The E-Frog expands the functions of the Palmer PGA-01
TRILINE and can only be used in conjunction with it. It can
be used to switch between two amps routed to the same speaker
cabinet. The E-Frog consists of 2 power relays and an 8 ohm
dummy load. The relay routes the inputs from amplifier A/B
either to the internal dummy load or to the speaker cabinet
output. Since the amp linked to the dummy load doesn't receive
input from the TRILINE, the E-Frog dummy load functions as
a guard against internal feedback - consequently the impedance
only plays a secondary role. Speaker cabinets with 4, 8,
or 16 ohms may be used.
The important thing is to match the amp output impedance
with the speaker cabinet.