Scott bernardi PT2399 VC delay

[Sebo]

In the first page, 9th post, below the components layout picture is a link to the PDF with the PCB layout.

[pieca]

Hi,

thanks everyone for this topic. I've successfully build this delay !
Everything works as expected but…
I'm using it with my yusynth modular and my vcos output is 10 Vptp, which is really huge for this delay. I have to really attenuate my signal before going to the delay in order to avoid distortion.

Is it a way to attenuate the input level with some resistors change and a way to amplify the delayed signal more (with some resistors change too?)


An other thing I've noticed, is that the direct delay out is out of phase.
This is not the case with the mixed output.

Thanks for your help !!!!

[pieca]

Ok, I've found the trick!

il order to be able to works with my Yusynth Oscillators (10v Ptp), I have to attenuate the input before going to the PT2399 first.
for that, you have to put a resistor between the signal and the group to booth inputs.
After that, the PT2399 will stop saturate.

But, your signal is going to be very weak…
so you have to amplify it…
for that, IC2A will let us to boost the signal
lowering R8 to 10k and changing R9 accordingly to your input attenuation will do it


Hope this will help…

[Sethkaine]

I've gotta try this out.

[jbeuckm]

[j.baars]

i did make a eagle pcb design, sort of.
with gerber files.

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vcdelay.zip
Description:		Download (listen)
Filename:	vcdelay.zip
Filesize:	12.39 KB
Downloaded:	638 Time(s)

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vcdelay.zip
Description:		Download (listen)
Filename:	vcdelay.zip
Filesize:	12.39 KB
Downloaded:	567 Time(s)

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[acidblue]

Tried to get this work on a single supply , 9v with a 741 and biasing the voltage, but no luck.
Does this absolutely need a bi polar supply?
Might try with +- 9v.
This gave me an idea for a guitar effect box, that's why
I'm trying it with 9V.
But it's not working.

[LFLab]

There are plenty of implementations of this if in stompboxes for guitar, so single supply shouldn't be a probleem.
Check out the diystompboxes and freestompboxes fora.

[wackelpeter]

I would if it should run on 9V first with a DIY pedal like the Echo Base and try to implement the vactrols there like in Scotts design.
Surely then it needs some tweaking there and there, but you have a starting point with a functioning echo unit.
Well breadboard would be the best way to test this out.

I have myself built that Scott Bernardi VC delay and it's a nice unit, but i used a bipolar supply as it's in my rack.

[acidblue]

Thanks guys.
That was encouraging.

[waronheaven]

hello i have recently stepped into your post here, and i have a similar design that i cant make work since months, is a double delay using 2 pt2399 a vca to control feedback and the scott bernardi design for the time, now the vca design is tested and working100% so not sure is that the issue, but the time is not tested so could be that, so far on the pin 14 of the DELAY1 there was no signal at all, only bypassing the time scott design and adding a resistor from pin 6 to ground started to have signal on pin 14, just not delayed and i guess on the output i'm having only the dry of the dry/wet pot.

attached the schematic and the reading of the oscilloscope, blu signal is the original and yellow pin 14


thanks a lot to everyone for the help

here the schematic: https://www.dropbox.com/s/2igs99flcn3eu6z/doubledelay.png?dl=0


and here the reading (blue is original sine and yellow is pin 14
https://www.dropbox.com/s/wthtjr132zhpdv5/IMG_4976.jpg?dl=0

Anthony