The BiAmpPro is an all-in-one solution in Bi-Amping your speakers. Everything is on one pcb. This is made possible by leveraging on chip amps and configuring them as active crossovers.
In the simplified schematic above, the tweeter amp is a TDA2030A. Instead of a bandpass filter at the input, the chip amp includes a 3rd order (18dB) High Pass. For the woofer, the input is a 2nd order (12dB) Low Pass. Two TDA2050 in mono-bridge are used to drive the woofer. In using the chip amps in this manner, there’s no need for another electronic crossover.
Since this pcb will be inside a speaker, it’s imperative that the inputs are balanced. We don’t really know how far away the speaker will be from the preamp or the mixer. So to have the input balanced is prudent. After the balanced amp is a potentiometer. This is used to adjust the volume of the tweeter. This is necessary because the sensitivity of the tweeter is generally 5dB~6dB more than the woofer.
The BiAmpPro pcb measures 5.2″ x 2.75″, fairly compact considering what’s on it.. On board are a 8A bridge rectifier, four pieces of 3,300uF capacitors totally 13,200uF, voltage regulators and a single dual op amp. The TDA2030A tweeter amp is at the top left. The other two are the TDA2050 in mono-bridge mode for the woofer. When in bridge mode, the woofer must be 8Ω because each TDA2050 will be seeing 4Ω. Be aware that using a 4Ω woofer will destroy the TDA2050.
With this pcb, you only need a power transformer and a heatsink to complete your bi-amping. It can’t get simpler than this. My next update will be the pcb proper, followed by bench testing.
March 7, 2022Amplifiers