Power Amplifier Soulution 511 Stereo Amplifier

Soulution 511 – stereo amplifier with audiophile-grade switched-mode power supply and class A operation

The 511 is a stereo power amplifier that adopts the design principles of the reference series 7 and makes them available in a more compact form. Its foundation is a "switched-mode" power supply optimised for audio applications and consistently shortened signal paths – not only for the music signal, but also for the current paths feeding the amplification stages. The unit operates in three modes – stereo, dual and mono – switchable directly in the device menu, so it can be deployed in a classic stereo setup, in bi-amping or as a monoblock.

The amplification section is derived from the technology of the 711 and 701 models. At its heart is a proprietary voltage amplification stage with linearised amplifiers with a cut-off frequency of up to 80 MHz; current amplification takes place in three stages, each operating within a very narrow and therefore almost linear band. Extensive class A operation is complemented by more than 500,000 µF of storage capacitance in the power supply, which ensures a virtually unlimited impulse response. Current transfer from the amplifier board to the speaker terminals is handled by massive copper bus bars, so that all available power is on hand to drive the loudspeakers.

The power supply comprises a total of ten separate sources optimised for individual functions. The digital and audio circuits are galvanically isolated by optocouplers, so that non-signal electronics cannot affect the music path. Four switched-mode supplies of 4 × 600 VA deliver 2,400 W of supply power, while filtering at both input and output and six linear, fast voltage regulators with extremely low noise provide a substantially more stable supply than conventional transformer-based solutions. Precise quiescent current control maintains the optimum class A operating point under all conditions without additional adjustment, so the sound quality is available immediately after switch-on.

The result of this architecture is a high damping factor (> 10,000 in stereo mode), peak current in excess of 60 A and impulse power exceeding 3,000 W in stereo/dual and 6,000 W in mono mode. In practice this means firm control over the bass drivers, stable imaging of instruments even during demanding dynamic peaks, and a low noise level (108 dB signal-to-noise ratio) that lets the finest details of a recording shine through. Protection circuits monitor RF and DC components at the input, short circuits at the output and the input signal level; in the event of a fault the unit mutes and shuts down automatically. It is controlled by buttons and a rotary control on the front panel, while remote power-up with other Soulution components is handled by the LINK system.

Key features

• Power supply: Four switched-mode supplies of 4 × 600 VA for audio applications
• Storage: More than 500,000 µF of capacitance, peak current above 60 A
• Modes: Switchable stereo, dual and mono operation
• Output: 2 × 150 W/8 Ω, 600 W/8 Ω in mono mode
• Design: Class A, copper bus bars, optocoupler circuit isolation