I noticed my Marshall Code  25 makes a hissing noise when I play through any of the clean amp models. This hissing noise is clearly audible when I play a note on the low E string. It reminds me of an old cassette tape. This is especially apparent with the cab emulation switched off. On the higher strings there is no problem. Is this normal? The hiss doesn't go away with the noise gate turned on.  I have this problem with both firmware versions 1.44 and 1.45. 

EDIT: found out that when I put my amp in bluetooth pairing mode it stops. Sound also comes out the speaker itself. So it's something internal for sure

----------

I have a CODE 100C and when I connect it to my interface with the HP out (or even the fx send -- or even when using the HP out as a HP out) I have this high end hiss/artifact.

Here is a recording of the sound: https://youtu.be/a9mjRFiqVX0
obviously it's not as loud as in the video.. but it's still there

Recording with the HP out is the best way for me to elimante latency, but the sound quality is just bad. Also with USB I can't get acceptable latency..

Hi Marshall, I have just purchased a Code 100h and 412 that sounds great, however, I notice that when I play a chord there is a sound coming from the amp after the chord dies down that sounds like a cyclicle click and hissing. I have tried different leads and plugged it in a different socket but still get this consistantly after holding a chord down?

Bought a CODE 50 two weeks ago and LOVE the tones - great reproductions! But I have the hissing problem as well. Quite noticeable as a chord or note decays. At first, thought it was normal 60-cycle single coil pickup hum, but it is not.

Read similar Posts on the Forum, so tried the firmware update and it did not help. Noise gate not really an effective alternative, either.

Team Marshall, any other solutions in the work Again, otherwise I love the amp and want to keep it.

Thanks.