Add a Dry Kill Switch to Earthquaker Devices Afterneath Mod

[BBBehring]

Hey,

I'm new to this Forum and first I want to say hello to everybody. 

As the title say, I would like to add a Dry Kill to the Earthquaker Devices Afterneath. Cause I want to use it as a Send/Return Effect on my Mixer for DJ Sets. On the Earthquaker Website they say "Mix: Blends the wet signal into the dry. Though it does not actually go full wet, it will gradually lower the clean level as you turn it clockwise and give the appearance of full wet.", but I can't buy the Pedal without being sure that I can add a fully Dry Kill Switch to the Pedal.

I think it's not that a big Deal to add this Switch, but I'm confused by the inside of the Effekt and this Mix Poti which does't kill the Dry Signal totally. Since I don't need the Bypass function, I don't care if it's not working anymore, when Kill Dry On.

For pictures inside the box click:
-> http://www.gitarrebass.de/wp-content/uploads/2016/03/Earthquaker-devices-Pedal-innnen.jpg
-> http://atomiumamps.tumblr.com/image/138619066331

I would be so happy if somebody could help me, because i think this Effect could fit very well with mixing Elektronic Music.

Thanks a Lot

Best Wishes

[antonis]

Enclosure has enough space for a switch, even for footswitch dimensions..

Without circuit diagramm is hard to say the way you could obtain that..

< Since I don't need the Bypass function, I don't care if it's not working anymore, when Kill Dry On >
Plz explain a little bit more..

[BBBehring]

Thank you for the answer! 

< Since I don't need the Bypass function, I don't care if it's not working anymore, when Kill Dry On >. I just wanted to say, that once switched to "kill the Dry Signal Mode", I don't need the true bypass function to work (the foot knob).

Do you now if there is any way to get a circuit diagram?

[slacker]

There will definitely be a way to do a dry kill, it might be as simple as disconnecting one of the lugs of the mix pot or there will probably be a resistor that can be removed to kill the dry. If you can't find a schematic you will need to trace out the circuit around the mix pot to figure out where to make the mod.

Welcome aboard

[BBBehring]

Ok I see... I will get one and then report back with a circuit diagram around the mix pot.

Thank you for your help!

[Marcos - Munky]

Since it's most SMD and you don't care about modding it, probably the easier way is to remove the mix pot and put a jumper between the pads where the mid lug and the wet lug were connected (the one next to the orange caps). This way you'll have max wet signal and no dry signal. I think this will do the job, and you can just remove the jumper and solder the pot again to get it back to stock if you need to.

[BBBehring]

You mean simply connect the mid lug and the wet lug and say the wet lug is the one next to the orange caps?

Cool I have never thought of this! Sounds like a really good idea! With the Jumper I could test whether its a "real Mix Poti" (means dry Signal on one contact, mix in the mid, wet on the other). When it is (means Jumper between dry lug and mid lug gives only dry and Jumper between wet and mid only gives only wet Signal) then I know which contact is the dry or wet, am I right? Then I could simply put a switch before the the Dry Signal reaches the Poti and I'm done, no?

Or do I have to fully unsolder the mix pot for this, before putting the Jumper?

In fact I'm pretty interested in modding it and understanding those circuits...

[Marcos - Munky]

Looking from the "front" of the pot, with lugs facing down, you have from left to right lugs 1, 2 and 3, being lug 2 the wiper. Now, take a look at this image:

The "size" of the resistive material between the wiper and a lug gives the resistence between them.

As you turn the pot counterclockwise, the "size" of the resistive material between the wiper and lug 1 gets smaller, and the "size" between the wiper and lug 3 gets bigger. So the resistance between the wiper and lug 1 gets smaller and resistance between the wiper and lug 3 gets bigger. If you turn the pot fully counterclockwise, you'll have a direct contact between the wiper and lug 1, and the full resistence between the wiper and lug 3. If you have, for example a 100K pot, you'll have direct contact between the wiper and lug 1 and 100K resistance between the wiper and lug 3.

