"Making" a 3pdt switch using relays?

[DanielWong]

I've never heard anyone recommend this idea andI just though it up...will connecting a dpdt footswitch to a 3pdt relay work well for a #pdt footswitch substitute?

[cloudscapes]

it works, but its one more mechanical component that can fail. it also sucks up a fair amount of juice so I wouldn't use it with batteries.

[The Tone God]

I've never heard anyone recommend this idea andI just though it up...will connecting a dpdt footswitch to a 3pdt relay work well for a #pdt footswitch substitute?

Why are you using a DPDT switch to control a relay in the end gaining only one more pole ? It could be done with simpler switches. And if this is for bypassing why a 3PDT relay ? All you would need is DPDT.

Oh and I take it you didn't follow my advice about reading ALL of GEO did you ?

it works, but its one more mechanical component that can fail. it also sucks up a fair amount of juice so I wouldn't use it with batteries.

One could use latching relays so current usage occurs only during the switching cycle. There are lower current relays that would be fine for most battery usage.

Andrew

[DanielWong]

Well, I wanted to make it true bypass and have an LED...

I'm sorry about reading all of GEO...I tried, it's just too hard...

[The Tone God]

Well, I wanted to make it true bypass and have an LED...

Usually from the control logic needed for the relay you can derive the state and drive an LED without needing another pole or in worst case you can use a mill. type indicator. The reason I'm suggesting this is that 3PDT relays are tougher to find and more expensive then DPDT.

I'm sorry about reading all of GEO...I tried, it's just too hard...

Unfortunately many of the questions you are asking are answered there so you should give it a shot before posting here. The function is also your friend as this topic and many others have been discussed before.

As for what to read at Geo how about this:

http://www.geofex.com/Article_Folders/relays/relays_for_switching_audio_signa.htm
http://www.geofex.com/FX_images/relays2.gif

Andrew

[KMS]

Okaaaaaaaaay!

I have done this....actually I made a 6PDT using two 4PDT latching relays along with a SPDT MOM. These are the micro relays needing at least 5VDC and not more then 9VDC which also have 1amp contacts.

Now if you try this with some other types of relays (which I have experimented with a lot) you will find out why I made the choice for the relays described above (I would tell you but I don't have time to write a book).

One draw back to latching relays (or any relay); when you activate the relay it will cause a very noticeable drop in power for any other circuits running with a common power supply.  This causes unpleasant sounds coming out of your guitar amp momentarily.  Also once the power feeding the latching coil (or any coil) is cut you get a negative power spike in the circuit, which must be rectified or you blow things up, damage components and also have more unpleasant noise coming out of your guitar amp.  

RG has a nice write up on this but to have a full understanding of his work you must know a little physics and have a little experience under you belt; however; I think he shows how to wire the diode to rectify the negative power spike (not to hard to figure out).

SOOOOOOOOOOOOO......you need a separate power supply for your relay and then another for you audio circuit and you need to rectify the relay because you have a common ground with both power supplies and the negative spike will find the common ground.

So......I bet this is a little more than you planned on?