Roland VCF 703 Yves's redrawing

[alanwilder81]

hello Yves,

i am comparing the original Roland 703 VCF schematics to your redrawing of it. It looks that you corrected what i think it's a mistake on the original.

In your redrawing, on the third integrator cell, the resistor R 22 (470 k), coming from the DC offset trimmer wiper, is connected to the 3080 positive input, just like in the other three cells the 470 k resistor goes to the positive 3080 input.

Now, on the original Roland 703 VCF ,and in the third cell only , the 470 k resistor goes to the negative 3080 input.
Why would the third cell configuration be different to the other three?

is that a Roland mistake you corrected, Yves?

thanks for any hint !

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[yusynth]

Yes there is a discrepancy and I haven't checked on the PCB (what I ought to do for sure). Anyway, the trimmer is there to reduce the bleed-through of the control CV. The fact it is connected either on the inverting input or non-inverting input has no importance really. But you're right I will check on the PCB.