Triple True Bypass Loop

Started by HyperMusic, December 23, 2009, 06:24:40 AM

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HyperMusic

Hi,

I'm building a triple looper (my first DIY) following this scheme:


But there are some problems:
* first LED does nothing
* second and third are always on, 2.3 V, and when I hit the switch they get as designed 9V.
* Get no sound at all trough the pedal.

So it doesn't work at all

This is the current situation:

Resistors: 1k5
3PDT footswitch
9V DC JAck

Anyone got a clue what's wrong?

flo

#1
Measure the resistance between all connections that should be connected together, especially earth, and verify that the resistance is 0 ohm (or something very small).
Measure the resistance and check that connections on the jack tips are not connected to earth = have a very high resistance.

Make a simple audioprobe and follow the signal from input jack tip via all sends and returns jack tips to the output jack tip:
http://www.diystompboxes.com/pedals/audioprobe.jpg
http://www.geofex.com/FX_images/audioprb.gif

Worry about the LEDs after the signal path is debugged.

R.G.

I don't really know this, but I would guess that you may be using the 3PDTs rotated 90 degrees from the way you think they work.

Especially with a square array of pins like the 3PDTs, it's easy to get them off one way or the other. How do I know this?  :icon_biggrin:

Use your multimeter set to ohms and verify that you have the switches rotated the right way.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

KazooMan

#3
I agree with RG that rotation of the switches is a likely culprit.  However, if these are the standard 3p2t switches like you get from Small Bear they appear to be wired correctly!  Pretty strtange.  The multimeter will tell for sure.  Perhaps you have some other brand and the lugs are oriented differently.  As RG said, we have all been there, done that.

Another thought on the first LED.  Do you have the polarity correct?

I looked at an enlarged version of your picture and the solder joints and wiring look fine.  Let us know how this turns out.

boogietube

+ 1 on the rotation of the switches. They appear to be oriented incorrectly. That was my first thought when I looked at it.
Pedals Built- Morley ABC Box, Fultone A/B Box, DIY Stompboxes True Bypass box, GGG Drop in Wah, AMZ Mosfet Boost, ROG Flipster, ROG Tonemender, Tonepad Big Muff Pi.
On the bench:  Rebote 2.5,  Dr Boogie, TS808

KazooMan

Here's a picture of the 3p2t switch I got from Small Bear (it's the one I mentioned in another post where I secured one of the lugs with some epoxy since the red epoxy had cracked).  I just confirmed the connectivity with a multimeter and it is a s shown in the picture.  Unless the switch in HyperMusic's photo is a diferent brand then I think he has it wired right.


R.G.

Quote from: KazooMan on December 23, 2009, 01:29:12 PM
Here's a picture of the 3p2t switch I got from Small Bear (it's the one I mentioned in another post where I secured one of the lugs with some epoxy since the red epoxy had cracked).  I just confirmed the connectivity with a multimeter and it is a s shown in the picture.  Unless the switch in HyperMusic's photo is a diferent brand then I think he has it wired right.
That's why I said "meter".  Meters don't look at photos and guess, or be fooled by brands, or by changes between manufacturing runs in the same brand.

One thing's for sure: there are only two options. Either it's wired wrong or the switches are not what he/we think they are.
R.G.

In response to the questions in the forum - PCB Layout for Musical Effects is available from The Book Patch. Search "PCB Layout" and it ought to appear.

GeToChKn

Is it me or does it not look right with power going directly to the LED's and the resistors connected to ground?

jkokura

Quote from: GeToChKn on December 23, 2009, 06:17:52 PM
Is it me or does it not look right with power going directly to the LED's and the resistors connected to ground?

I also wondered that. I thought the resistors go between the power and the LED... Nobody had said anything about it, so I thought maybe I had it wrong.

flo

The LED and resistor must be in series. It does not matter which one comes "first".

HyperMusic

I metered the switches. They appear to be wired correctly. Also followed the hot signal through the circuit, which is correct but gives no sound at all...

Quackzed

plug a chord into the input , and another into the return jack off the first dp3t ,measure resistance between the tips and again after stomping the first dp3t, if in either position you get 0 resistance, the switch is flipped 90'
nothing says forever like a solid block of liquid nails!!!

Sic

didn't look at it long, but i did notice one of the jacks was a stereo jack... are you using stereo cables? and/or is the stereo jack wired correctly?


KazooMan


Good catch on the stereo input jack.  It is hard to tell from the picture, but it looks like the wrong tip is wired to the first switch for the input.  If so plugging in a non stereo plug would just connect the input at switch 1 to ground.  That would explain the no signal, but I don't see how it would effect the first LED. 

To the OP.  Try just shorting out that LED by bridging between the resistor and ground.  If the LED doesn't light it is either wired up with reversed polarity or it is burnt out.

bumblebee

Another thing is you don't need all them ground connections on the jacks as you have an aluminum box grounding them already so adding ground wires is achieving absolutely nothing and just overkill.

You just need to ground the LED's.

moose23

Two questions:

Is the ring on the input jack connected to anything?

Have you an audio probe? If so check for signal from the input right through the pedal and see how far you get. Do the same with each loop connected back to itself.
If you don't have one you can use the continuity test on your multimeter do the same thing.

HyperMusic

No, only the sleeve and tip.

No, I have no audio probe.

moose23

In that case use the continuity tester and see how far the signal gets, keep one end on the input tip. My bet is a cold solder joint somewhere along the way.

flo

Make an audioprobe with a capacitor and an old guitar cable. This makes following the audio signal very simple!
http://www.diystompboxes.com/pedals/audioprobe.jpg
http://www.geofex.com/FX_images/audioprb.gif
(See also my first posted reply...)