At the top end of any discussion about high-end audio, there is Boulder. The 2110 preamp is currently the biggest and best preamplifier the company makes, but the new 2160 is about middle of the range, with a pair of mono chassis in the 2000 series, and the “I’ve seen smaller car engines” 3000 stereo and mono chassis above this. Not that the 2160 is in any way a compromise – this stereo chassis weighs a shade under 100kg, is conservatively measured at being able to knock out up to 2.4kW into a two ohm load, and is barely ticking over at 600W into eight ohms.
These are uncompromising amplifiers built to uncompromising specifications, and as such require similarly uncompromising sources and loudspeakers to give their best results. Fortunately, there’s a self-selection process here: no one is going to spend more than £100,000 on amplifier electronics and partner them with an entry level disc player and so-so speakers. As a result, the Boulder designs will have some very fruity upstream and downstream partners; the source to show just how little the Boulder introduces to the signal path, the latter to show what it delivers.
The 2110 preamp is actually four chassis neatly divided into two identical amplifier units, logic, and power supply blocks. From the front, you just see a single control amp, with a separate power supply. Unlike most multi-box designs, the need to physically separate the power supply from the control amp stages is governed more by the load capacities of the shelf than by any potential hum fields: these blocks are designed for immunity from outside influence.
This is a six-input, line-level, balanced only preamplifier – single-ended sources can be used, but will need an adaptor or custom cable. Each one can be allocated a name, has adjustable input gain and trim, polarity adjustment, as well as global adjustments for everything from balance to display level setting. It is also well designed for fault detection and protection outside the signal path, with sensing circuitry that mutes the preamp whenever a problem is detected. There’s an irony here; the one preamp that is least likely to require fault protection has some of the best fault-finding circuitry in the business.
The 2160 is similarly specified. It’s an all-balanced design, with out-of signal path protection for DC offset, clipping, and thermal protection. Any of these conditions trigger the same red LED in place of the normal white LED when operating (if you connect the pre to power using the company’s Boulder Link, these fault conditions can be displayed on the 2110’s front panel). In practical terms, the only time that red LED will glow is if you have a source that is running at greater than 3V of DC offset: in other words, if you have a source component that is either broken, or designed by an incompetent engineer. Less than 3V... the 2160 takes care of the problem. Boulder builds this chassis as a pure linear Class A design, but to prevent a 600W Class A design turning your room into a sauna, the bias current is actively monitored and adjusted (in order to increase efficiency and reduce wasted radiated heat energy) using an high efficiency, microprocessor controlled standby mode reduces power consumption when engaged. And it really does ‘build this chassis’, too: not only are all the surface-mount devices placed and soldered in the Boulder factory, rather than using pressed steel or OEM aluminium parts, the whole casework is CNC milled in-house to extraordinary tolerances. This makes Boulder one of the last true audio electronics ‘manufactories’ in the US.
Building everything in-house even extends to producing custom gain stages. In the 2100 series, this means the new 99H2 modules, which feature surface-mount devices, potted and housed in a milled case. The 2160 sports four of these gain modules.
This is not sheer excess, however. This is amplifier building on a nuclear-bomb-proof scale. Short of actually firing shells at it, it’s hard to think what could cause this to break. Of course, any electronics – especially electronics as sophisticated as this pairing – has components that can and do go wrong, but the amount of protection this amplifier has, you could run it open circuit for days and not trouble the 2160. Not bad for an amp you could weld with! The secret is lodged in Boulder’s history: it made amplifiers for studios in the days when ‘down-time’ was not an option. Amplifiers in such cases needed to be capable of being driven hard for hours on end, with zero failures from one decade to the next. Even modern studios don’t have the same needs for absolute robustness, and people install for price over reliability and even sonics now, which is why Boulder now delivers the goods to the audiophile cognoscenti.
A strange paradox occurs within that audiophile community. We are more likely to know the brand name of an electronic component than its values and tolerances (indeed, if you talk ‘resistor values’ to most audiophiles, they’ll probably be thinking in terms of ‘$’ rather than ‘Ω’). A lot of companies exploit this, and we in the press end up rattling out a list of ‘best’ manufacturer names for resistors and capacitors. Boulder, to its infinite credit, doesn’t play that game; it just uses the right components for the task. Although given it uses a 16A plug and socket as the connector for the 2160 – the kind of industrial-grade connector more usually found in professional lighting rigs – the ‘right components’ are frequently the ones built for the long game. This raises the cost of a product considerably. Take input switching for example: you can do it cheap and expect a dozen years before things start to fail, or do it right for five times as much and know you could switch inputs every second for the next 30 years and not see a failure. “Do it cheap” is not in Boulder’s vocabulary.