Mark V 25 Effect Loop Issue

[strat68]

I can’t get the effect loop to pass a signal any longer. The cables work as loopbacks. If I run the guitar directly into the effects and output directly to the amp, that works. But running them through the effect loop won’t work. I’m out of ideas. This used to work.

 

[bandit2013]

I am not all that familiar with the Mark V:25 so I had to read the manual first. I see it is a dedicated FX loop so when ever a cable is inserted into the send and return jacks, the internal connection is broken and signal must coupled through a bypass cable or through an effects device.

You either have one of four issues.

1. The cable you plugged into the send or return is not making good contact to the tip of the plug inside the jack on the amp, or at the FX unit. Something could be inside the jack preventing good connections. Things like spiders find those small 1/4 jacks to be nice homes if they were left open for a while. If you have cables plugged into the jacks, that is not the case then. More than often, it is not having the cables pushed all the way into the jacks of the FX loop or the FX device.
2. The send/return is connected backwards on the fx unit.
3. bad cable, internal short. I have seen some poorly made cables in my day, wire not stripped properly and has frayed or loose wires. Depending on the amount of stress placed on the cable, any bending can translate into movement of the frayed wires to make contact to the shield. Also ended on rolling a 412 cab over a plug end once, that damage the plug and it was a permanent short.
4. bad cable, open circuit/broken wire. That I have come across as well. Bad solder joint or broken wire.

You stated the cables were used as loopbacks, I assume you mean you tested them in the FX send/return jacks to confirm they work?

 

[strat68]

I am not all that familiar with the Mark V:25 so I had to read the manual first. I see it is a dedicated FX loop so when ever a cable is inserted into the send and return jacks, the internal connection is broken and signal must coupled through a bypass cable or through an effects device.

You either have one of four issues.

1. The cable you plugged into the send or return is not making good contact to the tip of the plug inside the jack on the amp, or at the FX unit. Something could be inside the jack preventing good connections. Things like spiders find those small 1/4 jacks to be nice homes if they were left open for a while. If you have cables plugged into the jacks, that is not the case then. More than often, it is not having the cables pushed all the way into the jacks of the FX loop or the FX device.
2. The send/return is connected backwards on the fx unit.
3. bad cable, internal short. I have seen some poorly made cables in my day, wire not stripped properly and has frayed or loose wires. Depending on the amount of stress placed on the cable, any bending can translate into movement of the frayed wires to make contact to the shield. Also ended on rolling a 412 cab over a plug end once, that damage the plug and it was a permanent short.
4. bad cable, open circuit/broken wire. That I have come across as well. Bad solder joint or broken wire.

You stated the cables were used as loopbacks, I assume you mean you tested them in the FX send/return jacks to confirm they work?

Thanks for the reply Bandit. I spent some time and figured out that having a cble plugged itinto the stereo output of a Visual Sound H2O but not having it plugged in on the other end turns off the sound on the main output. That makes no sense as yet. My pedal setup is too complcated.

 

[bandit2013]

In most cases, some stereo units will treat the left channel as the primary channel and the other as a secondary. They are set up mostly for mono mode so if nothing is in the left channel the right will not do anything. I took a glance at the manual, a bit weird. This was for the square version. I see you can run the effect as mono input patching into the echo side, and the output (mono) or stereo on the chorus side, for the full effect with chorus or you can use the two fx separately and not cascade them. I would assume the input for the chorus has a disconnect switch so it can be used to bypass the echo side. Is that the only FX device you have in the loop? If you have others, try reducing the number of FX units in the loop to confirm it still works. You can narrow down what is causing issue after you simplify the number of FX units. I would start with one, and then add the others in. If the H2O is all you have in the loop, that could be most of the issue. That pedal should work if you plug into the chorus input and you should get chorus output (on the mono jack). Same could be said with the echo input and output. I do not have that pedal so I have no experience with it.