I’m using Quad Cortex in a rack on stage with midi control of preset and scene changes.
Cable length from Polytune tuner at my feet to QC is up to 10m. I think I have two options:
- Use a long jack to jack cable, making sure I buy a quality one with Neutrik jacks so they’re snug in the QC input 1. Tuner gives buffered output so unbalanced cable this long should be fine.
- Tuner into DI box at my feet, then balanced XLR cable to Quad Cortex. This has the benefit of we have tons of XLR cables, I can pick one the right length, or join a couple together as needed on different stages.
I assume phantom power from Quad Cortex input 1 could power an active DI box. You can only switch on phantom power when input is set to microphone rather than instrument. On the other hand, the tuner output is buffered so perhaps a passive DI box would work.
Is anyone using DI box - active or passive - for guitar input to Quad Cortex like this? Would be great to hear if others are doing this or what other people have tested before I buy a DI box, or I just buy a long cable…
10m = about 33 feet. Signals in unbalanced cables can degrade a lot after something like 20-21 feet. I would not advise option #1.
Option #2–tuner into a D.I. box, balanced XLR out to QC–is a far better option. I looked up how far 48V phantom power can reach in a cable and apparently it’s several hundred feet. If you want to use an active D.I. to run something like 10 meters, you should be fine using the QC to supply that.
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The way I use the Polytune is always in parallel to the signal chain driven directly from my wireless receiver (or guitar cable but that doesn’t happen very often these days anymore). The Polytune is on my pedalboard and just showing pitch «always on» and not affected by my signal chain mute. This way no signal degradation and you are free to use any any cable length (15m) works fine.
Maybe that helps.
Sorry, no answer (I agree with @DiffractionCircuit though) but I do have a question about how you mount/fix the QC to the rack?
I used to mount it to pedalboard with Velcro. Now I mount it on a fixed rack shelf with the same Velcro.
Fits fine a in 2u space on a 10" depth shelf. Power, usb and xlr out cables neatly zip tied. This way means I can quickly unplug and ease it off the Velcro if I want to use it outside the rack.
I looked into using a sliding rack shelf but it works fine on fixed shelf. Since I’m already using laptop for backing tracks, lyrics, midi control of quad cortex and mixer interface then no problem to also run Cortex Control on same laptop to see what is on QC screen and adjust any params.
Yeah this is what I’ll likely do. I was just curious what experience people had with active / passive DI into quad cortex and any gotchas they hit. I’ve ordered a mid range active DI to try so I’ll report back here.
Re length of jack cables. I think 30m would be ok because the tuner is buffered. Lots of other good reasons to use DI however.
I should have mentioned earlier that you would probably be OK with a passive D.I., but it looks like you have found your way forward. Cheers.