Dark rift external modulation

[Riccardo Turacchio]

Hi folks! I ordered a Dark Rift board and I'm wondering how difficult would be to add the option of external modulation.....from the schematics seems pretty doable....if I add a switched mono jack between R32 and the Depth pot I'm pretty sure it would work....or am i missing something ??

 

[Riccardo Turacchio]

I had another idea...add also an LFO out from R32....really useful to modulate other pedals in sync

 

[BuddytheReow]

What do you mean when you say "external modulation"? The DEPTH knob controls the amount of LFO bleed into the PT2399. You can turn it fully CCW to essentially turn off the LFO and have just a delay pedal.

Or are you looking to highjack just the LFO section into another circuit?

 

[Riccardo Turacchio]

Well ...for "external modulation" I mean that if I interrupt the connection between the LFO and the Depth pot with a switched jack maybe I can use other sources to modulate the pt2399...like CV sequencers, envelopes or simply an expression pedal....
For the rest...I was checking the schematics and I saw that basically the on board LFO/modulator can be tapped at the connection between R32 and the Depth pot
So why not making it available with a jack output? Can be always useful to have it....

 

[Riccardo Turacchio]

Let me try to explain it better
Basically I would wire 2 jack from R32
One that brings the LFO out
And a switched one (LFO connected on the switch part) so that in case I plug an expression pedal or a sequencer the Depth will "attenuate" the external modulation source and not anymore the LFO

 

[gonzo]

Wouldn't splitting a wet out do what you want minus the CV sequencing? Like run only the repeats into other effects such as modulation.

 

[Riccardo Turacchio]

.mmmhhh...no...the LFO is a modulation source...no audio....

 

[Riccardo Turacchio]

So I can confirm
It actually works!!
Now I have LFO out and external modulation input to use with other modulation sources
When the shape is on square wave the LFO is even strong enough to run the sync of my Volca FM as a clock!!
Now ....what else can I squeeze out of this pedal..?.....

 

[Chuck D. Bones]

Interesting!

Driving the PT2399's VCO input with an LFO or external signal is a bit tricky. The PT2399 fixes the VCO input at 2.5V. The current drawn out of the VCO pin controls the internal clock freq. Draw too much current and the clock osc latches up.