In 2023 the system got reconfigured in a tube/SS hybrid bi-amp configuration. The signal from the preamp gets split between separate amps for the midbass/tweeter and the main woofers. Twin stereo tube amps have an inline high pass filter ~ 65hz, and are run as single channel mono blocks to power the 5" midbass and tweeter. A solid state power amp was added to power the main woofers , and it also feeds the powered sub. An active crossover was added as a low pass filter to limit frequencies above 63hz to the integrated amp, and the original passive low pass filter of the main woofers has been bypassed. The speakers were made by my small company in Rochester, NY around 1990, and are the heart and soul of my system. They were the culmination of years of being in business and around the business. Focal 8K kevlar woofers in a transmission line, Focal 5k mid-bass with an aperiodic chamber that dumps into the transmission line, modified Seas tweeter, proprietary crossover with top shelf components. The crossover has it's own chamber, is wired with Kimber Kable teflon coated OFC copper, Litz wire inductors, CAT caps, Dale non-inductive resistors. It took around 5 years to dial the values before I moved them inside the speaker in 1995. Each driver has its own solid copper input.