Klark Teknik DN-410 Parametric Equalizer, in good working condition.
This dual-channel device features five filters per channel, with all bands fully configurable between 20Hz and 20kHz. Each filter offers cut and boost of –25dB and 15dB respectively, with available bandwidth settings of 1/12th to 2 octaves. Further, it may be configured (via a front panel switch) to be a single channel of ten filters if required. It is fitted with high and low pass filters for each channel and signal relays that ensure that audio signal reaches the outputs even in the event of power loss. All filters are individually switched in and out of circuit, plus an overall channel bypass switch is fitted. DN410s are found in many applications, most commonly in theatre or AV situations where omnidirectional lavalier or lectern microphones are used.