The preamplifiers power supplies are as complex as the power supply of the power amplifier. Each of the power supplies, which feed the audio circuits, consists of a toroidal transformer and 120,000 Mikrofarad filtering capacity. This is followed – again channel separated – by the highlight, a battery power supply with rechargeable lead-gel batteries. These batteries have sufficient capacity for around 15 to 20 hours of listening pleasure in pure battery operation, before they automatically recharge. During battery operation there is no connection to the mains voltage and in theory, the mains power cable could even be disconnected. From the batteries we then move to the audio circuits in the upper case. Here, 4-pole capacitors from Mundorf take care of the further filtering and decoupling, before we finally move to the discretely built linear regulators that sit on the audio circuit boards. With this concept, Jiri Nemec takes account of the fact that batteries directly on the audio circuits with no further measures, by no means guarantee outstanding sound.

All audio circuits in the preamplifier are simple and discrete. The topology is similar to that of the power amplifier: differential input amplifier with JFETs and voltage amplifier stage with MOSFETs. The output power amplifier with bipolar transistors of course works in pure Class-A operation and has a very low output impedance of 25 Ohms. For the true balanced operation, per channel two of these amplifier circuits are used, so that the result is an output impedance of 50 Ohms. The volume attenuation is built with relays, which can be controlled digitally and shift precision resistors from Vishay Dale. Good sound does not only involve clever circuitry concepts, but also outstanding parts. Here BlockAudio does not compromise: In the power amplifier as well as in the preamplifier, only highest quality parts are used. Equally important is the mechanical build-up of the devices for which the influence on the sound is often underestimated. Jiri Nemec follows the concept to keep the audio signal path as short as possible and to completely forego cable connections. The case itself has the quality of a vault. How far attention to detail can be taken, is seen in the preamplifier: the vertical circuit boards with the volume control and the 4-pole capacitors are coupled to the case through a communal T-piece, in order to inhibit vibrations.”