Hi everyone,
As you can see I'm new to the board so first of all a big THANK YOU to slacker for this awesome pedal and all his feedback to other people creating mods..I've gone through all 40 pages in the last couple of days and I've learned a lot! So yeah I'd like to build some version of the Echo Base myself (without the modulation bits)..unfortunately I only discovered it when I had already ordered all parts for a Rebote 2.5, but I'm pretty sure I can improvise with the parts that I have.. Since I've got quite some customising coming up anyway I've been trying to really understand all the pin assignments of the PT2399. The data sheet is a joke except for pins 1-6 which are pretty much self-explanatory, and I can't find the description of pins I thought I remembered from somewhere early in this thread..but let's try, based on the audioprobe-results:
16. LPF1-IN very quiet signal
15. LPF1-OUT delay
audio in, which makes sense since the signal has to go through an LPF first before being digitised.. Do I get it right that this is actually the input and output of an OpAmp, the two resistors before 15/16 controlling the gain? (sidenote: if I use a 10k/47k combination on the setup that I've got on my breadboard right now (pretty much the "typical configuration" setting from the datasheet with 10k/15k) I get some serious distortion, which might indicate just that.) And the 470pF cap between the two pins acts as yet another LPF?
14. LPF2-OUT loud delay with cyclic noise
13. LPF2-IN nothing, or possibly a very quiet signal
Anybody got a clue why there should be another LPF in the chip, particularly one for the output?
12. OP2-OUT delay with hiss
11. OP2-IN very quiet delay with hiss
10. OP1-IN very quiet delay with hiss
9 . OP1-OUT delay with cyclic noise and hiss
Pretty clueless, particularly about 9 and 10.. Can anyone with more experience with the PT2399 tell me what difference the cap between 9 and 10 makes?
Here somebody mentioned an effect on the internal clock bleeding through (which I also encounter when turning the delay pot past 40k), the post isn't clear about influences on other sources of noise though..
A lot of questions for a first post I know, but hopefully some of you can share your experience with customising the thing..will go straight back to meddling with it myself now

Best!
Kevin