The DSL40 has both gain and volume controls for the classic gain channel and for the additional ultra-gain channel. Both of those channels have two modes, for example, on the classic gain channel you can select either the clean or crunch and between two stages of overdrive on the ultra gain channel
On the DSL panel as well as a three-band EQ control, there is also a tone shift button, using this will help you scoop out some of the mids giving you a less mid-tone-based sound.
The DSL also has presence and resonance controls. Adjusting the presence will affect the upper frequencies of the amp, impacting how bright the treble response will be, helping you cut through a mix. Turning the resonance up will bring in more low to mid frequencies, thickening and defining overall tone.
The DSL40 also has two reverb controls, one for each of the two channels. There are also two master volumes, something that is especially useful if you are playing live and you need to be able to give yourself that extra volume boost when playing lead parts. Having two volume controls means that the amp will have a master control, where you have a general area of volume but if you have a solo coming up, you can use the foot switch to engage the second master volume to boost yourself to make sure you are heard.
Unlike an ordinary on-off switch, the Pento Triode standby switch gives the DSL three positions, high, low, and standby. When switched onto high it gives the amp its full 40 watts of power. On low, it will only go to half power, so roughly 20 watts. In the standby position, the amp can still be used and emulated out for either headphones or home recording.