| The A-designs Pacifica, P-1 and EM series 500 modules all have an extra high impedance buffer that routes the signal through the input transformer.
The typical design is to bypass the input transformer and send the signal straight into the amplifier. This turns the mic preamp into a line amplifier. This is fine for low impedance sources including synthesizers and guitars and basses with active pickups and low output impedances. When we deseigned the Pacifica the first proto used this concept. Although it sounded good the sound really came together when we switched to a pre transformer active buffer. A lot of A-designs customers are professional bass players so we always put extra care into acheiving an excellent bass sound.
The extra high impedance active buffer is especially necessary when using a bass with passive pickups like a Jazz bass, P-bass or Rick. These pickups have much higher output impedances and prefer a higher load impedance from the amplifier they are feeding. The A-Designs discrete input buffer presents a 2megaohm impedance, the proper source to load ratio for a passive bass pickup. This is a design element that sets apart all high end direct boxes whether its an Evil twin, Reddi or Littlelabs D.I.
Jon Erickson |