General Guitar Gadgets Silicon NPN Fuzz face Problem

[mattstrat]

Hello all.

I just built a General Guitar Gadgets Silicon NPN Fuzz face. It works fine and all of the voltages at Q1 & Q2 are good, however, I am getting an obnoxious loud pulsating noise, especially if the guitar volume is all the way down or all the way up. The noise is still present with the guitar anywhere in between. I checked all the wiring and all looks good. Like I said, the pedal works great just crazy loud noise.

Any suggestions? I did try using shielded wire for the input, grounded at one end, at the input jack but that made no difference. Electrolitic caps are of the right value and are placed correctly.

[idy]

Are you using a battery or power supply? Is it in a box?

[mattstrat]

Thanks for the reply! It is in a box and it does this with either a power supply or battery.

[Matthew Sanford]

Does the effect pot change it at all? Is it there on the bypass? Also, sounds like it is always there when the effect is on, does the rate or volume of the pulse stay constant no matter your settings?

Oh, and welcome to the forum!

[tigger6]

Sorry if this is stupid, but is the input/output sleeve wired correctly? I presume to the negative ground?

[mattstrat]

Does the effect pot change it at all? Is it there on the bypass? Also, sounds like it is always there when the effect is on, does the rate or volume of the pulse stay constant no matter your settings?

Oh, and welcome to the forum!

Thanks!  No noise when bypassed. The noise does not change in rate when adjusting the pots that I can tell just when I turn the guitar volume all the way up or down, it gets louder.

[mattstrat]

Sorry if this is stupid, but is the input/output sleeve wired correctly? I presume to the negative ground?

Yes

[mattstrat]

The noise I'm getting is like a motorboating, sputter sound. really weird. Mt cell phone's camera doesn't work or I'd try and post a short audio clip....

[Clint Eastwood]

The noise I'm getting is like a motorboating, sputter sound. really weird

Did you include the optional C6 to decouple the power supply?

[Matthew Sanford]

Search motor boating on the forum, RG gives a great explanation on a 2005 post in regards to phase shift and the RC decoupling at power supply input. I think these guys here are right, and that is where you should focus

[antonis]

What they say..

[Matthew Sanford]

https://www.diystompboxes.com/smfforum/index.php?topic=37802.msg266580#msg266580

This RG for technical details. Another excitable post stated a huge 2200u decoupled made them both single again!...or something like that

[mattstrat]

The noise I'm getting is like a motorboating, sputter sound. really weird

Did you include the optional C6 to decouple the power supply?

I held it in place without soldering it to see if it helped but it didn't. Obviously I need to solder it though LOL! I'll solder it in place and try again.

[mattstrat]

What they say..

Yes i'm going to give that a try. Thanks!

[Matthew Sanford]

Just make sure you have the voltage series resistor in there so it does make a low pass to take the warbles out

[mattstrat]

Ok. I added 220uF cap @ C6 (I didn't have a 470uF), added the diode and replaced the output wire with a shielded one. I didn't add the 100 ohm series R yet, I have to fine 0ne.

It was still making noises but when I left my workbench and went into my rehearsal studio, it was much better with a battery or PS. The only thing now is when the guitar's volume is OFF, I get a very loud buzz that is way overbearing. As I turn the guitar volume up, it slowly goes away. Also as I turn the fuzz's volume up or down so does the noise.

So something is happening to the circuit when a guitar's volume is OFF.  Getting there though! Thanks for all of the replies!!!

Oh I just found a 100 ohm r and a 470uF cap to try later.