Nagra IV-SJ – Stereo Nagra for instrumentation and logging. Pots are replaced with selectors to set gain in precise steps, no limiters, and when present, the microphone inputs are for high-voltage unbalanced instrumentation mics rather than low impedance balanced with T-power and phantom. Amazing frequency response specification of 25 Hz to 35 kHz at 15 ips-38 cm/s, Wow and flutter: 0.05% (15 ips).
You can also analyze very low frequencies as the IV-SJ has a 10:1 speed range with the 4th speed adaptor, from 1.5″/s to 15″/s, so you can analyze 2.5Hz signals by playing translation across this speed range.
You can follow NAGRA on their social media :