Maestro Fuzz Tone No Output

[Helmholtz]

Are you getting (guitar) sound?
Which transistor in which position?
Did you install transistor sockets?
Do you have a scope?

[x-pro]

Didn't you take transistors apart when you were a kid?)
The cap is carefully filed with a file along the perimeter of the base. after that it is removed and part of the leads is exposed, sufficient for accurate soldering.

[misterc57]

Are you getting (guitar) sound?
Which transistor in which position?
Did you install transistor sockets?
Do you have a scope?

I have guitar signal with fuzz effect, ,but loud crackling mixed in.

What I am seeing for V all negative...

NTE158 (sub for broken lead 2n270)
Q1C 2.8
Q1B 2
Q1E 1.9

NTE158 (temp sub, still have the original 2n270 available)
Q2C 2.5, varies 2.1 to 2.8
Q2B 60 mV, varies
Q2E 0

2N270
Q3C 2.5
Q3B 0, varies
Q3E 0

I do not have sockets.
Scope available.

[misterc57]

I have since swapped Q3 with a new NTE158, still noise.

Swapped the first 20u coupling cap, still noise.

If I lift the first 20u cap there is no noise.

Note that all swaps are temporary to try and find the source of the noise.

[Helmholtz]

I have since swapped Q3 with a new NTE158, still noise.

Swapped the first 20u coupling cap, still noise.

If I lift the first 20u cap there is no noise.

Note that all swaps are temporary to try and find the source of the noise.

Means that the noise is coming from the input stage or maybe from the battery.
Try wiring a 100µ cap from Q1 collector to ground, positive of cap to ground.
As your battery voltage is only 2.8V, I don't think it's fresh.

[misterc57]

Means that the noise is coming from the input stage or maybe from the battery.
Try wiring a 100µ cap from Q1 collector to ground, positive of cap to ground.
As your battery voltage is only 2.8V, I don't think it's fresh.

I will try that but I have another update.

Focusing on the input stage I realized that there is a additional .01 cap between the input jack and the base of Q1, which is not in the schematic. I have removed that .01 and the noise has diminished significantly.

The input jack is still going through a 10K and .01 cap, although the schematic indicates it should be a 100K

Now the noise seems to be controlled by the attack pot. When at zero these is no noise and as you dial up the attack pot the noise increases.

There is guitar signal and fuzz effect at the output.

[Tom Phillips]

Ever since this thread began I have wondered about the "Corrected" schematic. This one, and others posted, do not show the ON-OFF (AKA Clean vs Fuzz) switching. Given that this basic feature is missing, I wonder if there are other mistakes in the schematic.

[mozz]

Q2C should vary more when turning the pot. Q1E should be lower. Are you sure of the pinout? Try your freeze spray on Q1 when playing the guitar and see if it sounds better.

[Helmholtz]

Ever since this thread began I have wondered about the "Corrected" schematic. This one, and others posted, do not show the ON-OFF (AKA Clean vs Fuzz) switching.

Sure noticed that as well.
But what effect could the bypass switching have regarding the crackling?

[misterc57]

Q2C should vary more when turning the pot. Q1E should be lower. Are you sure of the pinout? Try your freeze spray on Q1 when playing the guitar and see if it sounds better.

Why would my V be off?

Yes on the pinouts. NTE158, triangle shape, E, B, C with B on the top of the circle. 2N270, E, B, C with C at the far end.

Spray on Q1 did not change anything.

Spray on Q2 deadens the noise but also seems to decay the guitar signal.

Overall regardless of noise the signal seems to decay fast, no sustain on notes.

Tried a 100u on Q1 C to ground, no change in noise.

Cleaned battery terminals. Installed new batteries. Now 3.2V power. No change to noise.

As I increase attack pot setting, Q2C V drops and gets more noise.

[Helmholtz]

Time to scope a sine signal.
Input signal should be very small, maybe 10mVpp

Probe at Q1 emitter, Q2 collector and Q3 collector.
It should be possible to see the noise as well.

[mozz]

I'm figuring it's mis-biased, but you also have a noisy transistor in there. They are not easy to get sounding good.

[misterc57]

Wanted to have a baseline. I have placed back the 2N270 in Q2 and Q3. So new parts now are Q1 (NTE158), C2 (20u) and C3 (20u).

Noise is now more predominant than when all 3 transistors were all new NTE158.

I have @ 13 mV 1K AC signal injected with pots dialed up to 10.

Below are scope images in the following order. Probe at Q1 emitter, Q2 collector and Q3 collector.

[mozz]

You need to follow it from the start. Show me a nice sine wave on both sides of the 100k, then the .01, then directly on the base of Q1. I would be running a little hotter input , maybe 40-50 mv. Turn the fuzz pot to half. volume doesn't matter.

[Helmholtz]

The scope pics don't give a clue regarding the crackling.
Does the baseline jump sporadically?
First pic shows a signal with a lot of hiss/noise, but might be scope noise floor.
Second and third pic seem to indicate a trigger problem.
Either the probe's ground lead is not connected to circuit ground or you didn't select the proper trigger source.
When using CH1, the trigger source should be set to CH1 as well.

How does the crackling sound anyway?
Can you hear it with the sine input signal?
Can you hear it with no input signal at all?