Formant - the Elektor music synthesiser 
Parts 4 and 5, October and November 1977. In Part 4, Rl in the input adder  circuit  (figure  7)  is  shown  as  
l00 k.  This gives the `Octaves, coarse' control  (Pl ) a range of + 7 1/2 octaves. At a later data  it was decided to reduce this range  to + 5 octaves. In part 5, this modification was carried out : in figure 2a, R 1 is shown as 
150 k; the front panel layout  (figure  3)  shows a  `coarse' range  from -5 to +5. 
However, we forgot to point out that  the value of R 1  shown in figure 7 of part  4 is `incorrect'. Furthermore, and more seriously  the  octaves/Volt adjustment was based on the original value of  R 1 .  This means that the Octaves/Volt   adjustment procedure described in part 5 is incnrrect.  For the adjustment procedure uslng a  DVM  and  a  frequency  counter,  the connection between the slider of  P1 and R1  must first be unsoldered. The free end of Rl is then connected to ground, and the slider of  Pl is connected to the KOV  input  with  S1  in  position  'a'.
Adjustment  can  now  proceed  as  described in the original article.
The second adjustment procedure, using the  beat  note  method,  is  correct  as originally described.