Topping Audio

B100 Monoblock Power Amplifier

£299 RRP

Monoblock power amplifiers are something of a niche product. More often than not, they come in large and imposing cases with menacing-looking heatsinks or an array of valves that could comfortably heat your listening room. Topping's B100 is a different beast entirely – measuring just 44x200x147mm [HxWxD], it is barely bigger than a wireless router.

Unlike the company's similarly dinky PA7 Plus stereo power amplifier I previously reviewed, this is not a Class D design, as you might assume. Rather, it's a Class B amplifier capable of delivering 100W into 4 ohm speakers (70W into 8 ohm), according to the published specs. That's pretty impressive from an amplifier with such a small footprint, but you will, of course, need two for stereo reproduction.

Even more remarkable is the B100's almost invisibly low distortion figures, with THD (total harmonic distortion) quoted as less than 0.00007% at 4 ohms 5W. This is largely due to the technology the amp employs, with Topping's T'ang-ku-la module using a newly developed three-stage feedback circuit. It's designed to reduce both circuit noise and high-frequency distortion, resulting in a spectacular dynamic range of a whopping 151dB.

For perspective, my ancient Leak TL12 plus monoblock valve power amp would struggle to achieve half of that performance with its 14W output. The tech also works to dramatically decrease heat produced by the circuit, which in turn diminishes thermal noise. In use, the amp runs warm but not hot, so while there's no need for industrial heatsinks, the unit is vented on both sides. Three gain settings are offered – Low, Medium and High – with around 10 and 20dB of gain boost, respectively, at the M and H settings. In practice, the M setting provides adequate power for my insensitive BBC LS3/5a speakers and more than enough for my easy-to-drive Tannoys.

Rear panel connections cater for XLR, balanced TRS and RCA cables for pairing with a preamp, such as Topping's E70, which is a perfect partner for the B100s but not supplied for this review (We have, however, reviewed the E50). A 12V trigger input interface is included so that a pair of B100s and a suitably equipped preamp may be powered on and off simultaneously; an external AC to DC power adapter is supplied.

The front panel is minimalist in the extreme, with no mechanical knobs or switches to be seen. To the left of the panel is a touch-sensitive button that powers up the amp(s). It requires a brief press, so don't just hold your finger there and wait for something to happen. A protection circuit is incorporated into the design, which prevents the amp from clipping and causing damage. Build quality is excellent; the unit sports a solid aluminium chassis, and the speaker terminals are robust, accepting cables terminated with banana plugs, spades or bare wire.

THE LISTENING

This amplifier sounds accurate and quite pristine. In a way, it could be described as characterless, as it doesn't demonstrate an obvious tone. It is neither bright nor warm sounding, and there's not a hint of romanticism – it remains truthful and transparent to the incoming signal. Not only does it deliver the music faithfully, but it also reveals the true character of source components and the preamp controlling it. For example, spinning vinyl via my Icon PS1 phono preamp (with volume control), I can clearly hear the warm yet shimmering character of the valve stage in contrast with the more sterile sound of streaming through a passive box.

The B100 delivers great instrumental separation and skillfully outlines individual elements of a recording. Elvis Costello's (I Don't Want To) Go To Chelsea is a sparse and angular piece of new wave pop, and through the B100 monoblocks the scattergun drums and spongy bass line are laid bare, allowing the gnarly guitar and snotty vocals to push out of the mix. While this type of presentation can sound stark compared to more euphonic-sounding amplifiers, it reproduces music truthfully without any artificial sweetening.

More modern pop recordings are often sweetened enough though, as I find with my favourite female pop duo ARXX. As much as I love their perfect pop anthem, Call Me Crazy, it's chock-full of digital production techniques and artificial ambience that can come across as dense and murky. Yet the B100s cut through the crud more powerfully than my old thermionic monoblocks. For the first time, I can hear the space between the layers, which opens out the recording to reveal hidden depths previously unheard.

THE VERDICT

Topping's B100 monoblock power amplifier is a remarkable bit of kit for the money. For under £600, you can have a clean, smooth and neutral solid-state stereo powerhouse that punches way beyond its price point. Depth and detail is in abundance through this little amp, and its power belies its size. For clean, transparent amplification that won't break the bank, look no further.

Visit Topping Audio for more information