Sony XM-1S Monoblock Amplifier

Slim line mono amplifier with a subsonic filter and bass boost function. Interestingly, both these are specified in a way that indicates a serious slice of power is available. For one, the bass boost is settable only up to ten decibels, rather than the more normal fifteen as the frequency is a very low 40Hz rather than the 45Hz normally applied. Plus, the subsonic filter is no bass sucker but rather a true deep job and is fixed way down at 15Hz. There are two sets of paired connections on the amplifier which means it is easier to connect the speakers up if you are doing multiple woofers. It was tested with a dual 2 Ohm coil Onyx 12S-7 woofer and ran hard at four Ohms rather than showing the amplifier a one Ohm load in parallel. The crossover and gain and bass boost controls are by way of the tops of potentiometers showing through the holes in a neatly lit panel. These do not line up perfectly with the holes but didn’t rub so do not affect function you just have to take care with a screwdriver when making any adjustments as the axis of twist is not concentric with the holes. A separate switch operates the two blue LEDs that shine from the rear drop of the amplifier. All controls and connections are on the front. It is a class D design.
– Class D
– Mono operation
– 1 x 290w RMS @ 4 Ohms, 600w peak
– 1 x 500w RMS @ 2 Ohms, 900w peak
– MOSFET output stage
– MOSFET power supply
– Chromed steel panel top cover plate with four chromed fixings
– 8Ga. fork style power terminals with compression plate connection
– Switchable dual blue LED illumination, white LED lit logo on top panel
– 0 to +10dB Bass Boost @ 40Hz
– High level input
– 2ch RCA input and line out
– Input sensitivity 0.3V to 6.0V
– Switchable subsonic filter @ 15Hz
– Level sensing power switch feature to obviate switching wire use
– Frequency response 5Hz to 300Hz
– Signal to Noise Ratio 90dB
– Low Pass Filter 50Hz to 300Hz
– Fuse Rating 30A x 2
– Mass 2.3Kg
– HxWxD(mm) 43.5 x 223 x 196mm
– C/W Molex high level connector loom
Review by Adam Rayner
A stumpy little spud, I was reminded about getting this out and having a go on it as a direct result of being contacted through the forum’s system by a chap with an MX5 and an under seat woofer. He reckoned he had no space for an amplifier anywhere.
This is one he would be able to hide under a seat. A very small footprint and a dinky little steel jacket make it too pretty to hide though, so I’d find a place in the boot if I were you as the logo lights up in white and then there are two blue LEDs you switch on if you want them, too. The connections are covered over nicely by this chromed steel cover that fixes on with four cross head shortie bolts.
Controls are on the basic side but as described, that 15Hz subsonic filter and the 40Hz depth of the bass boost seemed to indicate that you could drive the bass for real with one of these.
I hooked up the Sony MEX-DV1000 multi disc player and slapped in the new SACD disc I bought on Amazon. Dark Side Of The Moon by old hippies Pink Floyd. It was delicious and you could feel the bass was nicely being reinforced but that was all a bit HiFi and grown up, so I stopped being indulgent (Although I can feel a bad urge for this one disc and the deck becoming the badass Talk Audio Magazine sound quality tester rig piece to be honest) and went and got the old dB Drag disc and that copy of More Bass More Boom More Bottom by ‘Power Supply’.
Now we were cooking. I turned the 15Hz subsonic filter off, I turned up just about everything and delighted as I watched the logo on the front of the Onyx 12S-7’s cone go all three dimensional like those videos on nutter site Realm of Excursion. The bass was full and deep and I was a bit puzzled by the low reading specification of the subwoofer’s efficiency of only 86dB as it was doing a pretty decent job of turning watts into room throbbing bass.
It wasn’t the woofer being more efficient than rated, it was the amp spanking it’s arse.
Perhaps I was being a bit sceptical about how well a small Class D puppy could rock a big twelve in the Acoustic Wood test box and was pleasantly surprised to find it could shift some ruddy breeze. It tracked the nuttier depths and despite the signal from my daft recording being large and so silly deep as to strain a normal power supply, this fully MOSFET amplifier did an incredible job.
Possessed of a quite rare combination of both MOSFET power supply AND output stage, the wee beastie has a heart of a lion and if you are looking for an amplifier that will really offer some proper biff – even to the amazement of your mates when you show them just how small an amplifier it is disturbing their peace, this is worth a look.
The brand is the most famous of all and the amp looks ever so nice with its blue LED lighting and shiny top panel with chrome, which brings an easy resellability to the bod on an upgrade urge. I really was impressed by how much power it put out.
Overall 7.6
Sound Quality 8
Power Output 6
Features 8
Build Quality 7
Value For Money 9