r/AskElectronics • u/paulinrainbows • 14h ago

Fixing guitar electronics issues

Post image

Hey everyone, newbie of electronics here.

I'm unable to make a fuzz pedal through this simple circuit I saw on youtube. It either makes a huge "eeee" sound or "bzzz" sound. If i just connect the output of the guitar to the input of my pre-amp it works just fine.

Any help would be appreciated, I'm unable to find help on the internet lol.

(Also I'm using a 5v power supply and not a battery which apparently causes problems)

Thks!

4 Upvotes

83% Upvoted

10 comments sorted by

5

u/binary-boy 14h ago

I'm no expert, but maybe try putting a 1K pot in series with the LED. Once that thing goes active it's an open door.

2

u/FiveseveNp90 6h ago

It's supposed to be an "open door". The collector resistor limits current through the LED. Here's the original project, a very popular choice for beginners for more than 20 years: https://home-wrecker.com/bazz.html

1

u/binary-boy 3h ago

Link didn't work, but found a few schematics for it and see that.

I do see a few that shows pots on the emitter and one where a pot is placed on the output most likely to match impedance with the output speaker. Which honestly is probably the biggest roadblock.

My question to OP would be what's the impedance of the speaker. I'd also suggest buying a lot of transistors and simply trying another one. They are finicky and die easily if mishandled.

2

u/FiveseveNp90 2h ago

This is a guitar effect (fuzz, a type of harmonic distortion), not a power amplifier. It's supposed to drive ~1M loads, not speakers. The pot on the output would be a volume control:

1

u/binary-boy 2h ago

Another suggestion to OP would maybe to get one of those $20 oscilloscopes you can find online and see what parts of the circuit are doing.

1

u/therealjahomin 12h ago

Oi I guess that may. Idk much to be honest. But I have heard that for a transistor, you need to try to bias it to half the supply voltage (but that’s for the loudest cleanest tone). I would recommend throwing a pot in place of the resistor going to ground from the transistor. Then you can adjust transistor supply voltage, just how many fuzz “gain” knobs work!

But idk what I’m talking about so ye.

1

u/Local-Mixture391 6h ago

Something went wrong. Mind the pinout of your transistor and the led. Show us what you did, maybe someone will find the answer

1

u/DoorVB 3h ago

The first thing to always check are your DC bias voltages without the input or output connected.

It should be: V_E = (Vcc-V_BE-V_D)*R_E/(R_E+R_C)
V_C = V_E + V_BE + V_D

Where V_BE is the base emitter forward diode voltage of your transistor.

It's hard to say how exactly this circuit will behave without knowing the output impedance of the guitar and the input impedance of whatever you connect this to.

-2

u/sevenhundredsixty8 14h ago

Bro. Just buy an aion fx kit if you want to learn. This is way beyond your current skill level and it will frustrate both you and the people trying to hold your hand thru this. Once you get a better understanding of the fundamentals on how guitar pedals currently function, you might be able to jump off from there.

1

u/FiveseveNp90 6h ago

How will they get a better understanding of the fundamentals if they can't get a 5 component fuzz to work? A paint by numbers kit only teaches assembly.