Built an effects pedal for my guitar. It doesnt work :(

[bboy_jon]

I bought this kit

http://www.generalguitargadgets.com...facturer_id=0&option=com_virtuemart&Itemid=45

I built it, and well from what i can tell I did everything correctly (obviously i did not since it isnt working :/ )

Heres the schematic and parts layout

https://www.electro-tech-online.com/custompdfs/2008/05/ggg_ff5_lo_npn.pdf

https://www.electro-tech-online.com/custompdfs/2008/05/ggg_ff5_sc_npn.pdf

For some reason. When i plug in a 9v source (power supply or battery) The LED goes dim as i turn the 500k (volume) pot clockwise. If i turn it ccw it goes bright and then it goes out if I turn it all the way CW.

It doesnt seem to do anything when I plug my guitar and amp into it. If i have the pedal turned off, a loud noise/hum is produced through my amp. When i turn the pedal on the noise goes away. Whether the pedal is off or on the sounds from my guitar dont make it to the amp.

Any ideas as to why the LED would go out as i turn the pot?

 

[Nigel Goodwin]

Any ideas as to why the LED would go out as i turn the pot?

There's no way it can if it's connected right, you've almost certainly wired the switch wrongly (perhaps turned it 90 degrees?).

 

[rjvh]

it sounds that you short the suply some how with turning the potmeter

first of all check all conections from wires component solderings make sure that no shorts are made

on an other not does the device behave the same as there is no guitar is pluged in it could be that the equipment that you conect to it cause a problem

do you have a multi meter to make some basic checks???

Robert-Jan

 

[bboy_jon]

Yes i have a multi meter. And yes it acts the same without the guitar plugged in.

All of the wires to the switch are connected how they should. Does the position of the switch matter ?

There is what looks like a 2 on one of the corners of the switch. I didnt think that mattered.

 

[audioguru]

I think the input jack is the wrong type (it is supposed to be a stereo jack) or it is wired wrong (the tip is supposed to be audio, the ring to the negative terminal of the battery and the sleeve to ground).

The mono plug from the guitar is what connects the battery to ground because its long sleeve shorts the ring to ground in the jack. Without the mono plug, the battery is supposed to be disconnected then the LED will not light.

Hum indicates that a connector is wired wrong.

 

[audioguru]

The switch in the picture doesn't show which terminal is which. Maybe it is turned 90 degrees from what it should be.
Use the multimeter to measure continuity in the switch.

 

[Nigel Goodwin]

There is what looks like a 2 on one of the corners of the switch. I didnt think that mattered.

Like I said earlier, it's almost certain you've got the switch 90 degrees out of position, it would cause all your problems.

 

[bboy_jon]

yeah in the pics of it completed in the instructions the switch is side ways (terminals are sideway)

Ill fix it hopefully today and hopefully that was my only prob

Thanks

 

[bboy_jon]

so yah you guys were right. All i needed to do was turn the switch 90 degrees. Thanks

 

[bboy_jon]

so heres the problem, it doesnt sound how it should sound.

Heres what mine sounds like

https://www.zshare.net/audio/11534658d9e796fc/

It is going like this

Clean, then with overdrive on, then with distortion, then with my pedal.

It should sound something like this

**broken link removed**

it just sounds like my overdrive though :/

Any ideas? I made an audio probe but i dont know what i should be looking for. With the audio probe, at some points (such as the collector on Q2) i can hear the actual guitar sounds through the amp, on most of the other points if i touch them i just hear a slight change in hum/noise...if that what i am supposed to be looking for?

 

[audioguru]

It sounds pretty fuzzy to me. My poor ears. I hate distortion.

The input impedance of the Fuzz Face circuit is much too low for a guitar pickup so the output of the pickup is loaded down and is too low.

You need to add a high input impedance buffer circuit made with a vacuum tube or a FET.
Here is a FET guitar buffer:

 

[bboy_jon]

well the circuit i made is proven to work and it should sound like the second clip i linked. I should not have to modify any of the components

 

[audioguru]

well the circuit i made is proven to work and it should sound like the second clip i linked. I should not have to modify any of the components

Then maybe you must use a guitar pickup that matches the lousy old circuit.

there are discussions about the Fuzz Face circuit in Google. They say the circuit heavily loads down the guitar's pickup so for it to sound nasty the guitar must be played very hard. They say if the guitar is played normally then the distortion is minimum.

 

[bboy_jon]

like i said though, i should not have to change any of the components. I get what your saying though. Its probably true but my pedal still shouldnt sound like overdrive.

 

[crutschow]

So the idea is, fix it but don't change it.

 

[audioguru]

So the idea is, fix it but don't change it.

The Fuzz Face circuit is not the same today. It was designed a few hundred years ago with selected germanium transistors. It sounds different with modern silicon transistors. It also sounds different through a modern amplifier and speakers that have very low distortion.
Maybe the guitar pickups made today are also different from the old ones.

 

[blueroomelectronics]

So the idea is, fix it but don't change it.

Use the force.

I've never found wishful thinking vs technology to be a winning proposition.

 

[bboy_jon]

look guys. The pedal i built is this

https://www.musiciansfriend.com/product/Dunlop-Dallas-Arbiter-Fuzz-Face-Pedal?sku=151214

here is a sound file of what it would sound like

**broken link removed**

If i plugged my guitar into that pedal it would produce that sound...or atleast something similar.

I don't have to change any parts. The components and circuit for the fuzz face works... it is known to work.

 

[blueroomelectronics]

Are your geetar and amp identical to the one in the video?

On the other hand if you're convinced the design is fine then the problem must be your assembly. Can you try it with someone else's gear?

PS AudioGuru knows his stuff, if he said it's wrong I'd listen.

 

[audioguru]

Bboy Jon's first post shows an expensive kit with modern silicon transistors.
He want a circuit that sounds like the extremely distorted recording that has its amp turned up so high it has feedback and produces sustain.

The recent picture of the case of a circuit has nothing to do with the circuit inside but they say it uses the obsolete old germanium transistors.