Helios Pre/EQ/Comp Racked Pair

These are the last and most powerful channel strips Dick Swettenham designed before Helios went out of business in 1979. They are similar to the so-called 'Type 78' modules, but with a built-in compressor! This is based around a dbx VCA, as used in the classic SSL compressor design. The compressor is a fixed-threshold design -- to achieve more compression you increase the mic gain -- but ratio, attack and release times are fully variable. The compressor can be bypassed and also switched pre- or post-EQ. Other features include -20dB pad, polarity switch, fully variable high- and low-pass filters and three-band EQ with bypass switch. The mic preamp has up to 75dB gain. There is no separate line input. The input transformers are the desirable Sowter 3374 as used in other late Helios designs. However, whereas most Helios modules use 0V and 24V power rails, these run off ±18V which gives them more headroom.

These rare modules have been fully restored by Martin Dowden of Creative Electronic Services, who also built the custom rack units and their internal power supplies. The outputs have been balanced using high-quality transformers, and Martin also added switchable phantom power and output attenuators, which allow them to be driven as hard as you like without overloading downstream equipment.

One of the modules is missing three coloured knob caps; this one also has a new 3374 input transformer as the original had failed. Each rack contains two modules.