Precision Instrumentation recorder HP3964 4 tracks

Instrumentation Tape recorder 4 channels (HP 3864A)  using ¼” magnetic tape in 7” reels.
Six tape speeds:15/32 ips to 30 ips controlled by precision servo system.
Direct signal / FM recording/reproducing
Bandwidth (Direct Signal) 50 Hz to 2010 Hz at 15/32ips to 64000 Hz at 30 ips.
Bandwidth (FM)  DC to 156 Hz at 15/32ips to 5000 Hz at 30 ips.
S/N 38 dB (Direct Record) 48 dB (FM Record)
Flutter compensation (improves S/N 4 dB to 12 dB in FM mode
ThD < 2%
Input Level. 1 V to 30 V (adjustable continuously)
Input Impedance 100 kohms//100 pF
Output level: 1 to 5 v peak to peak
Linearity: 1% from peak to peak output
Internal signal calibrator
Meter functions: peak, AC,DC, input or output
FM e-e mode (record/reproduce connection bypassing the path heads)
Microphone input and headphones output and  small loudspeaker
Dimensions: 427 x 400 x 256 mm.
Weight 29.5 Kg  
Power 100 to 240 V AC  110W

In questo link sono elencati 393 modelli, di cui 361 con immagini e 138 con schemi.
Elenco delle radio e altri apparecchi della Hewlett-Packard, (HP); Palo Alto, CA