Pedal much more distorted than should be- bias issue?

[Transistor-Transistor]

On the breadboard it sounded great. I must have made the schematic wrong because I've put this into an enclosure twice now and they both sounded the same, super distorted and gated like a bad bias. I'm a total idiot when it comes to biasing so I'd love any help

The sound of it being super distorted is not bad at all though, it's a very unique fuzz. It's just not what I had in mind when I designed this.

[Transistor-Transistor]

At super high distortion settings it has a cool feedbacking/oscillation noise thing going on when you sustain a note but it goes away when you mute the fretboard so thats interesting

Its also like really loud

[J4mes]

Do you get signal after U1A after the 1K? Do you get signal from U1B after the transistors? I.e leg 3 of Q3 and output? Have you made sure the transistors are orientated the right way? I'd start there and work my way in

[Matthew Sanford]

It looks like 560k bringing vref to first op amp, but second pulling it without a resistor, but it's coming through kind of lo-fi. You might try the same big resistor for each one, if it's bias then that may correct it.

[Transistor-Transistor]

It looks like 560k bringing vref to first op amp, but second pulling it without a resistor, but it's coming through kind of lo-fi. You might try the same big resistor for each one, if it's bias then that may correct it.

Theres a 100k bringing vref to the opamp after C2

[Transistor-Transistor]

Do you get signal after U1A after the 1K? Do you get signal from U1B after the transistors? I.e leg 3 of Q3 and output? Have you made sure the transistors are orientated the right way? I'd start there and work my way in

Theres sound everywhere and the voltages look right (to my uneducated eyes)

[m4268588]

How volts of Q3?

[Transistor-Transistor]

How volts of Q3?

Actually they look rather concerning even though I'm not sure what to make of them. Base is 0.681v collector is 142mv and emitter is 41.7mv

Obviously this is bad. Can I fix it if its already soldered in? I made it point to point.

[antonis]

Q2: Make R7 10k and get rid of C4 & R6 (ground Emitter, of course)..
As it is, C4 decouples only a small fraction of total Emitter resistance 'cause r_e (intrinsic Emitter resistor) is more than 500R for about 45μA working current.. Same stands for R6 from DC feedback viewpoint (stability).. R7 value is severely dominated by R8//R9//R11*h_FE (Q3 stage input impedance) resulting into significantly lowering Q3 stage open-loop gain, hence lowering(*) closed-loop gain (R5 / (20k pot + R20))
(*) actually making it more open-loop gain dependent..

Q3: Make R11 1k and R10 4k7.. You can decouple R11 for max gain..
As it is, Collector current is about 20mA, give or take, so Q3 is heavily bottomed (saturated) - you can realize it by that 100mV V_CE..
You could alter R11 value only (say 2k2) but R10 is effectively set in series with R12 (it might seem puzzling but trust me.. ) so the lower its value the more R12 dependable the U1B gain..

[Transistor-Transistor]

Q2: Make R7 10k and get rid of C4 & R6 (ground Emitter, of course)..
As it is, C4 decouples only a small fraction of total Emitter resistance 'cause r_e (intrinsic Emitter resistor) is more than 500R for about 45μA working current.. Same stands for R6 from DC feedback viewpoint (stability).. R7 value is severely dominated by R8//R9//R11*h_FE (Q3 stage input impedance) resulting into significantly lowering Q3 stage open-loop gain, hence lowering(*) closed-loop gain (R5 / (20k pot + R20))
(*) actually making it more open-loop gain dependent..

Q3: Make R11 1k and R10 4k7.. You can decouple R11 for max gain..
As it is, Collector current is about 20mA, give or take, so Q3 is heavily bottomed (saturated) - you can realize it by that 100mV V_CE..
You could alter R11 value only (say 2k2) but R10 is effectively set in series with R12 (it might seem puzzling but trust me.. ) so the lower its value the more R12 dependable the U1B gain..

But how come on the breadboard I used all the same parts and it sounded how it should? What would have happened?

For more context on why I can't change any values, I built the original on the breadboard and it sounded good and normal so I made the schematic and tested everything and bought enough parts from Tayda to make 11 pedals

[Transistor-Transistor]

Q3 is supposed to be a clean boost. Theoretically I'm thinking I could just bypass that stage and it would be normal. That may be my best move because the output volume of my device is insane. Unity is at around 8 o'clock

[Transistor-Transistor]

I just bypassed the Q3 circuit and went straight from C13 to R12 and it sounds perfect. I must not have had the Q3 circuit on the breadboard.

[antonis]

For more context on why I can't change any values, I built the original on the breadboard and it sounded good and normal so I made the schematic and tested everything and bought enough parts from Tayda to make 11 pedals

If so, something gone wrong during breadboard -> schematic transportation..

Anyway, I agree with Q3 stage delete..