Adding an LFO to a PT2399 Delay


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Does anyone have any experience of adding an LFO to a deep blue delay style pedal or any other PT2399 delay for that matter?

Fuzz dog includes a pad available in the link below for one and I was interested to see what others had done. The pad attaches into the delay pot and the resistor of pin 6.

Does anyone have any experience of adding an LFO to a deep blue delay style pedal or any other PT2399 delay for that matter?
You might want to have a look at the bottom of this post
Necro-bump! Let's discuss this in more detail, because sometimes I need things spelled out explicitly. Perhaps someone else does too.. I actually had to reference a few schematics for this one, because adding an LFO is not a drop-in mod for the DBD circuit. It is easy though.

In order to add this:

DP Mod Schematic.jpg

Grind Customs DeProfundis Modulation Daughterboard Rev2.png

Do not follow the advice of CowYoghurt on Reddit:

"You could add modulation to the repeats! I used this layout* for mine. It's designed for use with the deprofundis delay, so you need to make a few modifications for it to work with a dbd. You need to connect one leg of the LDR to a 2k2 resistor and then to ground, and the other leg to the middle pin of a On-Off-On spst switch. Then you connect one of the remaining pins to time 1 and the other to pin 2 of the pt2399. That way you should have modulated delay in one position, just delay in the center position, and a pseudo chorus in the other position."
*the vero layout I've attached to this post

Sorry, CowYoghurt. It didn't work for me. Instead, take a look at the PPCB Seabed and notice how the Delay lug 1 is connected directly to ground on one side, while the minimum resistor connects lugs 2/3 and pin 6 of the PT2399:

PedalPCB Seabed Delay - PT2399.jpg

Whereas the Magnetron and De Profundis' Delay pots have a minimum resistor on the ground side of the Delay (Time) pot and the other side connects directly to Pin 6:
PedalPCB Magnetron - PT2399.jpg GC De Profundis - PT2399.jpg

So here’s what I did with reference to the Seabed schematic:

• R17 - replace resistor with a jumper
• Clip lug 1 of the Delay pot, install 2.2k minimum resistor between clipped leg and the PCB pin. (Should be leg > resistor > PCB ground)

When the DP daughter board instructs you to connect a wire to [Time 1], connect it to the pot leg itself, not the PCB. Voila!


And here’s a short 1am sound clip of the cool chorus sound and the modulated repeats:

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Hey, thank you @coltonius for such a detailed breakdown. However this particular issue has been driving me nuts for days and I've tried many posted solutions without success. Simply, I want to add the DeProfundis daughterboard (as per the same Vero layout you posted) to a Bow Echo PT2399 delay without the on/off/on switch - I just want full-time modulated delay. Whatever I seem to try gives me either delay or modulation but never together.

As the Bow Echo has a resistor before the time pot to ground, I replaced it with a jumper then added a 2k2 between lug 1 and the board. I connected 'Time 1' from the daughterboard to lug 1. Then connected the other side of the LDR ('Sw2') directly to lugs 2&3 on the time pot, to emulate the switch in the modulated delay setting. With the LDR connected to lugs 2&3 I get modulation only, disconnected I get delay only. I tried multiple combinations of the wires and lugs but could not get both on together. It seems like it shouldn't be this hard but I'm clearly doing something dumb...

Any suggestions gratefully received, thanks! BOW_ECHO_SCHEMATIC_V1.png Grind Customs DeProfundis Modulation Daughterboard Rev2.png
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