Digital delay basics

[Dimitree]

Hi everyone, I'm trying to understand the basics of a PT2399 based delay..
I don't want to add useless posts to the Echo base topic, so I open this one..but first of all I'd like to thank Slacker for his delay project and his help..

this should be the simplest design for a delay with PT2399:


that orange squares are filter I didn't draw, but those are there.. Those pink are filter I'm not sure if them should be there (if needed)..so this is the first question..
Then, what's the difference between taking the out signal from OUT1 and OUT2?
and, last, where to take the output from the filter around pin 13/14? across the pin 14 (orange wire) or after the join of the 2 resistor?

thank you really much
I hope this topic is not redundant..

sorry for my bad english
Dimitri

[decc]

Just a couple days ago I went over the PT2399 filter structure, but I have to say that one doesn't match the typical delay pedal use. Usually there's a low pass filter on the input and output which are missing here, without which there will be noise. Anyway:

There isn't a difference between out1 and out2 that I can see, and the outputs should be directly from pin 14.

Now on to my question that I didn't want to add to the Echo Base topic. In the LPF1/2 op-amp sections you end up with a structure like this (values from the PT-80):



How does this arrangement work? It looks like a mixture of two low-pass filters and an inverting amp with a gain of 1. I think this is called a Baxandall filter but I can't find an explanation of it. I Can someone spell this out for me?

[Dimitree]

thanks
The filter you mean probably are those that I didn't draw, but I added those squares to remember where those should be.. Maybe you mean the filter before IN and after OUT? I didn't draw that part, this is just the delay signal, not the complete circuit, also are missing the input buffer, output mixer, etc..

[Dimitree]

anyone?