The circuit itself
The input is balanced – Why- cause a cartridge is a perfect balanced source like a micro- phone, and therefore we are using a specially Microphone – preamplifier circuit from the com- pany That, has makes integrated Circuits especially for Audio use.
So the input stage is fully balanced and amplifies the input signal linear.
The Gain, input resistance and the input capacitance can be easily adjusted with Dip switches.
The input resistances can be switched separate for the positive and negative part of the signal between Plus input and ground and minus input and ground.
Either unbalanced mode can be chosen by grounding the negative input.
The ASR Basis Exclusive has 2 separate input stages that can be adjusted individually,
so there are no switches or relays in the input signal path to get full signal quality.
Only after the first stage where you have a much higher signal with a very low impedance the signal is switched between the 2 inputs with relays.
This solution is sonically much better that switching at the input.
After the input selection relay the signal then passes Filters, to provide the necessary Coefficients for RIAA equalisation. These 2 Filters at the extremes of the frequency range -
The first one for very low frequencies, to cut away rumble frequencies below 20 Hz.
This Filter is switchable to 2 Hertz for even better low frequency performance in case the used cartridge / tone arm combination has no low frequency resonances.

The second is at other side of the frequency rand and damps high frequencies above 2122 Hz.

After this the signal is led into the second stage with a high quality/ low noise OpAmp.
There only a very moderate active Filter at 500 Hertz is built in, what means that you a very low gain variation from this stage.

With its very low output impedance the OP-Amp drives the unbalanced output directly without any resistors in signal path.

The Offset of the output stage is regulated.
The negative signal part of the balanced output is made with a phase inverter.