I want to record my amp without a mic and hear it at the same time.

I have a Yamaha THR10 and a Focusrite Scarlett Solo. When I plug in the headphone out of the amp into the line input of the audio interface and listen to it using the direct monitor option of the audio interface (and some headphones) there is an annoying high-medium pitched buzz.

Skipping, the audio interface and plugging my headphones directly into the amp causes no buzz. I tried different cables and changing the gain or volume on the interface was also not the problem.

So basically with buzz: Guitar -> (input) AMP (headphone out) -> (line in) interface (Direct monitor out) -> headphones

Without buzz (but no recording ability): Guitar -> (input) AMP (headphone out) -> headphones

What causes the buzz and how can I resolve this?

2 Answers 2


It’s hard to say exactly but some causes can be a grounding issue between the two, the mic/line switch might be in the wrong position and also the fact that you are running a stereo headphone out into a mono line in which is not ideal.

I looked online and it appears the Yamaha amp has a USB out so why don’t you plug the amp directly into the computer to record your guitar tracks? The amp doubles as an audio interface so it’s not necessary to go into the Scarlett to track your guitars. Once your guitars are tracked you can switch to the Scarlett for tracking vocals and other instruments.

Check out this video at around 9:35:

  • Oke, pretty cool! I didn't know this. Switching audio interfaces is not really nice especially for live looping. Would it sound oke, if I used a small mixer in front of the amp input to put both my microphone and my guitar into the amplifier input? So Mic -> mixer -> amp input. And then also Guitar -> mixer -> amp input
    – Tristan
    May 22, 2020 at 10:27
  • So you want to track both vocals and guitar at the same time? I think running everything through the amp is not a good idea, it would color the sound of the vocal too much, and you can’t adjust Individual levels after you record. First try and see if you can clean up the amp signal into the Scarlett. Flip the electrical plug on the amp if it’s not polarized (that used to work in the old days, lol) experiment with the output volume and line/mic switch. If you still have a buzz try the amp into the mixer and see if that’s clean. If it is then do mic>Scarlett, and Gtr>amp>mixer>Scarlett. May 22, 2020 at 16:16
  • Another option is a mic with a 1/4” plug (or XLR-1/4” adapter) on the amp going to input 2 of the Scarlett. May 22, 2020 at 16:24
  • Oke, I think adding a mixer between the amp and the Scarlett is a good idea. I'll try that!
    – Tristan
    May 24, 2020 at 9:32

A large percentage of hum and buzz problems can be eliminated by making sure all the components are grounded at the same point. This can be achieved by plugging a Waber Strip into a single wall outlet and plugging all the components into the Waber Strip. That's my technique and it has served me well.

  • The interface doesn't have a seperate power adapter. However, the laptop it is plugged into via usb is charging in the same strip and that does not seem to help.
    – Tristan
    May 24, 2020 at 9:30

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