Marshall Code 100 Combo Amp makes high pitched quiet hum. Is this normal?


My code 100 makes this high pitched quiet hum. It makes a kind of a low volume noise almost like it's not coming from the speakers. It's almost like a high pitched electric buzz. It doesn't seem to interfere with the function of it but I just wanted to know if this is normal. The noise dosen't sound like it's coming from the speakers, but it's hard to tell. It sounds like an electrical high pitch buzz. Nothing else is on in the room. The lights are not florescent either.  I just want to know if it's supposed to be that way. I also went back to the store to see if the other Code 100 they have does the same thing ...and sure enough it DOES the same thing as mine.   Wha't causing this hum?

asked 22 Oct 2017 at 10:39 PM

Joe Teresi (13)
Hi Joe,

Does this happen on all the presets, the nature of the amp is meant to have some background noise, maybe try using the noise gate setting and adjust to see if that helps.

Kind Regards

Team Marshall
- Lee Tomlin 24 Oct 2017 at 03:17 PM
Yes. It happens on all presets. The noise is still there even if the volume is off completely or if the amp is turned up all the way. I will create an audio file or video and I'll add the link here so you can here what I'm talking about... I will try to get it done by tomorrow... - Joe Teresi 24 Oct 2017 at 03:25 PM
Hi Joe,

Can you email it to , we will have a listen and get back to you.


Team Marshall
- Lee Tomlin 24 Oct 2017 at 03:28 PM
Hello, I sent the email a couple of days ago, I hope to hear from someone very soon :) - Joe Teresi 26 Oct 2017 at 01:01 PM
Hello Joe,
One of our team member is in direct contact with you.
- JOANNA GREEN 26 Oct 2017 at 02:41 PM
Mine does this too. Even when all the knobs are turned all the way down. Seems to go away if I max out the master for some reason. Also have the code 100 combo. Please let me know as well. - chad osman 23 Dec 2017 at 08:57 PM
Hello, Turns out it's the cheap transformer that they installed in this model amp. As I learned from a Marshall Sales Rep, Finding the right transformer for this amp was the cause of the delay of the release of this amp. That's why it took so long for Marshall to get this amp to the market. Seems that they wound up using inexpensive parts to keep their costs low in the production of this amp. I would have been happier paying a bit more for higher quality parts. It's the transformer that is causing this hum buzz. I hate the noise. It's annoying... - Joe Teresi 24 Dec 2017 at 01:23 AM
Great. I just got this thing .Thinking about taking it back the noise like you said is annoying. Thanks for answering back. I would have paid more too. I’m not sure how they can push this amp for anything more than home practice with the noise it definitely would end up in a mix when recording or micing out for a live show.
It’s a shame I’ve owned lots of Marshall’s from the jcm series to the valvestate to the mg line. This amp is pretty disappointing quality wise in comparison. Maybe I will go with the dsl but it’s made in Vietnam too so a little skeptical. Again thanks for taking the time to answer back happy holidays.
- chad osman 24 Dec 2017 at 04:57 AM
I have the same issue so this isnt a factory defect? And have to live with that noise? - Ricardo Rivera 17 Mar 2018 at 03:07 PM
no response yet. Marshall must be really busy for them to make us wait a month and a half so far! - Joe Teresi 26 Apr 2018 at 05:37 PM
Hi ,

As the code 100 is a switch mode power supply, it does not have mains transformer, in the sense of a valve/transistor amp. The noise you hear when the amp is on and not being played is the natural noise made by the 100 watt amplifier. As long as the noise is not heard when the amplifier is being played and shouldn`t be picked up when being recorded, the amplifier is working as it should.

Marshall Support
- Lee Tomlin 01 May 2018 at 10:20 AM
Answers: 5


I created a youtube video to share.  Please watch and listen with headphones to really hear and understand what I'm talking about here.  Lets all compare notes.  Comment here if you are experiencing the same high pitched noise/buzz issue...

Copy and paste this youtube video address into your browser.  If you still can't find it, do a search on youtube for...

Marshall Code 100 Combo Amp Hum Buzz


answered 27 Mar 2018 at 02:14 PM

Joe Teresi (13)
Exact same issue with my code 100 combo; waiting on marshall comments - Ricardo Rivera 27 Mar 2018 at 02:32 PM
Exact same issue with my code 100 combo - Adriano Figueira 23 Apr 2020 at 06:19 AM
by it new yesterday - Adriano Figueira 23 Apr 2020 at 06:20 AM
same issue as well - Aiden Fieweger 23 Jun 2020 at 11:58 PM


For what it is, it's still a great amp. The hum buzz doesn't get louder no matter what volume it's set to. If you are using this amp to play out with, I think it will be fine. A loud bar will cover the hum buzz. As far as practice it hone recording, it is what it is. I still love the sound of this thing. By the way, I also own a JCM 800 with a vintage 1960 cabinet. And I also just purchased a DSL 100H head and matching cabinet from  I LOVE IT!  My band just opened for Dokken last week and in my 36 years of playing, I received more compliments from my DSL100H rig than any other rig in my whole career of playing in my local bands. Not that expensive and sounds so good. Talk to Yuval from Sweetwater tell him Joe from Rochester sent you!  I promise you will not be disappointed in this amp and matching cabinet!

answered 24 Dec 2017 at 11:13 AM

Joe Teresi (13)
When your saying matching cab for the dsl I assume your talking about the MX412.
Have you ran your dsl through your 1960 cab? How do they compare? I’ve always like the 1960 cabs
- chad osman 24 Dec 2017 at 03:52 PM


Hi Joe,

Thank you for your Youtube clip, we will get one of our engineers to have a listen and we will get back to you soon.


Marshall Support

answered 27 Mar 2018 at 02:21 PM

Hi Marshall any update? - Ricardo Rivera 26 Apr 2018 at 04:53 PM


Here is another Youtube video I created.  Please listen with headphones to get the full effect...

Just copy the link and paste it into your browser.

PLease add your comments here if you are having the same issue with your Code 100 Amp.  We can compair notes...

edited 27 Mar 2018 at 06:43 PM

Joe Teresi (13)

answered 27 Mar 2018 at 06:42 PM

Joe Teresi (13)


I've bought my CODE 100 two weeks ago and it has the same problem. It's a shame because I verry much like all the possibilities of this amp. So the question is, should I return it while I can or should I wait for a silution by Marshall? It can't be that hard to privide a better trafo.

answered 30 Apr 2018 at 07:12 PM

Paul Pfann
That would be up to you. If it doesn't bother you, then keep it. If it bothers you like it does to me, then take it back or sell. I've already pre ordered one of the new Marshall MG102GFX 100-watt 2x12" Combo Amp w/ Effects. We will see how that one goes... - Joe Teresi 01 May 2018 at 02:25 PM
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