This is a sort of sequel to the article ‘2 × single = 1 × dual’. In this case, two dual opamps are combined to make one new quad opamp. This allows many possible variations, and again it allows two completely different types of dual-opamps to be used. It is very easy to replace a quad opamp if you use the printed circuit board shown here.
The schematic diagram shows the interconnections between the two dual opamps and the pin locations of the quad opamp. The two dual opamps are soldered on top of the board, and two 7-pin contact strips are soldered to the bottom side. These can then be plugged into the socket of the original quad opamp. When selecting the opamps, carefully check their pinouts, as well as that of the quad opamp to be replaced. Nowadays, most types have ‘standard’ pinouts, but there are a few exotic types that do not conform to the standard.
The PCB shown here is unfortunately not available readymade through the Publishers’ Readers Services.