At the middle (if the pot is linear), you have the exact "size" between the wiper and each lug. Using the same 100K pot as the example above, you'll have 50K between the wiper and each lugs 1 and 3.

As you turn the pot clockwise, the "size" of the resistive material between the wiper and lug 1 gets bigger, and the "size" between the wiper and lug 3 gets smaller. So the resistance between the wiper and lug 1 gets bigger and the resistance between the wiper and lug 3 gets smaller. If you turn the pot fully clockwise, you'll have a direct contact between the wiper and lug 3, and the full resistence between the wiper and lug 1. Using again the 100K pot as an exemple, you'll have direct contact between the wiper and lug 3 and 100K resistance between the wiper and lug 1.

You mean simply connect the mid lug and the wet lug and say the wet lug is the one next to the orange caps?

Cool I have never thought of this! Sounds like a really good idea! With the Jumper I could test whether its a "real Mix Poti" (means dry Signal on one contact, mix in the mid, wet on the other). When it is (means Jumper between dry lug and mid lug gives only dry and Jumper between wet and mid only gives only wet Signal) then I know which contact is the dry or wet, am I right?

I never saw this pedal in person, and I didn't watched any vireo reviews of it to see how the pots works. But quoting your first post, "(the mix pot) will gradually lower the clean level as you turn it clockwise and give the appearance of full wet", so you have the dry at fully counterclockwise (lug 1) and wet at fully clockwise (lug 3). The picture you posted shows the back of the pots. So, if looking from the front the mix pot is the lower right one, looking from the back it is the lower left one. The lug 3 is the right one looking from the front, and the left one looking from the back. So it's the one near the two orange caps.

What makes this pedal to don't have fully wet is exactly the resistence between the wiper and the lugs. If it uses a low resistence pot as the mixer (which it probably do), at fully clockwise you'll have no resistence between the wiper and wet and a low resistence between the wiper and dry. This low resistence is "high" enough to lower the amount of dry signal that is mixed but "low" enough to get a small dry signal mixed. Think about this: if you put a 1K resistor between your (clean) guitar and your amp, you will get some volume decrease but will still hear your guitar. But if you put a 1M resistor, probably no signal will gets through the resistor. Another suggestion is to change the pot to a higher value one, so you can still use it as a mixer but it will have fully dry at fully conterclockwise and fully wet at fully clockwise.

Then I could simply put a switch before the the Dry Signal reaches the Poti and I'm done, no? Or do I have to fully unsolder the mix pot for this, before putting the Jumper?

You have to remove the pot before putting the jumper. If you put the jumper without removing the pot, there will be still some dry signal getting trough the lower resistence like I said above. Also, if you add the "dry kill" switch and the pot is somewhere but fully clockwise, you will have some resistence between the wiper and wet signal, lowering it's volume. You will need to remove the pot anyway, because it's soldered directly to the board. Or cut some traces at the board, which may not be an easy task since it's a SMD board and may have some small traces.

My suggestions are to remove the pot and add the jumper or just change the pot to a higher value one, In my opinion, the best one is to change the pot, because it will keep it's original look and you'll still be able to use it with a guitar with dry and wet mixed (although you'll have less control of the dry/wet mix as you have with a low resistence pot).

[BBBehring]

Wow I'm pretty impressed by you guys and your will to help me! Thanks a lot! And thanks to you I already learned a lot and I hope other people reading this post, will do too.

Is there any way I could check, whether the mix pot is really working like this, without unsoldering the mix pot? I guess the only way is with a circuit diagram, right?

[antonis]

Is there any way I could check, whether the mix pot is really working like this, without unsoldering the mix pot? I guess the only way is with a circuit diagram, right?

Diagram should be the safer way..

It could have mixed signals out on wiper (signals "fight" each other - win is reverse propotional to their series resistance) or wiper to ground (win is straight propotional to their series resistance)