(works without power but not with) changed to how do i build upon this circuit

[no1]

gday, very new, decided to breadboard up a circuit after my mate told me how simple some pedals are.



both work passively but when i connect the red lead of variable power supply to the points labelled +9v and the black to the ground circuits, i get no sound?

[exztinct01]

please post image of your breadboarded circuit

[Cozybuilder]

Did you try this with a 9V battery?
Is your power supply AC or DC?

[no1]

i would of tried a battery but i dont have one about atm

[duck_arse]

welcome to the forum, no1, are you another cobber?

your bottom right red wire appears to connect to the outer buss strip, with nothing else connected to that strip. is this correct, cause it ain't right. what transistors are you using, and do you own a multimeter? you will need one to answer all out questions from here on in.

[no1]

i am indeed another aussie, but i had to look up the word cobber to be sure that's what you meant ;p

it just appears that way in the photo due to the solder connecting to the bit of wire to the post leaning over.

i do have a multimeter..ive already checked the continuity of most of it and found a few mistakes earlier that were rectified and i replaced one of my guitar cables that was faulty.
Ive checked the transistors with the multimeter setting, im confident they are working (is it normal to have to remove them from the circuit to test them?). They are general purpose 2n3904's..There is noticable gain through my crappy little bucklay BA-5G without power applied and absolutley nothing with power applied and volume and gain all the way up. i just checked the Di (focusrite) with power applied and i could turn the volume up all the way and only notice some noise.

i did change some values that i dont have atm, maybe one is volume or something and maybe i changed the same one on the easy drive earlier..

[samhay]

Try connecting the output capacitor (I assume you have an output capacitor?) from the other side of R3 (i.e. from collector of Q2).

[no1]

i forgot the output capacitor but didnt make any difference..i also had the 100k resistor between the transitors also wrong..fixed..no difference
i just tried a 9v battery, got same result...so its not the power supply
putting the output to the collector has same result.

[thermionix]

Sorry, but are you trying to drive a speaker with this?

[PRR]

> the actual circuit i've made now.

I suspect your R1 is about 3 times smaller than usual, and R3 is about twice the usual size.

We normally scale things so around-the-loop R3 drops about half of supply voltage. With your larger value a R3 I think you will find that R3 is pulled-down nearly to zero, or actually to the top of R2, leaving dead-zero across Q2.

If you can find another 10K, put it in parallel at R3.

If you find several, series some for R1 to get 20 or 30 K ohms.

Your goal is to find Q2 collector "about half" the supply voltage. The exact value is not critical for "it works". The exact value may give some variation of overload quality. But the first thing is to get Q2 collector "in the middle", not slammed to zero or 9V.

[no1]

thanks for the reply but i think im giving up on that circuit..im on to my 3rd and it works well



how would i go about adding a 2nd and 3rd transistor to this circuit?

[Vinnie500]

Sometimes you just have to move on for your own sanity, but I also find getting things to work that didn't use to work can be the most educational and satisfying.
Having said that I can actually feel the nasty looks I get from my debugging pile, it haunts me.