EMP noise in timers

[newfish]

Hi all,

Further to my '555' experiments, I've discovered that the ticking on my circuit is down to a very large EMP as the timer (7555) flicks between states.

Short of either building a Faraday Cage around said IC, or having lots of space between the audio and 'pulse' sections, is there anything else I can do to get rid of the 'tick' created?

Maybe boosting the audio as it comes into the pedal would improve the Signal to Noise ratio?

[oskar]

1. Scale frequency setting components. Make cap smaller and resistor larger.
2. Isolate timer ( v+ ) from the rest of the circuit with an R/C filter... say 100R/ 10uF.
3. http://en.wikipedia.org/wiki/Electromagnetic_pulse     

[Paul Perry (Frostwave)]

The power rail to the 7555 should go straight to the power supply input, so should the power rail to the rest of the circuit. 9so there is no conductor in common between the two parts of the circuit, except where the power comes in.)
And the same for the ground wiring.

i don't think it is a magnetic pulse that is the problem.
i think it is the + rail, or ground, or both, jumping when the switching occurs.
i shudder to think how it would be, if you had a regular 555!