# QC grounding hint **URL:** \ **Category:** Quad Cortex\ **Created:** [May 14, 2024, 9:43pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117 "2024-05-14T21:43:01Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![TieDyedDevil](https://sea2.discourse-cdn.com/flex020/user_avatar/unity.neuraldsp.com/tiedyeddevil/32/6455_2.png) [@TieDyedDevil](https://unity.neuraldsp.com/u/TieDyedDevil)\ **Post date:** [May 14, 2024, 9:43pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/1 "2024-05-14T21:43:01Z")
So you’ve turned on your QC while its output is connected to a live input. Bzzzzzzzz. Here’s how I’ve dealt with that. I assume that you’re sending one or both of the XLR outputs to a stage box or directly a mixer, and that at least one of the QC send outputs is unused. Plug a TRS-to-XLR cable from a QC send to an input on stage box/mixer. Turn that channel’s trim all the way down and mute the channel. How it works: the ground wire in the extra cable connects the signal ground in the QC to the signal ground in the mixer, which means there’s always a ground connection, even before the QC establishes its XLR output grounds during boot. ---
**Author:** ![elmaxel](https://avatars.discourse-cdn.com/v4/letter/e/ce7236/32.png) [@elmaxel](https://unity.neuraldsp.com/u/elmaxel)\ **Post date:** [May 14, 2024, 9:55pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/2 "2024-05-14T21:55:45Z")
My QC is connected at home to an active speaker via a TRS cable and i have a static hiss i cant get rid off too, already tried getting my powerline clean and all the stuff. Do you mean i have to use another mixer/speaker to get this effect? ---
**Author:** ![DiffractionCircuit](https://sea2.discourse-cdn.com/flex020/user_avatar/unity.neuraldsp.com/diffractioncircuit/32/3793_2.png) [@DiffractionCircuit](https://unity.neuraldsp.com/u/DiffractionCircuit)\ **Post date:** [May 14, 2024, 9:56pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/3 "2024-05-14T21:56:03Z")
Industry best practice: turn on the sound-producing device (QC in this case) before turning on any power to speakers. Do the reverse when powering off. Always always always. ---
**Author:** ![TieDyedDevil](https://sea2.discourse-cdn.com/flex020/user_avatar/unity.neuraldsp.com/tiedyeddevil/32/6455_2.png) [@TieDyedDevil](https://unity.neuraldsp.com/u/TieDyedDevil)\ **Post date:** [May 14, 2024, 11:20pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/4 "2024-05-14T23:20:52Z")
To clarify: The QC main and send outputs must go to the same mixer. That’s the only way this’ll work. Also, this trick depends on using XLR connectors, hence the mention of a stage box and the mixer to which it sends your signal. You might get lucky if you try this using 1/4” TS cables, but I wouldn’t bet on it working as described. I agree about best practices. Power your input devices first; power amps last. Always! However, for the case where the power glitches while you’re playing at volume, this trick _does eliminate_ the several seconds of hum until the QC re-establishes the XLR ground after the power glitch. Belt _and_ suspenders, eh? 😉 ---
**Author:** ![tomfs](https://sea2.discourse-cdn.com/flex020/user_avatar/unity.neuraldsp.com/tomfs/32/3645_2.png) [@tomfs](https://unity.neuraldsp.com/u/tomfs)\ **Post date:** [May 15, 2024, 1:25pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/5 "2024-05-15T13:25:57Z")
> [@DiffractionCircuit](#): > > Industry best practice: turn on the sound-producing device (QC in this case) before turning on any power to speakers. Do the reverse when powering off. Always always always. I feel this needs to be made into a plaque and given out when someone buys a QC (or any amp/mixer/speaker even). ---
**Author:** ![DiffractionCircuit](https://sea2.discourse-cdn.com/flex020/user_avatar/unity.neuraldsp.com/diffractioncircuit/32/3793_2.png) [@DiffractionCircuit](https://unity.neuraldsp.com/u/DiffractionCircuit)\ **Post date:** [May 15, 2024, 2:18pm UTC](https://unity.neuraldsp.com/t/qc-grounding-hint/14117/6 "2024-05-15T14:18:43Z")
> [@TieDyedDevil](#): > > I agree about best practices. Power your input devices first; power amps last. Always! However, for the case where the power glitches while you’re playing at volume, this trick _does eliminate_ the several seconds of hum until the QC re-establishes the XLR ground after the power glitch. Belt _and_ suspenders, eh? 😉 Fair. You understand why powering input devices first is important. Far too many others do not.