Magnetic transformers are inductive loads and are sensitive to DC voltages. A
magnetic transformer subjected to DC voltage can overheat. Do not use regular
incandescent dimmers for magnetic low-voltage lighting. Regular
incandescent dimmers often contain a small amount of DC voltage, which is
harmless to a regular incandescent load but may damage magnetic transformers.
Magnetic Low Voltage dimmers are specifically designed to prevent DC voltage
from being applied to the transformer.
Click on the picture below to see all available dimmers