TS808 first attempt

[PerroGrande]

Hey Lazer,

Just for kicks, try changing R7 from 51K down to 4K7 or 3K3 and see what that does...

[lazerphea]

Hmm okay so we're getting somewhere.  I don't know where but we're getting there...

Are the diodes facing in opposite directions as in the schem? 

Uhm... I just arranged them so that they are one the opposite the other... does the orientation matters???

[lazerphea]

Hey Lazer,

Just for kicks, try changing R7 from 51K down to 4K7 or 3K3 and see what that does...

Ok, I try it now!

[lazerphea]

You are Bread Boarding this right?

Yeah!

[lazerphea]

Hey Lazer,

Just for kicks, try changing R7 from 51K down to 4K7 or 3K3 and see what that does...

Nothing happens! :\

[PerroGrande]

When you say nothing happens -- does that mean nothing changed and the pedal is still effectively "clean", or that you don't have any sound at all?

[lazerphea]

When you say nothing happens -- does that mean nothing changed and the pedal is still effectively "clean", or that you don't have any sound at all?

The pedal is still clean....

[PerroGrande]

Okay --

If R6 (4K7) is not connected to either Vref or to ground, the pedal will do what you're experiencing.  You can build the screamer either way (the capacitor in series with the resistor allows this).  Some of RG's excellent articles show R6 connected to ground, while others show Vref.  Either is okay -- just as long as it is connected!

[Bensnap]

Make sure none of your components/leads are touching. I have C4 and R7 close to each other on the bead board and some times they touch and that makes it go clean.

[ayayay!]

Uhm... I just arranged them so that they are one the opposite the other... does the orientation matters???

Yes, very much so. 

[lazerphea]

Uhm... I just arranged them so that they are one the opposite the other... does the orientation matters???

Yes, very much so. 

Ok, I inverted them but nothing happens... I get always the same clean sound...

[Zben3129]

The higher the resistance, the more gain you will get. So raising the 51k to 500k or 1m might make a difference, rather than to 4k7.

Zach

[lazerphea]

The higher the resistance, the more gain you will get. So raising the 51k to 500k or 1m might make a difference, rather than to 4k7.

Zach

Tried with 1M resistor but nothing changes.

[lazerphea]

Guys, I go to bed now... I'm wasted and I'll continue my work tomorrow morning... for now thanks a lot for the support!!!

[PerroGrande]

It is never a bad idea to take a break when things aren't going as planned.  I've solved any number of "insurmountable" problems after some quality sleep.   

[George Giblet]

> How can I say if C4 is shorted?

Measure the resistance across the cap.  Anything less than an ohm is usually a short.

> put the black lead of my meter on pin 1 and the red one on pin 2 of the IC; what I read is:
3.25 Ohm if the 500K pot is in 500K position
2.99 Ohm if the 500K pot is in 0K position

Actually you have already got the measurement here.  The resistance seems awefully low.   The 51k pretty much eliminates the pot's effect  from these measurements and the diodes don't usually show such a small reading (I'm assuming you are using a digital meter?).

Look on the back of the board.  Make sure there are no solder bridges across pins 1 and 2 of the IC or across C4.

[lazerphea]

Ok guys,
It took me 2 hours or so, but here's my breadboard layout:



I know it's a disturbing mess, but I tried to use different wires' colors for clarity. I'm pretty sure I messed up something in the opamp's feedback loop...

[arma61]

Ciao

for the sake of clearness which transistors are you using ?

Armando

[lazerphea]

Ciao

for the sake of clearness which transistors are you using ?

Armando

Ciao Armando,
I'm using the 2SC1815, though I read "C18156R" on them..

[oskar]

R6 is going to the bus you call Vc.
Are you sure the bus is connected all the way? You may have to bridge it halfway. Have you secured continuity?