This is one of the remarkable 2 channel digital equalizer ever made by Yamaha using lots of audio grade parts – Elna audio cap, RMA resistors and Muse etc… The digital receiver is YM3436C x 2, YSF210 digital filter and PCM63P-Y x 2. IV is 5238 and LPF is NE5532.
Both DEQ5 and DEQ5E can be used as a standalone DA converter using AES digital input and thus it is a good reference DA converter but the maximum resolution is only 20 bit. The sound is wonderful and full which can easily better than many today DAC.
Some internal pictures:
