These types use our multi-section technology to make high performance transformers for driving electrostatic loudspeakers from a 4/8 ohm amplifier output. Bandwidth depends on the source and load impedances but a response to 40KHz or better is possible with our new mid/high range (size F) transformers. 20Hz to 20kHz or higher is typical for our 40Hz transformers. Two transformers with their primaries in parallel and secondaries in series may be used with the center point of the output grounded to give double the output voltage. All secondary windings on our ESL transformers are center tapped. Please note the primary impedance is shown below as a reference for the power rating. You can drive from any impedance (the lower the better). The primary winding is not tapped. For size information note the size code letter and see Power Packages.