Controls include a pickup selector, master volume, and tone control; it is strung through the body.

Controls include a pickup selector, master volume, and tone control.

A master volume was introduced to make the volume levels more manageable.

Left-click this to check the master volume and adjust accordingly.

These were the second series of Marshalls equipped with a master volume, which allowed for more distortion at lower volumes.

In addition there are the usual master volume and tone controls.

Setting the master volume to around half as a starting point, the channels can be quickly matched for clean, crunch and lead levels.

Last comes the master volume rotary, with the mains rocker switch located to the far right.

A "Boost" control and a master volume were added in 1975.

The master volume affects all of these settings.