Vref mod for PT2399 delay

16/10/2013 If you are building a delay with the PT2399, this might be a useful addition,
inspired by the little angel but designed for modular synth CVs.
I made myself some boards a while ago, pretty standard design.
But read about the "little angel" pedal which modulates the Vref pin, so decided to give it a go.
Ended up with a completely different design, but one that should suit modular voltages. I fed this a 20Vp-p signal with no probs.
The cap may help reduce clicking when feeding it gates, then again clicking might be good.
You may want to adjust the resistor to suit, I was happy with 47k, seemed to give the most swing without hitting the rails.
Diodes are just to prevent the chip seeing negative voltages or anything over 5V.

Got some really weird effects putting the signal from a VCO in here, synced with the audio source VCO.