Интегральные усилители — Boulder 866

The 866 is a stereo Class AB integrated amplifier from Boulder Amplifiers of Colorado and the successor to the 865. Compared with the older model, Boulder lists higher power, more efficient manufacturing, lower weight and higher current output. It is offered in two versions - an all-analogue model for traditional systems and an analogue plus digital model with a streaming DAC for listeners who play files and network sources.

Key specs that matter

Continuous output is 200 W per channel into 8 ohm and 400 W into 4 ohm, with peak figures of 250 W into 8 ohm, 400 W into 4 ohm and 700 W into 2 ohm. There are three pairs of balanced 3-pin XLR inputs at 100 kohm, and maximum analogue gain is 40.4 dB. THD is 0.01%, and equivalent input noise at 20 kHz is 2 microvolts. Frequency response is 0.00/-0.04 dB from 20 Hz to 20 kHz, with -3 dB points at 0.015 Hz and 150 kHz. The case is 440 mm wide, 390 mm deep and 190 mm high, and it weighs 24.5 kg. Mains options are 100, 120 or 240 V at 50-60 Hz, and maximum consumption is 1000 W.

Engineering and use context

On the digital version, the input panel adds Ethernet, four USB ports, AES3 that can be adapted to S/PDIF, Toslink and Wi-Fi, and the converter accepts PCM up to 32 bit/384 kHz and DSD up to DSD128. This converter stage, with its own DSP filter, later became the template for the digital section of Boulder's smaller 812 DAC preamplifier, a separate box. Speaker cables attach to 6 mm thumbscrew binding posts. A full-colour touchscreen on the front handles input selection and setup, while the Boulder app allows custom configuration and naming of sources. An RF remote is available as an option. As with other Boulder products, manufacturing and quality assurance take place in house.

Pairing

Boulder states that the rated power holds into any loudspeaker load, and the rising output into lower impedances leaves headroom for low-impedance or low-sensitivity speakers. Because every analogue input is balanced, sources with XLR outputs connect directly, and Boulder's 812 DAC preamplifier or its phono stages such as the 508 are natural partners. Buyers who stream can choose the digital version and use the internal DAC instead of an external converter.

Alternatives

Boulder lists no other integrated amplifier, so the 866 has no same-brand counterpart in its category.