crybaby sweep mod Help wiring 6 position switch

[gigantor]

imageshack.com/i/polCC3Umj

imageshack.com/a/img921/5959/AfXdsT.jpg

I  hope these links work. I'm working on mods for my crybaby GCB-95 and i'm stuck working on the mod for the "sweep" capacitor.  I'm trying to add a 6 position switch with a different size capacitor on each position.  i understand how the switch works. Mine is a 2 pole 6 position, I understand i will only be using one pole and i checked continuity to confirm the lugs.  I've tried all i could to find an answer and no luck.

Adding wires from the circuit board where the .01 uf cap how do they connect to switch?

Also when i solder capacitors onto the lugs should i assume they are polarized and connect the pos to the lug? then bind the free end of all the capacitors and connect them back to the board?

I have to guess one wire will go from the board to the common lug then the capacitors will be soldered to a single wire and back to the board

also

I'm new at this, I've done a few mods already to my wah with success.  seems this might cause some  damage if things are not wired correctly? 

thanks for any help

[ashcatlt]

I think the plan you've got is reasonable. You could use both poles to switch both ends of the caps, but it would be kind of ugly. Pretty sure they're going to pop some either way, and I'm not sure there's a good solution to that.

I don't think those caps want to be polarized. None of them should be big enough that you need to use electros. I haven't really tried too hard to sort it out, but I don't think we can assume that one side of that cap is always going to be more positive than the other. It looks to me like they're both somewhere in the middle of the supply. () A meter might tell you.

[gigantor]

I i know there will be a pop, there is a solution although i can't remember off hand. so are you saying connect the capacitors one end to one pole and the other end to the other pole in the same position? I was just being extra careful about the polarity i think i know just enough to be dangerous right now. well thanks for the help much appreciated

[gigantor]

Oh wait it just clicked for me i can connect each wire from the board to it's own common lug then just connect the caps to each respective positiion for both lugs.  Is this the correct way of looking at it?

[col]

A couple of questions for others to answer:

1) Would a shorting type of rotary switch reduce/eliminate popping?

2) Which end (if any) of the cap would cause less of a pop when disconnected (hot or ground)?

And, gigantor: since it appears that you only require a 1-pole switch, is there any advantage for you to instead use a 12 position switch with 12 caps?

[ashcatlt]

Dec 29, 2016 22:36:54 GMT -5 col said:

A couple of questions for others to answer:

1) Would a shorting type of rotary switch reduce/eliminate popping?

Maybe, but probably not. It wants "pulldown" resistors to let the loose end bleed off charge while it's disconnected, but I don't know what happens to the rest of the circuit if you start sticking those things in.

2) Which end (if any) of the cap would cause less of a pop when disconnected (hot or ground)?

In this case, it's not really a hot/ground issue. These caps are in series with the signal, and shouldn't be polarized at all. Even in the case where one side is clearly more positive than the other, I don't think it matters which end gets switched.

[col]

Dec 29, 2016 22:48:19 GMT -5 ashcatlt said:

Dec 29, 2016 22:36:54 GMT -5 col said:

A couple of questions for others to answer:

1) Would a shorting type of rotary switch reduce/eliminate popping?

Maybe, but probably not. It wants "pulldown" resistors to let the loose end bleed off charge while it's disconnected, but I don't know what happens to the rest of the circuit if you start sticking those things in.

What I wondered is if by adding a second cap in parallel (by using a shorting-type rotary switch), would the signal bleed into the second cap (as the switch is rotated), and thus reduce/eliminate the popping problem? Of course, I could be (and probably am) way off.

2) Which end (if any) of the cap would cause less of a pop when disconnected (hot or ground)?

In this case, it's not really a hot/ground issue. These caps are in series with the signal, and shouldn't be polarized at all. Even in the case where one side is clearly more positive than the other, I don't think it matters which end gets switched.

I just mean the end nearer ground vs the end nearer hot. Again, I'm just asking questions from pretty-much total ignorance.

[reTrEaD]

Dec 29, 2016 13:22:50 GMT -5 ashcatlt said:

I think the plan you've got is reasonable. You could use both poles to switch both ends of the caps, but it would be kind of ugly.

Yeah, the idea of using lugs from each half of the switch is useful because you have places to connect the capacitors. But it gets kind of ugly since the end of each cap will be 180 degrees apart. The leads will all cross over each other in the middle. Maybe just thread some thin bare wire through all the lugs of the unused side of the switch? That will create a "common" bus for one end of the caps. Then it won't matter which lug the switch each cap connects to on THAT end.  That way the leads won't need to cross.

Dec 29, 2016 13:22:50 GMT -5 ashcatlt said:

Pretty sure they're going to pop some either way, and I'm not sure there's a good solution to that.

I don't think those caps want to be polarized. None of them should be big enough that you need to use electros. I haven't really tried too hard to sort it out, but I don't think we can assume that one side of that cap is always going to be more positive than the other. It looks to me like they're both somewhere in the middle of the supply. () A meter might tell you.

This looks like where gigantor is starting from. An R G Keen mod:


www.geofex.com/article_folders/wahpedl/wahped.htm#mods

And I think you're right. One end of the cap will be more positive than the other.
Q2 is an emitter follower.  I would expect the emitter of Q2 to be biased somewhere near 1/2 the supply.
The other end of the cap will be somewhere around a volt to maybe a volt and a half.

With that in mind, I think we shouldn't try to bleed the voltage from the caps when they're disconnected.  Rather, we should try to maintain it.  Maybe large value resistors (something in the range of 1~10 meg) between each throw of the switch and the pole.  I reckon we'll see a rather large signal on that emitter resistor.  So we're still prone to popping when we change the cap.  We don't know exactly where we'll be at the moment when the cap is changed.  And since the resistors we're using will be necessarily large, each cap won't follow the signal closely.  But at least the DC component is handled.

Dec 30, 2016 17:00:54 GMT -5 col said:

What I wondered is if by adding a second cap in parallel (by using a shorting-type rotary switch), would the signal bleed into the second cap (as the switch is rotated), and thus reduce/eliminate the popping problem? Of course, I could be (and probably am) way off.

Yes. A make-before-break switch would be preferred here. It won't eliminate the residual popping that's likely to occur even with the biasing resistors. But it would definitely mitigate it to some degree.

[col]

Dec 31, 2016 6:03:49 GMT -5 reTrEaD said:

Dec 29, 2016 13:22:50 GMT -5 ashcatlt said:

Dec 30, 2016 17:00:54 GMT -5 col said:

What I wondered is if by adding a second cap in parallel (by using a shorting-type rotary switch), would the signal bleed into the second cap (as the switch is rotated), and thus reduce/eliminate the popping problem? Of course, I could be (and probably am) way off.

Yes. A make-before-break switch would be preferred here. It won't eliminate the residual popping that's likely to occur even with the biasing resistors. But it would definitely mitigate it to some degree.

Of course, 'make-before-break' is what I meant to write - brain fart. As I was writing 'shorting-type' (in two separate posts no less), I knew I was using the wrong phrase but could not put my finger on the correct one. Anyway, you seemed to get the gist of what I was aiming at.