Electro harmonix Enigma Qballs..any good?

[gradyclouse]

@paulbuzz - Great mods! What is the black wire attached to the "sleeve" contact on the expression pedal switch?

Edited Sunday at 19:27 by gradyclouse

[paulbuzz]

2 hours ago, gradyclouse said:

@paulbuzz - Great mods! What is the black wire attached to the "sleeve" contact on the expression pedal switch?

Wow, this really is The Thread That Would Not Die!

After this amount of time, I can't remember the answer to your question, and would need to take the pedal apart to be sure.
Looks as though it would be a switched connection to the board/circuit ground.
I think it might be the negative/switched connection to the 'expression socket active' LED?
Not certain though.

To be honest, if I had done these mods in any anticipation that people might be looking at them, I would probably have tried to do the whole thing much more neatly! 😳
But it does work well 🙂

[gradyclouse]

Thanks so much for responding so quickly. I hadn't noticed the LED. I guess another (last?) question is why three sets of wires from the TRS jack? I would think you just need to be able to close the switch/connection for each of the three poles (T,R,S) on the jack (to mimic the behavior when there is no TRS inserted)? It looks like you have three sets of wires connected to only two contacts per pole?

 

The reason I ask is I think you could implement this (absent the LED) by soldering directly to the exposed/top of the jacks as they are and not have to take the board out (lazy me

Edited Monday at 01:58 by gradyclouse

[paulbuzz]

2 hours ago, gradyclouse said:

Thanks so much for responding so quickly. I hadn't noticed the LED. I guess another (last?) question is why three sets of wires from the TRS jack? I would think you just need to be able to close the switch/connection for each of the three poles (T,R,S) on the jack (to mimic the behavior when there is no TRS inserted)? It looks like you have three sets of wires connected to only two contacts per pole?

 

The reason I ask is I think you could implement this (absent the LED) by soldering directly to the exposed/top of the jacks as they are and not have to take the board out (lazy me

Ermm... it's a long time since I thought about and did these mods, so it's possible that I might spout absolute nonsense here, but I think I've got it right...

 - In the pedal's original form:
       Without an exp jack plugged in, the normalising contacts on the socket feed the control signal from the envelope trigger to the filter's control input (TRS = control voltage/5v/0v)
       So: when a plug is inserted into the exp socket, the signal from the envelope trigger is disconnected, and the filter gets its control signal from whatever appears on the TRS plug that's plugged into the socket.
       ie: the switching between envelope control of the filter and external expression control of the filter is handled by the normalising contacts of the exp socket.

What I wanted was to be able to footswitch between envelope control of the filter, and external expression control of the filter, without needing to unplug/replug the external expression pedal from the socket.
So, what I needed to do was:

1) Remove the exp socket from the main pcb. I removed the socket whole, and re-used it. This was a bit tricky, but manageable if your desoldering skills are ok.
   The alternative would be to carefully dismantle/destroy the socket in place until just the legs are left, remove them one by one, and use a similar replacement socket. 
   So, the six pads on the PCB that are now free of the exp socket represent the output of the pedal's envelope trigger circuit, and the input to the filter control circuit (3 contacts for each)

2) my new footswitch needs to be able to connect the 3 contacts of the filter control circuit (ie the PCB pads where the exp socket's Non-Breaking contacts previously were) to either:
     a) the 3 contacts of the envelope generator (ie the PCB pads where the exp socket's Breaking contacts previously were), or:
     b) the 3 contacts of the exp socket (using the Non-Breaking contacts) which will bring in the control signal from the external expression pedal

3) So  i) the 3 'common' poles of the 3PDT switch should go to the CV/5v/0v of the filter control circuit pads on the PCB
          ii) one set of 3 switched poles of the footswitch should go to the CV/5v/0v of the envelope generator signal pads on the PCB
         iii) the other set of 3 switched poles of the footswitch should go to the CV/5v/0v of the external expression pedal (via the Non-Breaking TRS contacts of the exp socket)

When replacing the exp socket in the pedal enclosure, I put it in upside-down relative to its previous orientation, to keep its contacts away from the newly-rewired PCB pads.

Reading this back, it sounds like a kinda complicated thing, but it's really not. I think this is just a bad way of explaining it!
Hope it may make some sense to you - ask me again if not!

I'll see if I can conjure up a diagram or two that might make it simpler to follow.
 

Edited Monday at 05:06 by paulbuzz

[paulbuzz]

I think this would be it, unless I've done something stupid!
 

[paulbuzz]

10 hours ago, gradyclouse said:

... I guess another (last?) question is why three sets of wires from the TRS jack? I would think you just need to be able to close the switch/connection for each of the three poles (T,R,S) on the jack (to mimic the behavior when there is no TRS inserted)? ...

 

The reason I ask is I think you could implement this (absent the LED) by soldering directly to the exposed/top of the jacks as they are and not have to take the board out (lazy me

Sorry, realised I didn't actually directly answer your question!

I think the reason you couldn't really do this is that you would essentially be connecting your two expression control pots simultaneously, in parallel.
This might initially seem like a good idea - you could then set the control pots as required to get any desired mixture of envelope and external expression control - nice idea, eh?
There's a  problem though: if you set one of them to maximum and the other to minimum, you would be shorting the 5v expression voltage directly to ground through the wipers of the two pots - bad!

With some tweaking to the circuit I'm sure this could be made to work, but it would require someone a bit more competent at electronics than me to figure it out 😄

[gradyclouse]

Thanks! I will digest...