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DIY Stompboxes => Building your own stompbox => Topic started by: Bill_F on January 09, 2004, 05:24:34 PM

Title: AD-3208 echo
Post by: Bill_F on January 09, 2004, 05:24:34 PM
http://www.generalguitargadgets.com/v2/index.php?option=displaypage&Itemid=156&op=page&SubMenu=

Just finished building this and after messing with the trimpots (theres a lot of em) I'm getting a pretty nice delay. The only problem I'm having is the LED won't turn off. Is that a millenium bypass built into the circuit? Is the wire coming off of the bottom left of the switch in the diagram the control wire? AND does anybody have any suggestions how to fix this? I've checked for solder bridges etc. and can't find anything. I guess I could throw in a 3DPDT (that should sort the LED out) but I'd like to use some of the Carlings I have if possible.

Thanks all,
Bill
Title: AD-3208 echo
Post by: Jason M. on January 09, 2004, 06:30:10 PM
Hi Bill,

It is a nice delay, isn't it?
Scott Swartz did a great job designing it.

There is a millenium bypass built into it.

To fix it and make the LED turn on and off to indicate status, you have to reverse one of the diodes. The layout diagram shows it the wrong way.

It is the one located just above the 1 M trimpot.

With the diode wired as shown in the diagram, current is allowed to flow to the LED regardless of switch status. That's why it won't turn off. Reversing the diode fixes this.

Have fun.

J.
Title: AD-3208 echo
Post by: Bill_F on January 09, 2004, 06:52:16 PM
Hey Jason,

Thanks for the info. It is a nice circuit. It should do the slapback thing I was looking for perfectly.

Thanks again,
Bill