Can't get unity gain through fx loop

Quad Cortex
1

After playing with the presets for a while I’m diving into creating my own and running into issues with the fx loop blocks. I have and ML10X loop switcher with stereo in and out, so I’m using both send/return pairs.

However, for this test, I’m running just a straight up patch cable from send 1 to return 1 and send 2 to return 2, to eliminate there being too many variables at play while I get the hang of this. I measured the patch cables for continuity and resistance to make sure they were in tip top shape.

I just can’t get the same signal when I engage the loop with nothing in it but a 10cm patch cable, as without engaging it. No matter how I set the snd and rtn levels on the fx loop 1/2 block I either get a much lower signal or a clipped signal.

I’m running a single lane through a clean amp, fx loop 1/2 block, cab to output 1/2.

Why is unity not just at 0? What am I doing wrong? The only way I’m getting close to not clipping at the same level as the block disengaged is to go somewhere around -7db on the send level, and then pump the return level WAY up.

EDIT: Just to clarify, the main issue is that snd+rtn 2 just seems to not be working correctly, I get almost no signal through just a cable from one to the other. The secondary issue is the clipping when bringing snd+rtn 1, or snd+rtn 1/2 to unity.

2

The fx loops actually boost the signal. People on the forum have measured the amount. I searched for the post just now- “Send Output is 4.5db louder than unity gain when using a TS cable.”

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Yes but what I’m saying is that I can’t even it out with the send and return level controls without clipping. Especially on loop 2, the level drop there is massive.

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Just stating what the normal behavior of the fx loop is. Seems like you have a hardware issue with the QC that their support would need to fix

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Gotcha, yeah it does sound like a hardware issue, I was just hoping I was making some kind of noob error…

6

Yeah, I feel like usually that’s the scenario when people are posting about the stuff on here. But seems like you have been good with trying to troubleshoot it correctly. But maybe someone else has an idea.

I was just setting up my QC in a new board and was revisiting the fx loop boost issue. Thankfully haven’t ever had it drop the signal super low

7

Turns out I had my PSU set to the wrong voltage and was underpowering the unit, which caused this issue.

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8

Thanks for the update! Glad you got it sorted!

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