What kind of switch 9/18 volt?

[idsnowdog]

I tried to add a three-pole switch to the phantom power box that I built but I wasn't able to make it work. What kind of switch would I need to add to this schematic to be able to switch between 9v and 18v?

 

[PFDarkside]

Just a DPDT switch.

I can do a quick diagram tonight if someone doesn’t jump right in and do it.

Actually here’s one, although I think you need a link between the bottom two switch pins.

 

[nexion218]

I had a thread about this sometime this year, ArtieToo gave a perfect diagram for this, but for some reason I cannot find it. If I recall well, there needs to be a jumper somewhere like PFDarkside said.

Also, be VERY careful with the polarity of your current! I wired up the switch correctly it was perfectly switching between 9 and 18 volts and when I measured it, I did not pay attention to the polarity. I wired up the guitar, connected the EMGs and the moment I plugged in my cable a perfectly working set of 81/85 was fried... They basically "reverted" to passives and had quite a vintage sound without all the preamp stuff ..

(Just to be clear, I wanted it to switch the current fed to the EMGs in my guitar not a phantm power box, but from an electrical/switching point of view it's the same thing).

EDIT: Found the thread!

https://forum.seymourduncan.com/forum/the-pickup-lounge/336019-help-with-push-pull-wiring

 

[idsnowdog]

Like Artie, I thought there would need to be a jumper across the bottom poles.

 

[Artie]

Yes. There does.

 

[idsnowdog]

I will need to find a new project box because there isn't enough room for the switch. Thanks for the diagrams to all.

 

[idsnowdog]

I was able to use this diagram with the three-pole switch I have and it works. So I won't need a larger project case.

http://s3-eu-west-1.amazonaws.com/p...ring.png.682c8d476139c08e5a309d51429b1465.png

 

[Artie]

That's simple and clever, but it does have one teensy consideration. And I'm probably being anal here. But if you happened to play on one battery for a long time, then switched to two, the stronger battery would try to recharge the weaker one. Not good with alkalines. I'm probably over-thinking it, but still, something to be aware of.

 

[PFDarkside]

That's simple and clever, but it does have one teensy consideration. And I'm probably being anal here. But if you happened to play on one battery for a long time, then switched to two, the stronger battery would try to recharge the weaker one. Not good with alkalines. I'm probably over-thinking it, but still, something to be aware of.

I was just thinking battery life in general.

 

[Artie]

Yeah. I'm not sure how battery life would be impacted. I personally, have never done the 18 volt thing. Typically, even three active pups draw less than 1 milliamp. They're very thrifty.

 

[idsnowdog]

The only way to get past that would be to build dedicated boxes for each voltage.

 

[PFDarkside]

Yeah. I'm not sure how battery life would be impacted. I personally, have never done the 18 volt thing. Typically, even three active pups draw less than 1 milliamp. They're very thrifty.

In the above cases you are drawing in parallel for 9V, series for 18V so both batteries are drawing all the time. In the latest it just bypasses the second battery, so it’s only drawing at 18V but the primary is always drawing. As you say, probably no big deal. I get years on my EMG Guitar.

 

[idsnowdog]

I think uneven battery life is a theoretical problem at this point because I haven't seen a real-world effect. I first built my phantom box probably in 2005 and I believe I still have the original batteries in it. I tested them yesterday and they still read 8.5 volts.

 

[Artie]

I get years on my EMG Guitar.

I wish I did. I don't play my actives as often as my passives, and keep forgetting to unplug the plug. I usually notice the next evening.