The preamp power supply case not only contains the two battery power supplies for the audio circuits, but also a third conventional power supply, which supplies the control circuits and the display for the preamplifier. Of course, all three power supplies are electrically isolated from each other. This goes as far as that three cables are necessary for the mains connection – the Line and Power Block might well become the favourite preamplifier of all cable manufacturers. The audio part of the preamplifier consists of four blocks: the anterior one, which contains the circuit boards for control and monitoring electronics, as well as the display and the operating controls for volume and input selection choice. The cases for signal processing of the two stereo channels are found at the back on the left and right side. The slightly shorter block in the middle has the – unfortunately single-ended – input sockets for the phono preamplifier in the back as well as a single-ended headphone socket in the front. Therefore, when using them, the otherwise strictly separated grounds of the left and right channel have to be connected per relay.

For the phono stage the gain can be selected by menu including the input impedance for Moving Magnet or Moving Coil cartridges. A Subsonic filter can be activated and for MC cartridges loads are available at 10, 15, 30, 40, 50, 70, 100, 200, 300, 600 and 1000 Ohms and for MM pickups capacities at 50, 100, 150, 200, 250, 300, 350, 400 pF – all comfortably adjustable by remote control. For this and only this, BlockAudio goes the easy way and packs the Alu-Remote from Apple as a remote control. The control block of the preamplifier also has two RJ-45 sockets. If they are connected to the power amplifiers, you not only can switch them on remotely, but you can also choose between Class-A continuous operation, Auto Eco or Eco mode. In Eco mode the Monoblock in idle state only uses 50 Watt instead of 500 Watt in Class-A operation. If Auto Eco is chosen, after 15 minutes without audio signal at the inputs of the power amplifiers, the system will automatically switch to the power-saving Eco mode and the bias current is only increased, once an input signal is present.