After a minute or two when first switched on the amp makes a loud scratchy/radio interference/cracking noise for a few seconds and then settles down. What is causing this please?
Hello Malcolm,
The noise could be caused by a faulty valve or a component in the power supply, we would recommend that you have the amplifier looked at by a qualified engineer. If you would like us to look at it for you then please contact jgreen@marshallamps.com.