6-position rotary switch wiring question...

[dehughes]

Hello again,

Is it necessary to place high value resistors between each of the positions on a 6-position rotary switch used to change plate cap values in an EF86 tonestack? I've created an EF86 channel that is a combination of AC30/4 and DC30 values, with a bit of '65 Amps London thrown in for good measure, and have noticed that only once did I experience a loud "POP" when switching between the positions. I thought that was going to be the case all the time, being as I have yet to wire in the 5.6M resistors I purchased for the switch, but in playing around with it just now the switch made no popping whatsoever when changing between the positions.

So, what should I do? Will it be a problem later? Are those resistors necessary?

[Noel Grassy]

Is your switch a "make-before-break"? If so, you've probably eliminated the pops and won't need those resistors. Any of the resident engineers wanna chime in here?

[krash]

i asked you this on the other forum too ... but what value caps are you using?

just curious.

might experiment with 6-pos myself.

[dehughes]

It is "break before make", as I thought that was what I was supposed to use....

So I assume I need the resistors, then.

[mhuss]

I don't think make-before-break helps in this situation, because it's the charge built up on the unconnected caps that causes the pops, and they will discharge with a pop when you make the connection with them, before or after breaking the previous connection.

--mark h

[dehughes]

I don't think make-before-break helps in this situation, because it's the charge built up on the unconnected caps that causes the pops, and they will discharge with a pop when you make the connection with them, before or after breaking the previous connection.

--mark h

Yeah, that makes sense. In speaking with others I determined I needed a break before make switch...though I'm not sure now. It really doesn't matter as I'm going to wire in the resistors anyway now.

Thanks!

[krash]

FWIW there's no reason you can't use 1/8W tiny resistors for this purpose, which makes it possible to wire them directly to the switch.

[mhuss]

For a given resistance value, smaller resistors produce more noise. But, I don't know that this is an issue at this point in the circuit.

--mark

[krash]

yeah these are just bleeder resistors. [virtually] no signal going through them during normal use.

[dehughes]

Cool. Thanks. I'd do that, but I've already purchased some 1/2w carbon comps....that's going to be tight. Oh well, if Matchless guys can do it, so can I!