Question about the Mad Professor Deep Blue Delay

[mike_c4]

Hi All,

I'm new to the forum, but wanted to ask a question. Using this schematic for the Deep Blue Delay:


What R16, the 2K resistor and C15, the 47nF capacitor doing?

Is that some sort of passive RC filter?

Why is it there?

Thanks for your time!

[Groovenut]

It is exactly that. Its a lowpass filter with a 1.7khz knee that affects the repeats only making them darker on each pass.

[mike_c4]

It is exactly that. Its a lowpass filter with a 1.7khz knee that affects the repeats only making them darker on each pass.

Thanks! I thought so, but I wasn't sure.

Also, what is R15, the 5.1K resistor, and C13, the 22nF capacitor doing? Is that another RC filter for the feedback delays?

Thanks again for your replies!

[anotherjim]

That one is a high pass filter.
In another thread, it is noted that the cap (C13) can be smaller - raises the filter cutoff frequency to imitate the poor bass response of repeats in tape echo.

[mike_c4]

Awesome! That makes sense. Thanks for the replies.