Friedman buxom boost

[Teddeeh]

No sound or anything. There is. A very low almost inaudible output. This is an unverified circuit.

[Alex]

Can you check voltages on pin 8 and 4 of the TL072? It should give you +9V & -9V.
If those are correct you should try using an audio probe.

[Teddeeh]

Pretend im an idiot, would i hook this up to the power so one lead to the 9v supply and then the pin and vica versa with the ground?

[PMowdes]

Take your meter, set it to test DC voltage (and if there is a range set it to something above 9v)

Connect the common (black) lead to a GND connection (battery / jack gnd/ board gnd)

Use the red lead to probe the parts of the circuit.  

If you look up the IC data sheet you'll see that certain pins are supposed to carry specific voltages (ie pin 4 > gnd (0V) and pin 8 > +Ve (9V).

If the voltages are off you can get an idea of where your problems lie.

[Alex]

That's the correct explanation.
In this case pin 4 (TL072) has to be -9V.

[Teddeeh]

Just doing that now... with the pin 4, do i reverse? I.e red in 9v and test pin 4 with ground? As you said minus...? Im confused.

[Teddeeh]

1 0.76
2 0.73
3 0.69
4 0.75
5 0.76
6 0.78
7 0.77
8 2.15

I know this looks wrong..

[PMowdes]

It does look wrong

What I'd suggest next is find a copy of the schematic, and use it to track the supply voltages and gnd through the vero, you should be able to do this with just the vero layout.

Pay attention to things like reference voltages, bias voltages etc and make sure that you have the correct voltages at the relevant ic  and transistors legs.

Once you have the correct voltages you should be on track, if it still doesn't work turn your attention to the signal path and follow it through from input to output.  You'll get the hang of it

[PMowdes]

looking at the layout and the schematic this is what I think should happen



Red is +9v, blue is -9v and black is GND.

GO through the vero with your meter and see if you get the correct voltages at the IC's (ignore the blue coming out of the base of the BC639 next to the 1054 IC)

[Teddeeh]

Thanks man, i rebuilt rather than debug. After strippin away the parts its not much left on the board. Built and it works. ALOT of volume/boost on tap but all works as it should. Many thanks.