Type 69 Passive Equaliser
The original Type 69 was produced in a number of different versions - the early ones being developed while Dick was at Olympic Studios and the later versions for Island and others. The principal differences related to the transformer type and whether germanium or silicon transistors were used. Since Helios was a custom console manufacturer, these differences were quite normal.
Type 78 Active Equaliser
This was based on the last consoles delivered in 1978/79, offering active equalisation with all parameters continuously variable.