Preamplifiers — Boulder 3010

The 3010 is the preamplifier of Boulder Amplifiers' 3000 Series, the range that also includes the 3050 mono and 3060 stereo power amplifiers. It uses four chassis sections - one for the display, controls and computer supervision, two more for the gain and output circuits of each channel, and a separate 3000 power supply housing four independent supplies for the left analogue, right analogue, supervision and user interface, and standby sections. Boulder quotes a noise floor of -102 dB and channel crosstalk of -135 dB for this layout.

Key specs that matter

There are six balanced XLR inputs, three dual balanced XLR outputs and one auxiliary balanced XLR output whose path has -1 dB of gain. Maximum voltage gain is 20 dB. Input impedance is 333 kohm balanced and output impedance 100 ohm balanced. The unit accepts up to 7 Vrms at its inputs and delivers up to 28 Vrms. THD+N at 2 V output measures 0.0008% from 20 Hz to 5 kHz and 0.001% at 20 kHz, and the response is within +0.00 and -0.03 dB from 20 Hz to 5 kHz, with -3 dB points at 0.02 Hz and 300 kHz. The main chassis is 483 mm wide, 457 mm deep and 235 mm tall and weighs 35.4 kg, while the supply chassis shares the width and depth at 130 mm tall and 20.4 kg.

Engineering and use context

A fully balanced volume control reduces distortion and step noise, spans 100 dB and can be set to 0.1, 0.5 or 1.0 dB increments, with precision of 0.01 dB. Gain can be trimmed independently and in real time for every input and output. Seven front-panel knobs cover input trim, balance, blend for merging the left and right channels, volume and the level of each of the three balanced outputs. Source name, volume, trims and any change in balance or polarity appear on a 37.8 cm colour LCD. Gain comes from the 993SD, a stage used only in the 3010 that combines two gain stages in one machined, resin-potted housing with improved thermal tracking and a new grounding scheme. The supply transformers are potted and enclosed in riveted steel, with a DC blocking circuit. Programmable Theater Mode and a Soft mode are included, and an Ethernet port provides network connectivity with OpenHome compatibility. The supply accepts 90 to 120 V or 200 to 240 V at 50 to 60 Hz, and maximum consumption is 240 W.

Pairing

All audio connections are balanced XLR, so sources and amplifiers need matching balanced sockets. Within Boulder's own range the 3060 stereo amplifier or a pair of 3050 monoblocks are the matching 3000 Series power stages, and the extra outputs make it possible to feed more than one amplifier for bi-amplified speakers.

Alternatives

Boulder's 2110 is the preamplifier of the 2100 Series, which uses the 993S gain stage.