Grounding Issue, Can somebody confirm?

[Dylfish]

Hey Guys,

I made a diy protoype board last week with power, a switch and jack in/out. I just went to breadboard my first booster on it and whenever I connect power or ground to the breadboard rails there is a huge buzzing and all guitar signal cuts out.

The other issue is thats I'm using a BS170 MOSFET and even without any power and im still getting my clean signal thought without any voltage on the gate, although this is probably just a breadboarding error.

This is a video of whats happening. you can see what happens once i plug the power in and then into the circuit. Any help would be great. Thanks

http://youtu.be/AmAxnng_azI

[R.G.]

In order of likely mistakes, the list is nearly always:
1. Incorrect part orientation/pinout
2. Incorrect wiring
3. Soldering issues

You're here enough that I think you're probably past #3, but everyone will always have issues with 1 and 2. Start there.

Once you're past those, your description seems to indicate that the circuit is oscillating. Both 1 and 2 can do that, but there are also possibilities for RF oscillation, expecially with MOSFETs, and expecially on breadboards because of the high resistance of the joint contacts, and the high stray capacitance.

[Dylfish]

Yeah the one that got me is that the clean signal is still going without any power to the fets gate (apart from the signal itself)  so there shouldn't be any conduction between drain and source. 

I've checked components but I'll have to keep looking :-D  I was worried I might have not connected the ground of the dc jack to the audio jack but I've stupidity made it hard to open up again so I'll try rearranging components.  Could having a ground loop also be an issue?