PRODUCTS : ELECTRONICS : BPA768-484-B
The BPA768-484-B with the big knob. The light of all the 22 LEDs appear as a decent blue ring.
The Power Final Stage in the behold system can be used as a Bi-Amping final stage. It serves in this configuration as a mono block with two identical outputs, in case e.g. if one wants to control two loudspeaker systems parallel without connecting these in parallel, however, physically.
As a Classic Stereo Final Stage it can also be operated. This, however, requires longer speaker cables. Switching between Bi-Amping and Stereo Mode is performed in the pre-amp. APU768.
For 5.1 ... 7.1 three to four BPA768-400 as a team are then very well suitable for the six/eight required channels. At 5.1 one is used for left-front and left-behind, a second one for right-front and right-behind and of course the third one for center and bass.
The Specials at the construction of the BPA768: The behold BPA768-484 contains - unlike all other High End Power Amps - three important equipment functions in one case which have characteristics desirable today as well as in the future:
The Power Conditioner in high end audio systems is generally arranged for the complete system first to the power supply. This is generally not required at behold. The pre-amp APU768 has a separate switching power supply for this task. At the final stages the power conditioner is functionally integrated in PFC-part of the the power supply. By that arrangement the converting part of the power supply of the final stages is provided with "cleaned" current. Even when using two BPA768-484 blocks at stereo operation the function blocks do not influence each other.
The D/A-Converter is arranged together within the final stage. Becaues of that there are no connecting cables between the converter, voltage amplifier und the final stage buffer and consequently there are no distortions of the audio signal. A further advantage results from the fact that the signal processor is aware of the volume and is able to control the final stage in the best possible way in it's operating point.
Analogue Final Stage is also not built up conventionally. It is equipped with full symmetrical transimpedance amplifiers instead of old-established difference amplifiers or tubes. The regulation of spacing current is not analogue but digital with the advantage that no disturbing analogue regulation or protection circuits impair the analogue path. This means it's a digital real time idle current tracking.
