Усилители мощности моно — Boulder 2150

The Boulder 2150 belongs to the 2100 Series of Boulder Amplifiers, and Boulder lists it as the successor to the 2050. It was conceived from the start as a monaural design rather than a bridged derivative of a stereo model, so a stereo system uses two chassis.

Key specs that matter

Continuous output is 1000 W into 8, 4 or 2 ohms. Peak output reaches 2000 W at 4 ohms and 4000 W at 2 ohms. At full rated output the rated THD into 8 ohms is 0.0008% from 20 Hz to 2 kHz and 0.0035% at 20 kHz, into 4 ohms it is 0.0009% and 0.0045%, and into 2 ohms 0.0014% and 0.0090%. The -3 dB points sit at 0.015 Hz and 200 kHz, while between 20 Hz and 20 kHz the magnitude response stays within +0.00 and -0.04 dB. Voltage gain is 26 dB, and noise referred to the input over a 20 kHz bandwidth is 1.5 uV. The 3-pin balanced XLR input has 200 kohm impedance, or 100 kohm when driven unbalanced, and common mode rejection reaches 90 dB at 60 Hz and 70 dB at 10 kHz. Net weight is 99.8 kg, rising to 144.7 kg packed.

Engineering and use context

Biasing remains Class A right up to rated output. An analog circuit monitors output voltage, current draw and load, raises the bias faster than the audio signal when a transient calls for it, then lowers it gradually over 28 seconds. Two 99H2 gain stages, an advance on the discrete 993 module and used only in 2100 Series products, feed 80 bipolar output transistors. The circuit is differentially balanced at inputs and outputs. Surface-mount boards sit in custom-machined frames with individual damping, and dual toroidal transformers are potted inside a welded steel enclosure. All metalwork is interlocking and machined from solid billet, and the left and right chassis are physically identical, which simplifies multi-chassis cinema installations. A supervisor board watches the operating status. Mains versions cover 100, 110 to 120 and 220 to 240 VAC at 50 to 60 Hz, with 250 W nominal and 5000 W maximum consumption.

Pairing

Two sets of 6 mm wingscrew terminals allow bi-wired speaker cabling. Boulder Link passes turn-on and turn-off status between Boulder components, and a 12 V trigger allows remote activation, for example alongside the 2110 preamplifier of the same series.

Alternatives

The Boulder 3050 is the mono power amplifier from the 3000 Series, rated by Boulder at 1500 W continuous into any load.