## Line6 DL4 Looper Switch Mod

A forum devoted to mod, tips and suggestions for upgrading and rehousing your VERY CHEAP commercial stompbox to near boutique excellence.

### Line6 DL4 Looper Switch Mod

Hey there!

I've done some research and found out that some pedal companies and modders offer services including installing a switch to the Line6 DL4 that automatically switches to the looper. Needless to say that this caught my attention. I immediately opened up my DL4, grabbed my DMM and put my thinking cap on. The logical idea would be o look at the rotary switch and see what are the conditions for the looper to be active. After a while I figured that the rotary has 5 terminals, 1 connected to ground and 5 which have variable values. So I started testing. The first thin I did was measure the resistances between each lug in each of the 16 settings, this showed me that the resistance between the lugs was either 0 (connected) or infinite (disconnected). The looper setting showed infinite resistance in every connection. So this was a bit hard to make out. Then it hit me: since one lug was connected to ground, the other four must give out voltages. Since theres 4 of the lugs which can give either a voltage or no voltage, so a 1 or a 0, that makes 2^4 = 16. Exactly the number of presets. So the leads went out to a multiplexer obviously. I then did the same thing, but read the voltages for each of the remaining 4 leads and made another chart. I decided to make the point where my DMM read 3,25V as a logic 1, and 0V as, obviously, a 0. After completing the chart I got a smile on my face. The looper preset was all 1's. So to access the looper remotely, my idea is to break the connection between the rotary and send out 3,25V to each of the MUX inputs, and to get out of looper mode, remove the 3,25V from the MUX inputs and return the original values from the rotary. However, since this requires breaking 4 tracks + an additional one for a LED which I'd like, a 4PDT is out of the question.

So my conundrum is the following: How to achieve this?
I was thinking maybe using a DPDT, set one row for the LED, and maybe use the other to control an array of BJT's to make the connection to the rotary, and when broken send the 3,25V which controls the BJT's to the MUX inputs directly? Would this work? I've already found a place to draw the 3,25V from, there's quite a few spots where it can be grabbed from.

PS: I did a thorough search for this which yielded no results. I'd like to be able to make a picture tutorial to get this done because I know there are other DIYers out there other than me who'd like to do this.
I apologize if this is in the wrong subforum or if this has been discussed and answered, but I didn't find anything like it
TubeOrgasmer

Posts: 32
Joined: 20 Sep 2009, 11:57
Has thanked: 5 times
Have thanks: 2 times

### Re: Line6 DL4 Looper Switch Mod

Solved it!

All of the rails going to the rotary are 3,25V, except for the one to ground. When all the +V pins are disconnected, you get looper mode. When you connect them back, you get normal operation. So all I did was get 4 2n3906's and wired them as switches for the rotary's terminals. Now all I need is to install a footswitch which will toggle gnd to the base of the 2n3906's, and an LED for it and there you have it. Instant looper mode. It's all on breadboard so far, I'll wire it up tomorrow and take pictures. I am so hyped right now, and there I was about to sell my DL4
TubeOrgasmer

Posts: 32
Joined: 20 Sep 2009, 11:57
Has thanked: 5 times
Have thanks: 2 times

### Re: Line6 DL4 Looper Switch Mod

Ehm... maybe I'm thinking wrong, but wouldn't disconnecting the GND lug of the switch activate looper mode? Cut a trace, wire both sides to a DPDT and wire up a led on the other half of the DPDT, done!

But it could be that I'm missing something...

Pruttelherrie
Solder Soldier

Posts: 238
Joined: 18 Feb 2011, 20:35
Location: The low lands
Has thanked: 48 times
Have thanks: 105 times

### Re: Line6 DL4 Looper Switch Mod

I think I tried that, not sure, and the whole thing didn't work altogether. Could be that I've also shorted something, but it was enough for me to abandon that option and go with my initial idea of switching the lanes.

In the end I used a CMOS switching chip, a CD4016 which is basically a quad SPST to make or break the connections. Wasn't hard to implement and seemed like the best solution at the moment. Also, given that the enable pin uses +V or ground, it was easy to add an LED with the use of a SPDT footswitch.

Case closed I guess
TubeOrgasmer

Posts: 32
Joined: 20 Sep 2009, 11:57
Has thanked: 5 times
Have thanks: 2 times

### Re: Line6 DL4 Looper Switch Mod

It seems like Pruttelherrie is right:
http://www.thegearpage.net/board/showth ... ?t=1019908

I'll give it a try...
loylo

Posts: 65
Joined: 23 Jun 2011, 09:05
Has thanked: 15 times
Have thanks: 17 times

### Who is online

Users browsing this forum: Steeler [Crawler] and 5 guests