin and gravel (no, really… gravel) mix. This not only damps the transformer perfectly, and adds a lot of mass, it acts as a security measure; unscrupulous amp designers trying to find Mastersound’s secrets will destroy the transformer in the process of removing it from its casing; short of calling in Lara Croft and a bomb disposal team, Mastersound’s secrets are safe.

The amplifier itself dispenses with the old-school point-to-point wiring that seems to be the current valve vogue, instead using very serviceable large circuit boards and those 845 tubes sports a pair of ECC82 double-triodes as preamp drivers and a pair of 6SN7GT as drivers in the power amp stage. It has three line inputs and one direct input that by-passes the volume control. All these are single-ended, and the amp features decent gold-plated phonos at the rear. These are joined by four and eight ohm taps for speaker output. There are also biasing controls at the rear of the amp, but Mastersound recommends expert help here. Finally, there’s an under the chassis power switch, a wooden remote that operates volume up and down and nothing else and the whole caboodle sits on four Michell-sized black cones. You’ll need a large table too, because it’s a biggie. Overall fit and finish is very good; just the right balance between bling and understatement for most people.

A zero-feedback, parallel single-ended design featuring a pair of 845s per side is capable of pumping out 55 watts per channel, but the Evolution 845 nevertheless demands an efficient loudspeaker design. A lot of this comes down to the dynamic headroom the amplifier delivers, which means instead of using up the power simply driving a moderately efficient loudspeaker, the Evolution 845 is in its happy place playing at a fair lick while cruising and then delivering huge dynamic swings from its power reserves. A pair of Tannoy Definition DC10T floorstanders fit the bill perfectly (in fact, Mastersound and Tannoy should consider this review something of a matchmaker – the marriage is a very happy one, far better than, say, an Armani kilt or tatties and tagliatelle). I’m sure the usual valve suspects (horns, efficient paper coned speakers, products from Audio Note, Living Voice, Zu, etc, etc) will do just as well.