Усилители мощности моно — Soulution Audio 701 Monoamplifier

The 701 is a monoblock from the Series 7 range from Soulution, the Swiss brand of SPEMOT AG in Dulliken. It replaced the earlier 700 and was built around a switched mode power supply, and Soulution later offered a 701+ upgrade for existing units that adds a new feedback network and a revised thermal design of the gain stages to improve phase response and overload stability.

Key specs that matter

In mono mode the 701 delivers 600 W into 8 ohm, 1,200 W into 4 ohm and 2,000 W into 2 ohm, with impulse power above 12,000 W. Output current is limited at 120 A, maximum output voltage is 70 Vrms and output impedance is 0.001 ohm. Gain is +32 dB. Bandwidth reaches 2 MHz at -3 dB from DC. THD+N at 1 kHz is below 0.0007%, signal-to-noise ratio is 108 dB at 5 W and 1 kHz, and the damping factor exceeds 10,000. There is one balanced XLR input at 2.3 kohm and one RCA input at 4.0 kohm. Idle draw is 180 to 200 W and standby below 0.5 W. The case measures 560 x 306 x 585 mm and weighs about 75 kg.

Engineering and use context

Each 701 contains two amplifier channels. In mono mode they are bridged to reach the full rating, and a rear switch changes the unit to dual mode for bi-amping, where each channel gives 150 W into 8 ohm, 300 W into 4 ohm and 600 W into 2 ohm, gain drops to +26 dB and bandwidth to 1 MHz. The mechanical layout gives both circuits the same thermal conditions and grounding, and Soulution avoids the excessive open loop gain common in transistor designs. Four audio-grade switched mode modules of 600 VA each work with more than 1,000,000 uF of storage capacitance, while the stages that do not handle audio get their own supplies. With no music playing, a control system lowers the quiescent current automatically. Front buttons handle power, mode and input selection. Mode hands turn-on control to a Soulution preamplifier through the LINK system, a 12 V trigger. A balanced loop output relays the incoming signal to a further amplifier, and rear switches set display brightness and start-up behaviour. Output goes to two pairs of gold-plated copper terminals, and versions exist for 220 to 240 V and 100 to 120 V mains.

Pairing

Two 701 units form a stereo pair, and Soulution designed the amplifier for low-efficiency loudspeakers that need very high current. With speakers that have separate bass and treble terminals, one 701 per side in dual mode can feed both sections, and the loop-through output lets a further amplifier share the same source signal.

Alternatives

The Soulution 501 is the monoblock of the brand's Series 5, the line placed below Series 7.