How to mod or make a delay so no dry signal passes.

[makaze808]

Hi, I would like to have a delay unit that is able to pass delays only, no dry, all cheepo units I've tried always have some dry signal (even at level 100%) then the delay happens. What I want is to pluck a string, hear nothing, then the delay occurs and a note is heard.  Is the pt2399 able to produce echo only and no dry?

Thanks for any help.

[Seljer]

Most delays user an opamp as a summing amplifier to mix together the delayed sound and the dry sound. It's usually something like this: http://upload.wikimedia.org/wikipedia/commons/thumb/3/3e/Op-Amp_Summing_Amplifier.svg/200px-Op-Amp_Summing_Amplifier.svg.png

Identify it in the circuit and just remove the line that connects to dry signal. For example, in the Rebote delay http://www.tonepad.com/getFile.asp?id=98 , its the left 24kiloohm resistor on pin 2 of IC2a

[makaze808]

Hi, thanks for the reply, looked in some cheepo's delays I have but smc's, so I think it's time to build an echo base. Thanks.

[CodeMonk]

Came in to post what Seljer said.



Also, I may be wrong, but doesn't the dry signal also connect to the mix knob and you could just disconnect that?

[haveyouseenhim]

Identify it in the circuit and just remove the line that connects to dry signal. For example, in the Rebote delay http://www.tonepad.com/getFile.asp?id=98 , its the left 24kiloohm resistor on pin 2 of IC2a

Would putting a voltage divider to ground in place of that resistor work as a volume control for the first strike of the delay? so you can control how much dry signal passes at first when you hit a string.    Sorry if that doesn't make since. I'm only half awake

[haveyouseenhim]

Anybody?    Oh well.....TO THE BREADBOARD WE GO!!!

[slacker]

Not in place of the the resistor it won't, you need to stick it before the resistor. So clockwise lug of the pot  to the output of the first opamp, wiper to the left hand side of the 24k, anticlockwise lug to vb. That gives you a volume control for the dry signal, turn it all the way down and you get just the delay.

[J0K3RX]

Get a stereo delay and pan the delay all to one side?