LED to channel switcher

[j_wyatt]

Hello, all:

I signed up for this forum a few years ago when building a mini-booster and have recently gotten back into tinkering with things.  I'm actually grappling with a couple of issues right now but I'll start with the one that seems simplest.

I have a channel switcher for my amp that does not have an led (came with the amp from the company who built the amp) and sometimes during high sound pressure levels while playing if I am switching back and forth it is difficult to determine which channel I am on especially when I have the "dirty" channel set with low gain.  With the sound blowing past me, I cannot tell, but I am certain the tonal difference is noticeable out front.  Anyway...I thought I'd embark on installing and LED to help with that situation.  I wired it up as a typical on/off switch should be and when switching the LED does, in fact, come on and off...that is until I plug the cable into the amp.

It is a tip/ring/sleeve quarter inch and the box shares a second switch for turning off and on the reverb.  I am not concerned about an LED for the reverb...just indicating between the clean and dirty.

I surmise the problem is that the switch really acts as an "on/on" because is switches between two channels but whichever channel is on is "on".  If that makes sense.  By plugging the cable in, a kind of loop is created causing the LED to stay on all the time.

I've tried about every configuration I can think of and feel the solution is probably simple (maybe a diode?) and appreciate any advice offered.

Rock on,
Jason

[Ripthorn]

One thing that would work is a bi-color LED if your switch is on-on.  Other than that, I am not familiar enough with the innards of footswitches and amps to know what it is doing.

[oskar]

Which amp?
Which switch?
The LED worked with the switch not plugged in??? So obviously there is a battery in the switch... None of mine had that so I'm not sure I can help here...

[j_wyatt]

It is an FS22 from Carvin.  I installed the battery as part of my venture.  I neglected to mention that in my post.  That's the funny thing.  If I don't plug the cable into the back of the amp, the LED with come on and off.

[oskar]

https://www.carvin.com/manuals/fs22_to_fs36_mod.pdf

[j_wyatt]

Awesome! Thanks, Oskar.  Though I won't be adding an additional switch I see the principle.  I guess I should take another look around Carvin's site...didn't know they offered such things.

[oskar]

You're welcome... I googled and this was my first hit. Then I checked the carvin page and turned up with nothing at all...    A bit too much information there perhaps...



oskar

[j_wyatt]

I also just completed a build of the AMZ mosfet boost and am trouble shooting what's going on with that.  I've checked and triple checked all the connections, etc., with no luck.  I cannot display the schematics given to me when I purchased the board per request of Mr. Orman.  He provided a true-bypass diagram for switching with LED that I used for building his mini boster a few years ago that worked for me. 

One of the things that is different with the mosfet boost, though, is it has a gain output that is to be wired to the pot along with an output lug I assume goes to the pot as well.  The LED comes on dim at first then hits full power.  When plugging in the box, I get a very faint signal when the effect is on but it bypasses properly when off.  I should probably post it as separate.

Got to head out the door...thanks again.

[oskar]

Yes. Make your AMZ boost problem a separate post and add voltages...
http://www.diystompboxes.com/smfforum/index.php?topic=29816.0

[j_wyatt]

By the way...thanks Brian...not a bad idea to try.  I assume we're talking on/on but I'm not sure.

[oskar]

A comment on the schematic/mod
As I see it you either use a spdt ( is that what the provided switch is? ) or install a dpdt in wich case you drive the LED from your own battery and connect the battery minus to ground.
The reverb is set up in a different manner with some sort of inverted function where the switch instead bypasses the LED.

[j_wyatt]

It could be a spdt but Ive never seen one built the way these look and I haven't been able to find any information on what switch Carvin uses.  I was just thinking that I could wire a dpdt somehow so when the switch is hit, the signal is divided and might solve the problem.  I think I will try a dpdt as you state in your post.  I have tried every possible configuration with the proided switch and cannot get satisfactory results.  I happen to have a dpdt and will experiement and let you know the result.  Thanks for working so hard on a solution.

[j_wyatt]

 SOLUTION: I installed a dpdt switch in place of the provided switch in the FS22. 

       1   4
       2   5
       3   6

1: nothing
2: Red wire from 9v
3: + to LED
4: Tie to solid ground wire
5: Black wire to cable
6: nothing

I use a Carvin Vintage 33 amp.  I chose to wire it this way which with illuminate the LED on channel one (clean).  I did so because I use the clean channel much less often and decided this would be a good way to save battery life.  If the opposite is desired, simply invert the wiring.  I also tied the negative lead from the LED and the negative black wire from the battery clip to the solid ground wire.