Simple Tails mod for delays.

[madbean]

Here's a tails mod that I've been playing with. It comes right from the Small Time delay posted on DIYSB, so credit goes to ValveWizard.

The pdf contains all the info you need to implement it on just about any PT2399 delay (you can use it on analog delays, too).

[LaceSensor]

Thanks for making this available. Im tempted to give it a whirl soon not sure what on.

Can you comment on which of your pt2399 pedals to your knowledge change the dry signal so this set up would be undesirable?

[LaceSensor]

anyone help me out where A and B go on a rebote 2.5 ?

http://tonepad.com/getFile.asp?id=98

[midwayfair]

anyone help me out where A and B go on a rebote 2.5 ?

http://tonepad.com/getFile.asp?id=98

The 1uF cap after pin 7 of IC1.

[LaceSensor]

Thanks. I have one on vero I'm going to try the tails mod on.

[LaceSensor]

Here is my vero. Hope using your images / information was ok?
Ive given what I feel is the appropriate credit.

[madbean]

Sure, sure...no problem Thanks for doing a vero!

[Hangingmonkey]

Thanks for the vero

[madbean]

One thing I did not mention in the doc: I highly suggest using the SPDT over a 3PDT. Not only because you only need one set of switches, but also because the mechanical noise of toggling the SPDT is greatly reduced. It is a much quieter switch and that is quite important when toggling a delay on and off.

[matropiero]

Hi!
Thanks for the schematic and the vero (in the vero I think the transistor is wrong placed).
But I have a question: this can be done in a true bypass pedal? And is it possible to change between bypass (with trails mod) and true bypass in the same pedal?
Thanks!

[LaceSensor]

Hi!
(in the vero I think the transistor is wrong placed).

Hi

Can you explain why? It looks right to me...

Ian

[matropiero]

Hi!
(in the vero I think the transistor is wrong placed).

Hi

Can you explain why? It looks right to me...

Ian

In the schematic the "source" leg of the transistor is connected to C2, but in the vero C2 is connected to the "gate" leg.

[madbean]

Yup, he's right. Gate is the the bottom lead, not the middle. The pinout is DSG with the transistor facing left.

[midwayfair]

But I have a question: this can be done in a true bypass pedal? And is it possible to change between bypass (with trails mod) and true bypass in the same pedal?
Thanks!

All this does is block signal by shunting the connection from the dry path at the input of the delay line -- it can't "bypass" anything. If you want something similar, check out the millennium bypass.

I have a couple technical questions:
-What keeps the delay line seeing 4.5v so that there isn't a DC offset when it's switched on? Or alternatively, why isn't that an issue in this setup? (This was a problem I ran into when I did tails on the Multiplex.)

-Why is the decoupling cap with tails 1/10 the size of the original?

[LaceSensor]

Yup, he's right. Gate is the the bottom lead, not the middle. The pinout is DSG with the transistor facing left.

ok ill fix it