A major benefit of using transformers is the elimination of noise caused by ground
loops. The transformer isolates the devices connected to it by decoupling the
signal ground between the input and output. This isolation effectively breaks
ground loops between devices and blocks hum and buzz.
GROUND LIFT
To make grounding as flexible as possible, both units feature a ground LIFT
switch. When in the lifted position, the input signal ground is decoupled through
the audio transformer and isolated from the output signal ground. If you hear
hum or buzz, try depressing the LIFT switch and use the position that produces
the least noise.
LEVEL CONTROL
The J•ISO and Pro-ISO feature a variable audio level control that can be called
upon to attenuate hot signals and prevent the inputs of the destination audio
device from clipping.
RCA & 3.5mm JACKS
Consumer audio electronics such as mobile recorders connect directly using the
3.5mm and RCA inputs, thus eliminating the need for cumbersome adapters.
Two ¼" phone jacks are also provided. All output jacks are wired in parallel and
can be used to split the stereo signal and send it to a second audio device. You
can connect a mixer to the RCA outputs and a mobile recording device to the
3.5mm phone jack and record the signal on both. Keep in mind that the source
audio level may need to be increased to drive the additional load that a second
device presents.
SECONDARY GROUND LIFT
A secondary recessed ground lift switch is accessed through a small hole in the
side of the enclosure. This switch disconnects the common ground connection
between the left and right output jacks. For normal stereo operation with one
audio device connected to the outputs, this switch can be set either open (pushed
“out”) or closed (pushed “in”).
However, if you intend to connect a second device or use the J•ISO in dual
mono mode (where the left and right output channels drive two separate audio
devices) there may be a gain in noise performance by depressing this switch. If
you hear hum or buzz while operating with two devices connected, try toggling
the recessed switch and use the setting that produces the least noise.
J•ISO / Pro-ISO User Guide
Radial Engineering Ltd.
