750 phono stage



Building the ideal phono amplifier is the ultimate challenge for audio designers. It must work with the extremely low signal levels of moving coil (MC) cartridges while achieving low noise, low distortion, high channel separation and maximum linearity. It must provide up to 80dB gain - equivalent to raising the signal level by 10,000 - yet must exhibit level and phase accurate behaviour while adhering strictly to RIAA-IEC equalisation standards.


The soulution 750 (three MC inputs) and 751 (two MC inputs, one MM input) have risen to this design challenge supremely well. Based on an advanced design around an ultra wide band (1MHz/-3dB) multi-stage amplifier, both are built with the very highest quality components.
For all inputs the gain factor and the terminating impedance are freely selectable. The working bandwidth may also be chosen from either Low (200KHz) or High (1MHz) to within -3dB. To suppress rumble from warped records there is an IEC subsonic filter (<20Hz) which will protect loudspeakers against hazardous cone excursions. On the 750/751 there is also a key to select mono operation.
A front panel level control allows sound level balancing across the three inputs.Phono module (equaliser)
The challenges to the ideal phono amplifier are immense and represent the «pièce de réstistance» for every designer of high-class audio amplifiers. With a gain of up to 80 dB (which equals an amplification factor of 10,000) the amplifier is expected to show a level and phase true behaviour, i.e. an ultra wideband quality (internal amplifier bandwidth 1MHz/-3dB). At the same time it is to compensate the equalisation curve in accordance with RIAA-IEC standards. This can only be realised by means of a multi-stage amplifier concept using super-grade components.

Output stage

The output stage of the 750/751 is optimized for velocity, precision and current capability thus ensuring all the musical detail is passed to attached pre/amplifiers. Furthermore it is stable with interconnects of any length and has a bandwidth that extends to 40MHz (-3dB), ensuring every musical detail is reproduced true to life. The result is a three-dimensional, spatial sound of uncanny accuracy and detail.

Power supply

Above all a phono amplifier needs an electrically quiet environment. To eliminate any chance of interference from the power supply, the 750/751 is powered entirely by either pure DC from an associated 720/721 preamplifier or from a dedicated soulution external supply. This removes any AC mains voltages or stray magnetic fields.



Analogue outputs:
- balanced output (XLR): 1
- unbalanced output (RCA):1

Analogue inputs:
- MC-input (RCA): 3
- MM-input (RCA): -
- Ground: 3


Analogue outputs:
- balanced output (XLR): 1
- unbalanced output (RCA): 1

Analogue inputs:
- MC-input (RCA): 2
- MM-input (RCA): 1
- Ground: 3


Consumption: 19 W
Standby consumption: <0.5 W

Amplification:   +54/+60 dB
Amplification bandwidth

Bdw=High: DC - 1 MHz
Bdw=Low: DC - 200 MHz

Output voltage

balanced: 7 Vrms
unbalanced: 3.5 Vrms

Peak output current: 0.2 A

Output impedance

balanced: 10 Ω
unbalanced: 10 Ω

Frequency response: DC-100 kHz
Slew rate: 400 ns
Distortion (THD+N): <0.006 %
Signal to noise ratio (SNR): >100 dB
Crosstalk: > 60 dB

Input impedance

MC Inputs Settings for MC PDF
MM Inputs (751) Settings for MM PDF

Dimensions (width × depth × height): 480×450×117 mm

Weight ca.: 17 kg