Nope, not quite that easy...but almost.
I don't have a DSL, I have a TSL and on mine there is a three pin connector located just south of the power tubes. If the DSL has one you are in luck. You will need a digital multimeter and a very small screwdriver...like one you use to fix eye glasses or computers.
When you swap out power tubes, the bias must be adjusted to compensate for the new tubes. Bias is read from the three pin connector via the digital multimeter (set to read in millivolts). There are two sides to the power amp, with two tubes running each side and bias must be set for each side. The far right pin on the connector is for the right side tubes, the far left pin is for the left side tubes and the center pin is common. Simply connect the multimeter common (black) lead to the center pin and then the red lead to whatever side you are adjusting.
You will need to power the amp so it will need a load (connect to speaker cabinet). To read your bias settings, you need to turn it off standby like it is ready to be played through. While looking at your readings off the multimeter, adjust your bias by turning the white inset screw next to the right or left pins on the connector. Then do the same for the other side.
I have a sheet somewhere that lists the bias settings for JCM2000 amps. Let me know if you feel like tackling it and I'll send it to you. Otherwise you will have to go to a tech and pay large money for the simple procedure. It is very very simple to do and there is no danger of shocking yourself and you don't even have to pull the chassis out or anything.
Again, that only applies if the DSL series have the same pin access for bias adjustment as the TSL.