Soulution 757 deemphasis preamplifier

What a difference precision makes!

soulution’s new reference deemphasis preamplifier connects to all analog sources and sets new benchmarks in terms of noise, phase errors, common mode rejection and distortion.

Inputs for MM, MC, tape head

The innovative input stage of the 757 deemphasis preamplifier enables exceptional common mode rejection without compromising the input stage by introducing noise. This is achieved with parallelized instrumentation amplifiers designed for wide bandwidth (2MHz), lowest noise (noise density < -170 dBV/ ) and optimal common mode rejection (CMMR >100dB). This ensures that even the faintest musical signals can be properly received by the 757 deemphasis preamplifier. With its adjustable termination impedance the input can be adapted very precisely to your magnetic pickup system.
When configured as tape head input the 757 activates its tape head calibration network which allows to compensate for roll-offs induced by imperfections of the tape head.

Input for optical cartridges

One of the 757s inputs is dedicated to DS Audio’s optical cartridges. The 757 deemphasis preamplifier features a wideband transimpedance amplifier for optimal reception of the output signals (current) of the optical cartridges.

Gain control

High speed und ultra-low noise operational amplifiers together with relay-switched high precision metal foil resistors form an 80 step (1 dB) gain control unit. Each channel has its own gain control unit also allowing balance adjustment. To avoid unpleasant clicking noises or harmful voltage peaks during gain adjustments, the 757 deemphasis preamplifier is provided with a second gain control path which is active only during gain adjustments. This secondary, IC based gain control alters the gain without any click or pops. Once the new gain is set, the 757 will revert to the sonically superior path.

Deemphasis curves

The 757 provides a wide range of deemphasis curves.

Phono:      RIAA, DECCA, COLUMBIA, LONDON, TELDEC, NARTB
Tape:         IEC2-30ips, IEC1-15ips, IEC1-7.5ips, NAB-15ips

The use of very fast amplifier stages ensures highly accurate reproduction of the selected equalization curve (±0.05dB, 20Hz to 200kHz).

Output stage

The Class-A output stage has been optimised for speed, precision and high peak currents. Thanks to its low output resistance the output stage can drive even long cables without difficulty. With a frequency bandwidth of 20 MHz (-3 dB) and the accompanying minimal phase shift in the audio band, all details of the music are reproduced true to life. The result is a three-dimensional spatial sound experience full of musicality and natural timbres. The sheer power of the output stage guarantees that the rich detail of the music reaches your power amplifier.

Distributed Local Power Supply:

The basis for the dual mono power supply of the 757 deemphasis preamplifier is a switched mode power supply (SMPS) which converts mains voltage into an intermediate DC voltage. Highly efficient DC-DC converters and extremely low-noise and fast linear regulators generate the supply voltages needed to operate the 757 deemphasis preamplifier. Local linear regulators are placed next to each current sink (OpAmp, transistor, etc.). This ensures lowest noise levels on the analog supplies and shortest signal paths. Large filter capacitors, as typically used for linear power supplies with transformers and rectifiers, are no longer required.