supplementary information : PT2399 clock sync delay (Patreon)

https://note.com/solder_state/n/nf6dc0a61e26d

Supplemental information for clock sync delay module.

1.Calibration Method

In the attached excel file, there is a simple picture and a graph of the approximate curve.

If you have any questions about calibration, please contact me.

2.Calibration error

The delay time is predicted by finding a power-law approximation curve of the delay time in the calibration.

Since this is an approximate curve, there will be an error from the actual delay time.

The table below shows the actual delay time measured by my module and the delay time predicted from the approximation curve.

The maximum error is 14msec.

Since human senses cannot perceive sound deviations of 50msec or less, the error of 14msec is considered to have no effect.

3.Circuit Tuning Points

The 120k Ohm resistor connected to pin D9 is for adjusting the delay time. A smaller resistor value (e.g., 100k ohms) will shorten the delay time. However, it may exceed the normal operating range of the PT2399, in which case an unpleasant noise sound may be generated.

The 10k Ohm resistor to the left of the 4.7uF capacitor on the left side of the FeedBack POT adjusts the amount of feedback. If this resistor is 15k ohms, self-oscillation in the feedback can be eliminated. If self-oscillation is eliminated, it is easier to use as an effect, but it will not be able to produce extreme noise sounds.

The 33k Ohm resistor in the upper right corner of the MIX POT adjusts the output volume of the PT2399 effect sound. Selecting a smaller resistor value (e.g., 22k ohms) will increase the volume of the effect. However, if the effect volume is increased too much and the audio output exceeds 10 Vp-p, there will be an adverse audio distortion effect.