Rene Schmitz wrote: > Today I completed the construction of an 566 VCO with expo current control. Did you think about the possibility of using a XR2206 instead of a 556? The 2206 too has a current input for frequency control. Many years ago I planned a VCO with the 2206 and the expo converter from the Formant. But I dropped this as the Curtis chips appeared. Ingo