Last night I put the finishing touches on the Flux Bender prototype. For those unfamiliar with the name, The Flux Bender is a stereo, passive, 100% vacuum tube powered equalizer (that means no DC powered heater filaments, no silicon rectifiers, no IC's, no solid state voltage regulators, no silicon bullshit period). The EQ filter topology is based somewhat on the Pultec EQP-1A, but its definitely not the same. The amplifier design is a Lightning Boy original.
My goals for the Flux Bender were to create a stereo EQ that offered a higher degree of sonic fidelity and a lower noise floor than Manley's Massive Passive. I wanted to create an equalizer that not only out performs the MP in terms of technical specs, but also in terms of sound quality. I wanted to do all this without the modern solid state trickery used by my competitors... just to prove to the world that solid state components are not needed for great performance, but rather the greatest sound quality and performance can come from a carefully crafted all-tube design. While the Flux Bender won't offer quite as many controls as the Massive Passive, it will offer a lower price tag along with superior specs. On Monday the Flux Bender prototype will undergo extensive testing, but initial tests this morning showed a noise floor of -90.1 dB, which completely blew my mind. First of all, I've only recently broken the -80dB noise floor barrier with revision A of the 1401 stereo preamp. My goal was to match Manley's -85dB noise floor, which seemed to be a serious challenge. I was extremely surprised and overjoyed to see such great S/N performance from the prototype, because the production model will be more carefully constructed to reduce the noise floor even further. This morning I only confirmed the controls and operation of the Flux Bender to be in order. More extensive testing and results on Monday, followed by a complete disassembly in preparation for the first production build of the Flux Bender.
About the Author
Mike Congilosi II, Owner/Designer/Electronics Engineer at Lightning Boy Audio and Owner/Audio Engineer/Music Producer at LBA Studios.