squeal output for metal simplex guitar

[mattmunee]

Hi everyone,
This is my first stompbox project.  I've built Howie's Metal Simplex (http://www.diystompboxes.com/pedals/mtlsim.bmpb) stompbox on a prototype breadboard, and something is not quite right.  You can definitely hear distortion, but there is tons of noise and a heavy, persistent screeching sound.  What's even more confusing is that for the highest setting on my guitars tone knob, the screech is even more pronounced, but it drops off almost immediately when the knob is turned just below 10.  If anyone has suggestions, I'd be very interested to hear.

I also had some questions that may answer my first.  Since the box is connected to a 9V battery, I wasn't sure how to ground everything.  Should the ground be connected to the negative side of the battery.  Also, should the ground connection for the input and output jacks be connected to the negative side of the battery, or should the grounds from the jacks bypass the circuit altogether, and simply connect the jack grounds via a jumper cable?

Lastly, although the diagram calls for 2N3904 transistors, Radio Shack only had one, so two of my transistors are actually 2N4401.  I'm not sure if this could have any effect here.  I've read that these two are interchangeable for most applications.

Any thoughts?

Thanks.

[deadastronaut]

connect jack grounds to board and negative to board too....all are grounds.

all are negative/ground/ battery - ...ok.

not sure of the 2n3904's..but i would stick to 2 of the same....

[oldrocker]

Think of the batteries negative terminal ground period.  All grounds will eventually connect there.  Including input / output jacks.  When using a stereo jack as a plug in power on device, the unused outside ring grounds the battery to the rest of the circuit.

[mattmunee]

Thanks for the responses.  I talked to an electronics guru at my work, and he suggested that just cleaning up the wiring job may get rid of the squealing.  That worked.

There is still something fishy:  When the tone knob on the guitar is set all the way to 10, the noise level drops dramatically and the distortion sounds great!  However, backing off the tone knob just a touch brings up the noise level and drops the output level.  Also, the sound seems to fade in and out.  This is very confusing to me.  Any suggestions?  It's still only on a bread board, but I don't see why this would have anything to do with the tone knob effect.  Really, I don't see why the GUITAR's tone knob would effect the noise level at all.