@Rolbista:
I'm not sure what you mean by "taken directly from the speaker cable". You mean a cable connected directly to the two leads of the speaker while it is active...? Or from the board after the speaker has been removed? The 8 ohm resistor to ground can be helpful and sometimes a limiter resistor in series will help too. The output to the speaker must be hot enough to drive a speaker. That is a lot more signal than a guitar puts out so this will commonly cause problems with certain un-buffered pedals (which distortion pedals often are. Try taking the signal out BEFORE the transistor. This will give you the pre-amplified signal which might be the perfect level for your fuzz.