Quad Cortex High-Gain Noise – Normal Behavior or Faulty Unit?

Quad Cortex
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1

Hi everyone,

I’m trying to figure out whether the noise levels I’m experiencing with my Quad Cortex are normal or if there might be an issue with my unit.

Here’s what I’m observing:

  • Clean amps: No problems, even with a slight boost.

  • Crunch amps: Noise is OK on their own with mild gain. When I add an overdrive, noise increases.

  • High gain amps: On their own are quite noisy but as soon as I introduce an overdrive even with mild gain the noise becomes very noticeable, and for my taste, quite loud. (high frequency hiss)

I’ve recorded sound demos for reference. (all with no noise gate)

Sound Demos Clean, Crunch, HiGain

My setup:

  • Guitar: Ibanez AT100SB with DiMarzio passive pickups

  • Input level: -5.4 dB

  • Signal peaks around: -14 dB

  • I also tried hitting the input harder, but the perceived noise level stays about the same

High gain test:

  • Amp: Gojira HOT (5150-style)

  • Gain: 6.4

  • Master: 5 (12 o’clock)

  • Output: 0 dB

  • Overdrive: Green 808

    • Drive: 1.7

    • Level: 7.6

Crunch test:

  • Amp: Freeman 100 Rhythm

  • Gain: 4.5

  • Master: 3.3

  • Output: 0 dB

  • Overdrive: Green 808

    • Drive: 1.6

    • Level: 10

Other notes:

  • Tested different power outlets

  • Connected directly to my Studio Monitors via XLR (since this is used for grounding)

  • Stock PSU

  • I used the QC as an interface and played through Archetype Rabe Plugin. Then I compared the noise floor to my Apollo twin going directly without the QC connected. The twin is definitely less noisy and is not emitting this higher frequency hiss I am hearing with the QC.

Is this level of noise typical for high gain + overdrive on the Quad Cortex, or does this sound like something I should contact support about?

I’d really appreciate if others especially those using similar high-gain setups could share their experience or even compare with their own units. I currently use a noise gate on Input 1 and then a crossover noise gate at around 1,6k to deal with the noise I am experiencing.

Thanks a lot!

2

The noise seems very normal. Especially with Gojira at 6.4 with a boost at the settings mentioned.

A gate at the input will mainly help with any noise from your playing. I would highly suggest a gate with sidechain block that’s triggered from input 1. But place that immediately after the amp block. Adjust the controls as needed, but it will clear up this hiss.

Also the noise could possibly be less with your interface because of the gain of the input on that. being different than the QC. Also assuming you adjusted the noise gate in the plugin, which automatically is on when the plugin loads at the default setting

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The amount of noise sounds normal for this style of high gain (5150) amp block in the QC. A real 5150 powering a speaker cabinet would have this level of noise too. Nothing to worry about there.

Echoing what @SelfTitledLP said, place a sidechaining gate after the amp block and set the sidechain to Input 1.

4 Likes
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Thank you both for taking the time and responding! Glad to hear it is a normal amount of noise. I will try the sidechained gate after the amp.