Effects Loop Pedal Problem

[peperoni]

Hello everyone.. I'm new here.. I'm building my first TrueBypass Effects Loop pedal.. I've finished it and it is not working. It does the true bypass, but when I switch it on, It makes a awful noise..
I used this schematic:

R1 is 1.5K
R2 is 1M


Anyone has any ideias on what could it be??
Thanks in advance

[niftydog]

What sort of noise is it? One of two things spring to mind;

does the LED work? You may have rotated the switch and inadvertently wired 9VDC from the battery into an input.

Or, the "FX In A" and "FX In B" lines (which more sensibly should be labeled "send" and "return" or something less ambiguous) are swapped around, some pedals do funny things when you feed a source into the output and take the output from the input... if you follow!

[fixr1984]

Is it a ground issue? The resistor on the output going from the ring to the tip has me confused, shouldnt that be grounded?

[peperoni]

The led works just fine.. and it works when in "true bypass" mode.

It makes a loud "HUMMMMM" noise.. 

[peperoni]

anyone has other ideias? or should i just tear it apart a build based on another schem?

[bwanasonic]

This is the diagram I used:

http://www.singlecoil.com/tb-strip/dia1.html

It varies from yours, but I can attest that it works well.

Kerry M

PS - also check continuity of your ground connections on the *loop* jacks with a meter, but I'm pretty sure there is an issue with ground in your schem.

[LyleCaldwell]

I know what the problem is, and I have a further suggestion.

The problem is that your LED cathode leg (battery neg) is not connected to the audio ground, so when the LED is active there will be noise.

My suggestion is that you run a wire straight from the 9V+ to the resistor and to the anode (+) leg of the LED.  Then run the battery neg to the center lug of the switch and then run from the active pole to the cathode leg of the LED.  Much better to switch the ground than the 9V+.

If this unit will be run off a battery, put a stereo jack on the input and wire the battery neg to the ring connection.  If the unit will always be run from a power supply then you can connect the battery neg anywhere to the audio ground.

[peperoni]

Well, Its working! Thanks to everyone. It sure was a ground problem...!! 

No to the next step, the "cosmetics"!!

I'll Post some pictures later on...

Thanks again

[peperoni]

Here goes some pictures.. sory for the quality, but it was with the cellular..