I could use some of you guys expert aid in helping to decode this problem. Built the Deep Blue Delay with Mods 2. It does delay, repeats work, delay time works. It also distorts like it's a dirt box. Seriously, it's like I built a Madbean Sparklehorn, dirt and echo in one effect, with just a hint of background oscillation. I've tried changing the PT2399 to see if it was the chip to no effect. I've tried changing the 78L05 to see if that was the problem to no effect. Everything appears to be in order so I'm hoping one of you might now in which direction I should be looking.
Using a DMM I'm measured the following values on the IC's on the solder side.
OP275
1. 917 8. 4.95
2. 4.58 7. 4.57
3. 4.56 6. 4.54
4. 4.54 5. 0.00
Does it distort at all settings of the volume pot? If so, the symptoms sound like your op-amp gain resistors are wrong. Double check the values of the 360k and 180k at the top left, the 22k and 20k at the top center, and the 5k1 and the volume pot at the top right.
Actually, your 78L05 should have 0V on the ground pin. It's linked to pins 3 and 4 of the PT2399 and pin 4 of the op-amp. Are you sure you measured that right?
I did a quick remeasure and I think I had measured the ground pin of the 78L05 wrong, its indeed 0v. I will check the resistors later this evening. Thanks for pointing me into a general direction. Hopefully it will yield some results.
The 100uf cap was soldered wrongly, with the positive lead now coming into contact with the track connecting the 5K1 resistor and lug 1 of the volume pot. Resoldered and now it works as it should. Couldn't have done it without your help, induction, thanks for pointing me in the right section of the build.