SPDT or DPDT Switching advice

[geohewitt]

Hey guys, I wanted to add a mod to a DS-1 I recently got where I switch from the stock values for R13 & C8 to my own values with higher gain. I understand on a schematic level what I want to do, but not sure what type of switch I would need for this mod, and also unsure of how I would wire it into the board. Here's a link to what I want to do, and i've circled R13 & C8 on the schematic 







Thanks!

Also: Aware the pcb is SUPER dirty, will clean up all flux residue and dirt to make sure there are no unwanted solder bridges.

[Alex83tele]

I wasn't able to load the images, but there are probably necessary components in between R13 and C8 so it would be DPDT. Each component getting their own pole with the original parts on one throw, and the new ones on the other. Sorry, I can't be more specific without being able to load the images. If you still looking for an answer later, upload the images to the forum, and I'll check back in. But I'm sure someone will be able to help you before then.


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[rutabaga bob]

Welcome aboard!   

[geohewitt]

I wasn't able to load the images, but there are probably necessary components in between R13 and C8 so it would be DPDT. Each component getting their own pole with the original parts on one throw, and the new ones on the other. Sorry, I can't be more specific without being able to load the images. If you still looking for an answer later, upload the images to the forum, and I'll check back in. But I'm sure someone will be able to help you before then.


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Ahh I posted links from imgur I cant find a way to upload files to my post :/

[geohewitt]

Welcome aboard!   

Thanks man!

[Rixen]

Click 'insert image' on the bottom left of the toolbar, above the smiley, then put your link between the two '[ img]' ' [/img]' things. Imgur also has a set of different link types for forums, reddit etc. You can use that function by copying the whole link with the [ img] parts, and inserting it in your text..
oh, and resize to a smaller image in imgur.

[geohewitt]

Click 'insert image' on the bottom left of the toolbar, above the smiley, then put your link between the two '[ img]' ' [/img]' things. Imgur also has a set of different link types for forums, reddit etc. You can use that function by copying the whole link with the [ img] parts, and inserting it in your text..
oh, and resize to a smaller image in imgur.

Okay sweet! Thanks man, think I fixed it

[amptramp]

Your schematic looks OK but beware that as the switch goes from one side to the other, it will go rapidly through a disconnected state where you might get a switch pop as C8 charges up to Vcc/2, the 4.5 volt supply.  Some people put a high-value resistor from the switch pole to each side to keep the capacitor charged.  If you never switch or you switch only between songs, this would probably not be necessary.

[Transmogrifox]

oh, and resize to a smaller image in imgur.

Sorry to pull this back OT, but here's another trick:

Code Select Expand

[img width=800]http://link.to.img[/img]

I find 800 px is usually good for most, but change that number to whatever size you think looks best in the forum.

Either way it's a less painful way to resize an image than having to go resize the source image.

[Hatredman]

I wasn't able to load the images, but there are probably necessary components in between R13 and C8 so it would be DPDT. Each component getting their own pole with the original parts on one throw, and the new ones on the other. Sorry, I can't be more specific without being able to load the images. If you still looking for an answer later, upload the images to the forum, and I'll check back in. But I'm sure someone will be able to help you before then.


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Not in this case. Both components are in series, so an SPDT is enough.


Enviado do olho da rua da amargura.

[geohewitt]

Had also posted this on reddit and got this response:
"It really depends how much room you have in the enclosure. I would add a second tiny PCB of proto board. You'll only need enough for the two resistors and caps. Desolder and remove R13 and C8 from the board. Add a wire from the first pad of R13 to the middle lug of a SPDT On-On toggle switch. Then a a wire from outer lugs of the switch to the proto board. One of those connections will go through one pair of resistor and capacitor, the other will go through the others. The last pad of the capacitors can be connected together, then take a wire from that connection back to the second pad of C8 on the main PCB."

So that solves my question, not sure why or when to use an SPDT versus a DPDT (but I guess that's a different question), but thanks anyway for the advice guys!

[PRR]

> beware that as the switch goes from one side to the other, it will go rapidly through a disconnected state.... put a high-value resistor from the switch pole to each side to keep the capacitor charged.



As for SPDT vs DPDT -- here you only need single pole. However by the time you buy the handle and the nub and the nuts and the body, another pole is sometimes no big expense. Since other circuits do need double poles, some techs prefer to stock a bag of DPDT.

[geohewitt]

> beware that as the switch goes from one side to the other, it will go rapidly through a disconnected state.... put a high-value resistor from the switch pole to each side to keep the capacitor charged.



As for SPDT vs DPDT -- here you only need single pole. However by the time you buy the handle and the nub and the nuts and the body, another pole is sometimes no big expense. Since other circuits do need double poles, some techs prefer to stock a bag of DPDT.

Cool man! In what case would you be needing a double pole switch? Sorry for the noob question, but from what i've understood don't they just act the same way as an SPDT but just have more poles?

[jez79]

Two poles switch two things at once
With a dpdt, you could dedicate one pole to the cap/resistor choice, and the second pole to an indicator led for example.
If you had parts in different parts of the circuit you wanted to change (instead of two in series as in this case), then a dpdt could swap two unconnected parts (as the first reply poster suggested)

[geohewitt]

Two poles switch two things at once
With a dpdt, you could dedicate one pole to the cap/resistor choice, and the second pole to an indicator led for example.
If you had parts in different parts of the circuit you wanted to change (instead of two in series as in this case), then a dpdt could swap two unconnected parts (as the first reply poster suggested)

Ohhh okay I gotcha, thanks man!


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[Alex83tele]

Not in this case. Both components are in series, so an SPDT is enough.


Enviado do olho da rua da amargura.

Sorry I didn't follow up on this thread. The app wasn't working, but it looks like you got your question answered, more or less.

As far as when to use single/double pole switches, don't overthink it. It's really simple. You could get the same result tethering the actuator arm of two spst switches together, as a dpdt. And three spst's for a 3pdt. It's so common for a device to require 2 or 3 circuits to change with the same action, that it has become common place to have switches with multiple poles. Otherwise, the effect that the indicator LED has on the circuit would have to be factored in, which is far more complicated than just putting it in its own circuit. Here's an image that might help.
It's really just two switches connected to the same lever. You might have figured this out already, but I thought, better late than never.



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