Do you have the feeling that activating LOW GAIN MODE doesn't work on your AMP1 because the middle footswitch doesn't flash three times after activating LOW GAIN MODE and/or because you only notice a subtle difference to Full Gain Mode? Then there is good news for you, because it is unlikely that your AMP1 has an error.
The middle footswitch does not flash
The AMP1 Mercury Edition has several software versions that behave differently when it comes to LOW GAIN MODE activation. With the first production batch, you will not receive any visual confirmation when activating the LOW GAIN MODE. With the release of the AMP1 Iridium Edition, we changed the software to allow the middle footswitch to flash three times when entering LOW GAIN MODE.
This software is installed on all AMP1 Mercury Editions produced in 2019 or later. To find out when your AMP1 Mercury Edition was produced, read this article.
The AMP1 Silver Edition has no Expert Features and therefore no LOW GAIN MODE. It only has the PRESET MODE.
The AMP1 Iridium Edition, on the other hand, has even more Expert Features than the AMP1 Mercury Edition. When you activate the LOW GAIN MODE, you will always receive a visual confirmation here - the middle footswitch will flash three times.
Is the AMP1 in Direct Access Mode?
Please also make sure that your AMP1 is in Direct Access Mode. Activating LOW GAIN MODE does not work in Preset Mode.
LOW GAIN MODE only subtly noticeable
Depending on the position of the Gain pot on your AMP1, it is indeed the case that the LOW GAIN MODE has a relatively subtle effect. You can find out here why this is the case, and what the LOW GAIN MODE is used for: What is the LOW GAIN MODE and how does it work?
More AMP1 Expert Features
You can find an overview of the Expert Features and which AMP1 model has which features here: Which Expert Features does my AMP1 have?