How can I make a guitar fuzz effect

[Jesus@wp4mhl]

I was searching in the iternet and I want to make a fuzz effect for my electric guitar. Because I found one and not work. Can anyone help me?

 

[Theatronics]

Fuzz is just a VERY BAD amp. The classic sound is the Jimmy Hendrix sound.
I attached the circuit that makes that sound when driven by the right pickups.
I am not sure what pickups he used.  I am guessing they were just stratocaster single coil pickups.  Humbuckers came along later.

If you are getting clean sound or a very weak effect your pickups might be too weak.  If you can't afford new pickups try heavy strings for slightly more output.

You can also add a pre-amp on the front of the FUZZ circuit (A fet input Op_amp would be enough) 

can you send the circuit you were using along with what it was doing. Maybe you already have one built and just have a component in wrong. 

-Mike

View attachment 39513

 

[Jesus@wp4mhl]

OK this is the circuit that I have used I don't remember from were I got this but this is.

View attachment 39514

 

[Theatronics]

SORRY, SORRY.

 

[Theatronics]

Your circuit is set up as a inverting Op-Amp with Clipping.
The first part of the circuit is the two 100k resistors,
They form a Virtual Ground for the OpAmp.
The 741 is designed to run on a dual supply. By
Cutting the 9v in half, the 4.5v that appears at pin 3
Appears to be the ground for the amp.

I am not sure what the purpose of the 100uF cap on
The low side of the divider is.  It may have been intended
To filter out noise and keep the ground steady.  In truth,
As the current is drawn from the battery the source voltage will
Drop and the 4.5v will drop also.  If the battery gets low, sudden
Current drains could cause the Virtual ground to fall BELOW
The stored voltage of the 100uf Cap.  As the input resistance
Of the 741 is nearly 20M, it is likely the entire circuit could
Shift sound as the battery goes dead.  I’d drop that part for now.

The next part of the circuit is the feedback loop.
Without the diodes the feedback is (1M / 1K) or  X1000
The 1N4001 diodes then short out that formula at any
Voltage above 1 volt.  (Under 1 volt the diodes tend to
Act like resistors – Look up ‘Knee Voltage’)
That means that any input signal will be allowed to see normal
Amplification unless the output exceeds 1V Pos or Neg.

The remaining capacitors are just DC blocking. They let the Audio
Signal through while blocking any stray DC between the guitar, The effect and the Amp.

My first test would be to check for 4.5V at pin 3. (Assuming you have 9V at the battery)
Pin 3 should be

 

[audioguru2]

I think that guitar pickups need a high impedance load like 1M ohms. The clipping opamp circuit has an input impedance that is very low at 1k ohms. The heavy loading on the pickup reduces its level.

 

[Theatronics]

Yes, Guitar Pickups are very Hi-Z devices.
But the input Z of an OpAmp with feedback should approach
10meg Ohms or more. Even without the feedback loop
a standard 741 has a 2meg input on it.

My gut is telling me the chip may have been damaged.
I have seen a lot of 741s go south quietly.  Some had
some strange failures where they seemed to work
but only partly. 

-Mike

 

[audioguru2]

But the input Z of an OpAmp with feedback should approach 10meg Ohms or more.

No it doesn't!
The negative feedback in an inverting opamp circuit creates a "virtual ground" at its inverting input where the input and output signals cancel. Therefore the input impedance is the input resistor.View attachment 39515

 

[Theatronics]

First let me say that the Texas Instruments datasheet is wrong....
Op-Amps are not for everyone.  My brother in-law for example. 

Secondly let me say...
    Wellll.ExcuuuuuuuUUUuuuuse me. 

Forgot my Inverting vs. Non-inverting rules for a sec there.
(shesh so picky.)

Heres my best (and feeble) attempt at a NON-Inverting, HI-Z input
Version of the same circuit..

Go ahead , rip it up.  I know you are dying to..

I'll take my hurt little feelings over here and calculate some Hfe gains
until I feel better.

-Mike

View attachment 39517

 

[audioguru2]

Go ahead , rip it up.View attachment 39518

 

[MP1]

I was searching in the iternet and I want to make a fuzz effect for my electric guitar. Because I found one and not work. Can anyone help me?

Jesus,
There is nothing wrong with the design of your fuzz circuit. In fact, it is an older classic fuzz circuit from the 60s or 70s as I recall. I recommend that you check for mis-connection. Also, I would recommend that you replace the 1N4001 diodes with 1N914. You could even replace these with LEDs and the circuit would work. Also, I suggest that where you have a 1Meg ohm resistor, make this a 1K ohm resistor with a 1M pot in series. This will give you a level of fuzz adjustment. Note that it will also act as a volume control.

MP

 

[audioguru2]

Would this work? : http://www.aaroncake.net/circuits/fuzz.htm

It is the same circuit as the opamp circuit by Jesus a couple of days ago.
Its 1k input imedance is too low for a guitar's pickup.

 

[MP1]

It is the same circuit as the opamp circuit by Jesus a couple of days ago.
Its 1k input imedance is too low for a guitar's pickup.

R3 has no direct effect on the impedance of the guitar pickup. The value of R3 is selected to provide two things:
1. amplification with respect to the feedback resistor and
2. Filtering as per calculation with C1.

You guys missed the input cap. Jesus and Aaron win the prize with the effect that will not load down the guitar pickup as the volume is changed.

MP

 

[Jesus@wp4mhl]

the circuit in the web link posted is that I was posted (I supose) and if I place an pre amp using an LM386. This will work?

 

[MP1]

Don't use an LM386 as a pre-amp. It will be too much for your guitar amp.

MP

 

[Jesus@wp4mhl]

If I place this Pre-amp will work

View attachment 39532

 

[audioguru2]

R3 has no direct effect on the impedance of the guitar pickup. The value of R3 is selected to provide two things:
1. amplification with respect to the feedback resistor and
2. Filtering as per calculation with C1.

You guys missed the input cap. Jesus and Aaron win the prize with the effect that will not load down the guitar pickup as the volume is changed.

MP

Sorry MP but you are wrong.
R3 is the input resistance of the inverting opamp amplifier which is 1k ohms. The 0.47uF input coupling capacitor has a reactance of 1k ohms at 340 Hz, so the load to a guitar pickup is only 2k ohms at 340Hz and less at higher frequencies.

Many experts say that a guitar pickup must be loaded with a very high impedance:View attachment 39533

 

[audioguru2]

If I place this Pre-amp will work

Not very well. The LM386 is a small power amplifier, not a preamp. Just make a preamp with a high input impedance from an opamp.

 

[Jesus@wp4mhl]

Can you send me a circuit for this preamp with an OP-AMP?