High gain amps generate high levels of noise

Quad Cortex Bug Reports
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1

CorOS Version: 1.4.1

Describe your issue:
Hi,

I finally had the opportunity to get my hands on a Quad Cortex. I was super excited to set up my recording and band live presets but I’m experiencing a high amount of noise that I get from high-gain amps.

When using high gain amps the noise levels are quite high, including buzz, hums, harmonics, and fizz.
It is an unacceptable amount of noise for recording and live settings.

Adding a noise gate to the chain helps, but when I start playing you can hear the noise through the playing, and especially when performing palm muting notes you can hear the crackling and fizz.

Steps to reproduce your issue:

Setup the following signal path:

  1. Simple gate
    Threshold: -50dB
  2. Green 808
    Overdrive: 0
    Tone: 10
    Level: 10
    3.EV101IIIS Red EL34 100W
    Gain: 2.9
    Bass: 4.4
    Mid: 5.8
    Treble: 4.1
    Presence: 2.5
    Resonance: 2.5
    Master: 3.0
    Output: 0
  3. 412 Eng Pro V30 18
    Default settings

I expected this to happen:
When I set up a high gain preset I should have an acceptable amount of noise.

I have tried the following things:

  • Adjusting input level, it doesn’t clip
  • Checking output level, it doesn’t clip
  • Plugin it into the FX Loop of an amp
  • Listening through the headphones output
  • Using Quad Cortex’s power supply
  • Using CIOKS DC7 power supply
  • Using passive and active guitar pickups
  • Using the ground lift option in the input
  • Adjusting impedance levels in the input
2

Hi @sudo_aptGet and sorry to hear you are having issues with noise etc. Are you monitoring with just headphones or FRFR, PA system etc? Also, do you hear the noise 100% or only when using USB audio etc? Lastly, which PS are you using as your post states you are using the OEM and CIOKS DC7.

Some amps provide a lot of gain such as the EVH series, you may need to adjust your noise gate. I recommend to utilize the built in NG by long pressing the input on your signal grid. If all else fails, feel free to email support@neuraldsp.com and they will get your sorted quickly.

3

Try the adaptive gate. I usually put one first in my chain, and then a second one between my last dirt pedal and my amp.

4

Have you tried the real amp?

As you know, hi-gain amps are noisy. And it’s specially noticeable (=disturbing) at low levels and in quiet environments. At least, for me. You know, when the drummer comes in…

I also get noise using amp models (I use 2 FRFR Headrush 108) but until I try at stage levels and check it, I’ll consider it normal. Like I’ve always done with tube amps.

I still haven’t used my QC live. Before I do that I want to take it to the rehearshal room and play it louder than at home. It’s funny, but we have so many gigs these days that we are not going to the rehearshal room. I have to book a few hours soon.

5

Hi everyone,

Sorry for the late reply, I wanted to wait until I tested in a live scenario before communicating any tests that I did.

First of all, I want to make it clear that I’m absolutely happy with my Quad Cortex! :smiley:

Second, thank you for everyone’s support and replies! It is cool to see the community helping each other.

Third, I’m happy to say that I manage to mitigate the noise to normal levels by switching the Green 808 with any other overdrive. Switching to any other overdrive reduced the noises drastically!

As I said I had a chance to test in the studio with my 4x12 and worked great. Thanks for everyone’s help!

I want to emphasise that the noise that I was experiencing wasn’t a normal high gain amp noise, it was more than that but again, I managed to fix it by replacing the overdrive.

In conclusion, I think there is a issue with the Green 808 overdrive specially with the tone and volume at max. Reducing the volume didn’t quite work but dialling the tone knob helped with some cracking noise in the high frequencies but the overall noise , fizz and hum was still there.

I’ll answer all the questions from you in order to share information in case someone experience the same issue.

@MP_Mod

Are you monitoring with just headphones or FRFR, PA system etc?

When I wrote the post I was monitoring using my AKG Studio headphones and also tested in the FX Loop of a boss katana 100.

Also, do you hear the noise 100% or only when using USB audio etc?

I didn’t test through USB audio. But the noise was there on every combination of settings that I tried.

rckelly89

Try the adaptive gate. I usually put one first in my chain, and then a second one between my last dirt pedal and my amp.

I tried your suggestion but it didn’t fix the issue unfortunately

@Rayosytruenos

Have you tried the real amp?

Yes, I own an Peavey 5150II and at our studio we have a EVH 5150 III, Mesa Boogie Duo Rect and a Mesa Boogie Mark III available.

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