Please HELP! Sea Urchin - Clock noise when Mix pot maxxed!

[Ettore_M]

I built a Sea Urchin last year, and didn't have any problems. Today, I decided to change the footswitch, because sometimes it didn't work. Results were a locked PT2399 ( ), and after I changed it with a new one, I got clock noise in the circuit which it could be heard when the pot is maxxed! What could it be?? I tried two new PT2399s, but both behave the same. So, the problem must be in the circuit. But I didn't change anything other than the footswitch. I'm supposed to give it to a guy today who is interested in buying it, so I do need your help! Please!

Hector

[midwayfair]

It's the PT2399. They all do this. You can increase the filtering or just not turn it up all the way.

[Ettore_M]

It's the PT2399. They all do this. You can increase the filtering or just not turn it up all the way.

They all ALWAYS do this? So is it normal that this is happening? It didn't do it before. Sure thing. That's what is confusing me.
But how can I increase the filtering? A cap increase somewhere?
Thanks, BTW!

Hector

[madbean]

The PT2399s can vary wildly in terms of noise. I've pretty much come around to the idea that you really have to audition quite a few to find the lowest noise possible.

Like Jon said, increasing the filtering is another solution. For the SU, increase the value of either C11 or C12.

BTW: if your original PT2399 locked it should work again after a while. It doesn't usually result in a destroyed chip. Try grounding out all the pins to discharge any voltage remaining on the chip and put it back in.

[Ettore_M]

The PT2399s can vary wildly in terms of noise. I've pretty much come around to the idea that you really have to audition quite a few to find the lowest noise possible.

Like Jon said, increasing the filtering is another solution. For the SU, increase the value of either C11 or C12.

BTW: if your original PT2399 locked it should work again after a while. It doesn't usually result in a destroyed chip. Try grounding out all the pins to discharge any voltage remaining on the chip and put it back in.

Thanks for the reply, Brian! But I don't think the old one will work. I did what you told, and already left it for an hour or two. So, I'll go for the filtering. Is it supposed to alter the sound response of the circuit? Maybe it will be more "dark"? Or it will only affect the clock noise?
Thanks again!

Hector

[midwayfair]

Maybe it will be more "dark"? Or it will only affect the clock noise?
Thanks again!

Yes, it'll be darker, unfortunately.

You are talking about it only doing gurgling noises at the very far end of the time pot, right? And that's the only place? Or is there some other noise? The reason I'm asking is because ... do you use that setting often? Maybe you just didn't notice it before? That happens sometimes.

You can just swap out that 15nf cap for an 18nF and it'll probably have a minimal effect on the signal. Or change the pin 13 resistor for 12K.

[Ettore_M]

Maybe it will be more "dark"? Or it will only affect the clock noise?
Thanks again!

Yes, it'll be darker, unfortunately.

You are talking about it only doing gurgling noises at the very far end of the time pot, right? And that's the only place? Or is there some other noise? The reason I'm asking is because ... do you use that setting often? Maybe you just didn't notice it before? That happens sometimes.

You can just swap out that 15nf cap for an 18nF and it'll probably have a minimal effect on the signal. Or change the pin 13 resistor for 12K.

Thanks, Jon! Yes, at the last 1/8 of the Mix pot. And yes, it's possible not to remember it, but I'm pretty sure it wasn't there before.  I'll try the resistor first cause I don't have any 18n caps at the moment, and get back to you!

Hector