> Can the new a131 sound clean if you turn down the input level or does
> it always distort Is the distortion a hard clip or a soft clip

Adam,

There are two factors at play here. The distortion is caused by the inherent non-linearity in the 3080 chip that actually does the voltage control amplification (in a v2 A-131) - a triangular wave input can come out looking more like a sine wave. As Bakis says, the component values seem to have been deliberately chosen so that one can operate in the non-linear region if you want to - to avoid it, the level pot on input 1 needs to be set below about 7, and if using input 2, its pot needs to be below about 4 (input 2 is more sensitive than input 1, and if both are used together, they may both need to be lower still).

My use of the term 'clipping' was probably misleading for the other effect - the waveshape itself is not actually clipped, rather the maximum gain available is limited, and if the output from an A-140 is fed into the (unattenuated) CV1 input, this limit is exceeded, and so you get a kind of 'plateau' effect in the envelope, i.e. the 'peak' of the envelope at the transition of attack to decay to gets chopped off. This can be avoided by routing it through CV2 input and adjusting the pot appropriately. I have also looked at whether it would be possible to adjust some component values to alleviate this (as I posted previously). Transistor Q2 is driven into saturation, and this limits the gain-controlling current being fed into the 3080. The saturation point is affected by the value of R9 (currently 15k) - I tried lowering it, and it does cause the 'plateau' to be less wide/to occur at a higher value, but due to the exponential relationship used by the module, small changes in CV result in large changes of the current, and it became apparent that lowering it too much would potentially cause the maximum allowable gain current into the 3080 to be exceeded. It would probably be possible to re-scale all component values used in the exponential converter section of the module, but this would probably mean that the module's performance would not be as good when using CV sources other than an A-140, so attenuating the 140 input is probably the best/simplest solution! (It works for me!)

Tim

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