Усилители мощности моно — Boulder 3050

The Boulder 3050 is a single-channel power amplifier and the first product of the Boulder 3000 Series. It was developed in response to demand from owners of the 2050 and was conceived entirely as a monaural design rather than as a mono version of a stereo amplifier. Each unit is built to order and is designed, manufactured and hand-assembled in Louisville, Colorado.

Key specs that matter

Continuous output is 1500 W into 8, 4 or 2 ohms, and peak power is rated at 2100 W into 8 ohms, 3000 W into 4 ohms and 6000 W into 2 ohms. THD at 1500 W into 8 ohms is 0.0005% from 20 Hz to 2 kHz and 0.0035% at 20 kHz, into 4 ohms 0.0008% and 0.0045%, and into 2 ohms 0.0014% and 0.0110%. The -3 dB bandwidth runs from 0.015 Hz to 200 kHz, with the 20 Hz to 20 kHz response inside +0.00 and -0.04 dB. Voltage gain is 26 dB with 1.5 uV of equivalent input noise over a 20 kHz bandwidth. Input impedance is 200 kohm balanced and 100 kohm unbalanced on a 3-pin XLR, and common mode rejection is 90 dB at 60 Hz and 70 dB at 10 kHz. The amplifier weighs 161 kg, its separate base another 39 kg, and the shipping weight is 256 kg.

Engineering and use context

Class A bias is maintained to full rated output by analog circuitry that lifts bias ahead of a transient and then lowers it over 28 seconds. Differentially balanced, instrumentation-style input circuitry feeds two 99H gain stages, a design used only in the 3000 Series, followed by 120 output transistors. Only linear supplies are used. The main brute section with four toroidal transformers, DC-filtered and potted in a proprietary epoxy, serves the input and output sections, and a separate regulated supply powers the supervising microprocessor. Mains enters through a detachable 32 A IEC connector, chosen because the amplifier can draw nearly 30 A peaks, and nominal consumption is 300 W with a 6000 W maximum. The left and right chassis are mirror images that share no metal, the billet metalwork interlocks, and no exterior surface ends at a 90 degree angle. Boards sit in machined aluminum frames over a damping layer.

Pairing

Two sets of 6 mm wingscrew speaker terminals are provided. Boulder Link ties the amplifier to other Boulder components such as the 3010 preamplifier.

Alternatives

Within the 2100 Series, the Boulder 2150 mono amplifier is listed by Boulder at 1000 W into any load in pure Class A.