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Projects => IC-based Overdrive => Topic started by: AndrewH on January 30, 2009, 10:55:10 AM

Title: vero board and bypass problems...
Post by: AndrewH on January 30, 2009, 10:55:10 AM
Hey guys, so I built this effect, it worked great...I  built one on vero board, it worked great too.

I then tried to add a bypass with a DPDT switch (just a standard bypass, not millenium) and the problems started.
The signal still gets through, and the bypass works, however there is a high pitched hum, even when bypassed, what's more, this hum increases when the gain pot is adjusted, even when bypassed.

if I touch, or earth the output (or the lug on the gain pot) the hum disappears.

I think that what is happening is that some of the signal is going back into the circuit and not the output? is this likely? should I then include a large resistor at the output of my circuit, into the bypass? is this a buffered bypass?

Has anyone encountered this problem?

I have made some adjustments to the components in the list, but I doubt these would cause such a problem.

I replaced the 1n914 diodes with 1n4148's
aslo, C2 is a 0,1uF, c3 is 27pF, c5 is 3,3nF

thanks guys.
Title: Re: vero board and bypass problems...
Post by: The French connection on January 30, 2009, 01:15:54 PM
Hi Andrew! Is it boxed? Are you talking of Vero (stripboard) or breadboard? It sounds like you have a ground issue...check your wiring and watch the debugging thread.

Good luck!

Dan
Title: Re: vero board and bypass problems...
Post by: AndrewH on February 01, 2009, 04:23:22 AM
nope, it's not yet boxed. I am talking about veroboard (strip board I suppose). I had built it on a bread board and then built another on the vero board. I am hoping it is a problem that goes away when I box it?
Title: Re: vero board and bypass problems...
Post by: cpnyc23 on February 01, 2009, 11:18:47 AM
My first thought is that you should chek your gain pot's ground connection for a cold solder joint.  Try reheating the connection and reflowing some new solder over the connection.  It sounds like the wire might be a little loose inside the solder.

-chris