feedback loop help

[tomchagolla]

Let me apologize in advance, i know a lot of people are probably sick of questions about this simple pedal. i know because i searched the hell outta this forum and saw many discussions on this, but still didn't find what i was looking for.

i want to build a feedback loop with a bypass switch, but i would like to use a stomp for the bypass an i want to have an LED for each the effect and the bypass.
can someone please draw this up for me, or if this is already drawn up somewhere else can you please point me in the right direction

[Dave Z]

well, if you can read a schematic:

http://www.generalguitargadgets.com/v2/diagrams/ts_fulldive_1_sc.gif
http://www.generalguitargadgets.com/v2/diagrams/ts_fulldive_2_sc.gif

both have switches doing funky stuff to the feedbackloop. And LEDs. And bypass. So there ya go.

If you cannot read a schem, well, look around on GEO they have some drawings, also the "beginners project" here shows you in photos how to wire stuff...but really, reading schems is a necessary skill, will save you many headaches!

[smoguzbenjamin]

Welcome to the forum

Before you can consider really getting into pedals and electronics, you're going to have to be able to read a schematic. It's a necessary evil I now spend all day staring at them :mrgreen: The only advice I can give you about how to read them is look at the FAQ's on aron's site, and practice LOADS. Copying a schematic down, even when you only have a vague understanding of what it does, helps a lot to recognize different components, and after a while you can predict what a specific piece of circuitry wil do by just looking at the schemmo.

Practice makes perfect

[Marcos - Munky]

Copy and paste the link in another window:
http://www.geocities.com/munkydiy/loop.jpg

[petemoore]

Which way is the switch 'facing'? NM/>
 Better yet what's the basic idea here?
 B [output], somehow is fed back to the -OA input [?], but it looks like they have an indicator LED?>l..which makes it confusing to sort out.
 So: :?  Say I wanted feedback on all the time [without the switch], what would be a basic topology for the feedback circuit loop between output and OA -input, as related to the above schematic [for reference, the #1 schematic]?

[tomchagolla]

Welcome to the forum

Before you can consider really getting into pedals and electronics, you're going to have to be able to read a schematic. It's a necessary evil I now spend all day staring at them :mrgreen: The only advice I can give you about how to read them is look at the FAQ's on aron's site, and practice LOADS. Copying a schematic down, even when you only have a vague understanding of what it does, helps a lot to recognize different components, and after a while you can predict what a specific piece of circuitry wil do by just looking at the schemmo.

Practice makes perfect

I'm in the process of learning how to read schematics, I just recently bought electronic projects for musicians. I picked a feedback loop as my first project because it seemed a lot less involved then other projects, so I could realy just work on soldering.

Munky, thanks, I think I get it, but I only see one LED.

[tomchagolla]

also, would it be benificial(sp?) at all to use perf board for this project?

[Marcos - Munky]

Let me see if I understandood it right. You want a feedback loop, like the Total Sonic Annihilation, that you connect a pedal in the loop and when you press the switch you create a feedback loop in the effect to generate noises, or you are talking about the feedback path in distortion circuits, when you use one input of the opamp for the signal input, then pick the output and route it to the other opamp input? I believe you are talking about the first one. If yes, you can use my schematic and add another LED for the "off" status, but This isn't necessary, because only a LED showing when it's on will be a effective indicator. But if you want two LEDs, build it like in the schematic. You will use a DPDT switch, with one pole to put the effect on and off and another pole to put the LED on and off. Connect the "LED" pole of the switch to ground like in the schematic, then add another LED with the - side soldered to the remaining throw of the "LED" side of the switch. Connect the LED + side to the +side of the other LED.

EDIT: I saw your last post, and if you're talking about a distortion with feedback path you can use perfboard. If you're talking about the feedback loop to put effects in the loop like I said, you don't need any board.

[tomchagolla]

Ok, this is the drawing I'm going off of....

http://experimentalistsanonymous.com/diy/Schematics/Feedback%20loop.gif

So, It has an SPST switch to use it as just an effects loop, i want to replace that switch with a DPDT stomp switch, plus I would like to add an LED to indicate when the effects are being bypassed (or not being bypassed, i'm not sure which would be best), and an LED to indicate when the effect (feedback loop) is on.

Thanks for putting up with my lack of knowledge

[Marcos - Munky]

You can pick this draw and use my description about the LEDs in the DPDT switch (the one that is an SPDT in the draw).