soulution 525 preamplifier


Uniting source components with power amplifiers, it must perform the critical functions of impedance matching, level balancing and volume control while maintaining perfect signal accuracy and channel integrity. Adding nothing. Taking nothing away.

While the perfect preamplifier continues to be a technical challenge for audio designers, we believe the 525 gets closest to the ideal.

Perfect volume control

The 525 owes much to the design of the range-topping soulution 725 Preamplifier. It uses the same volume control which ingeniously combines the smooth fingertip control of variable resistors with the precision and stability of fixed resistor networks. For the 525 we’ve chosen the best performing Vishay Dale resistors with relays of the utmost quality. The end result is volume control that is finely adjustable in 95 steps of 1 dB each, with no perceptible switching clicks. Truly the best of both worlds.

Advanced Switching

Input selection too uses very high-quality relays. The design – which switches ground as well as signal connections – ensures that only the selected input is connected through to the 525 electronics, the remainder being isolated. By buffering all signals immediately after the input, the 525 presents only a minimal load to source devices. Both balanced and unbalanced inputs are available.

Dual-mono construction

As few components as possible in the signal path speak for an unbalanced circuit concept. In this case, the lowest possible stereo conversations can only be achieved with a consequent dual-mono design. The analogue circuits and the associated power supplies of the left and right channels are physically separated from one another and are additionally decoupled with filter networks.

Level and phase correct with all loads

An ideal preamplifier like the 525 maintains perfect level accuracy and phase accuracy regardless of load. But measured values are only part of the story. Ultimate sound quality should always be the first priority. At no time should distortion, noise or hum be allowed to colour the music.

Perfect power

In order to drive the longest of signal cables, the output stage of a preamplifier must be sufficiently power­ful to do the job. The 525 employs a powerful, very fast and ultra-wide (2 MHz/– 3 dB) output stage that can drive long cables with ease. We team that with a similarly robust, high specification switched-mode power supply which features high-precision and extremely low-noise linear control circuits. Backed by more than 400,000 μF of storage, the power supply of the 525 provides virtually unlimited pulse power with indiscern­ible levels of noise.

Audiophile transparency

Musical transparency is pre-eminent in the 525. Colouration is simply not a factor. Control too is at the 525’s heart: stereo imaging precision is exemplary while sound sources appear perfectly focused on the sound stage. Once you audition the 525 you will come to understand the true nature of sound and the importance of the right preamplifier in achieving it.

Mains 220 – 240 V (50 – 60 Hz)
100 – 120 V (50 – 60 Hz)
Power consumption < 0.5 W standby
100 W device in operation
Inputs 2 × balanced (XLR)
2 × unbalanced (RCA)
Input Impedance XLR:
820 kΩ
47 kΩ
Outputs 1 × balanced (XLR)
1 × unbalanced (RCA)
Frequency response (– 3 dB) 0 – 2 MHz
THD + N < 0.00009% (20 Hz – 20 kHz)
Signal-to-noise ration 120 dB
Channel separation 130 dB @ 1 kHz
Gain max + 15 dB
Volume control range + 15 DB to – 79 dB in 1 dB steps
Output impedance 10 Ω balanced (XLR)
10 Ω unbalanced (RCA)
Output voltage 16 VRMS balanced (XLR)
8 VRMS unbalanced (RCA)
Output current max 0.2 A (limited)
Dimensions 442 × 143 × 448 mm
(W × H × D)
Weight approx. 20 kg
LINK (remote turn-on) 12 V control signal


A CD or SACD player brings both digital and analogue domains into an audio system. For the very highest quality sound every part of the player is critical. A high-quality D/A converter alone is no longer enough. The 746 unites a top quality optical drive, a super-precise master clock generator, an intelligent digital signal processor with over­sampling, and analogue output stages of the utmost quality. Together they ensure nothing in the music is lost on its way from disc to output connection.


As with its Series 7 sibling the 560 D/A-Converter is packed with cutting-edge tech­nology with one objective – the love of music. The parallels include a consistent dual mono design in the output stages and separate power supplies for digital elec­tronics and the analogue stages. The 560 D/A-Converter adds a digital volume control that allows direct connec­tion to a power amplifier.

D/A conversion

Burr-Brown devices perform D/A conversion only. Their internal upsampling and filter stages are not used. The output currents are converted to voltage and then filtered. With an internal bandwidth of 40 MHz, this current/voltage conversion stage allows best signal-to-noise performance and maximum dynamics in the analogue domain.



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