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AW: [Doepfer_a100] Doepfer A-110-2 triangle glitch

2015-07-21 by yahoo@doepfer.de

> Hello,
>
> looking at the triangle wave of the 110-2, there is a glitch at the end which gives it quite an audible "buzz" on top of
> the triangle sound.
>
> IMG_20150709_174337.jpg
>
>  IMG_20150709_174337.jpg
> View on drive.google.com Preview by Yahoo
>
> is there a way to calibrate that away somehow?
>
> Regards,
>
> Vladimir

In the A-110-2 the triangle is derived from the sawtooth via waveshaping (in case of the A-110-2 that's a precision rectifier which
mirrors the sawtooth wave when it reaches negative values). Sorry - there is no trimming potentiometer available. As a rule you will
always obtain a glitch when a triangle or sine is derived from a sawtooth. The reason is that the "reset" of the sawtooth is not
infinitely fast but takes a while. In reality a sawtooth is consequently an extremely asymmetric triangle with a slow slope (the
typical sawtooth slope) and a very short reset slope. This reset slope is what you see as a glitch in every triangle that is derived
from a sawtooth by means of waveshaping. The only way to remove it would be a tracking filter or the usage of a triangle core based
VCO like the A-111-1 (or the planned successor of the A-111-1 high end VCO, but this module is still under development).

Best wishes
Dieter Doepfer

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