424 Gain Stage

JHS replicated the preamp circuit from the Tascam Portastudio 424 MKI cassette multi-track recorder—the lo-fi workhorse that Mk.gee famously plugs straight into for his elastic, saturated guitar tones. When vintage four-track recorders became modern pedal platforms, Josh Scott tracked down the exact UPC4570 and NJM4565 op-amps from the original 424 MKI and built a pedal around them.

The circuit captures the rubbery clean headroom and smashed-out fuzz character of recording direct-to-tape through cassette preamps. Trim, Channel, and Master volume knobs work in tandem like the original recorder's three-stage gain architecture. Bass and Treble EQ shape the response. Soft-touch switching with buffered bypass keeps it silent during performances.

Quarter-inch output pairs with balanced XLR DI for studio integration. At 50mA draw, it powers the tape-inspired preamp character without the mechanical hassle of actual cassette machines.