Radial Engineering JDI Mk3 User Manual page 11

The Radial JDI features an isolation transformer that will generally eliminate most of this type of noise. But in severe cases,
lifting the ground on pin-1 at the XLR by depressing the GROUND switch can help. When lifted, this assumes the ground
will be derived by connection of the THRU, through the cable shield, to grounded equipment such as an amp.
Note that when you are 'going direct' by connecting a bass or acoustic guitar to the Radial JDI without using the thru-put,
the ground switch should be set in the out position so that the JDI is grounded at the mixing console. If you are using the
thru-put to your personal amp, then your amp and the mixer will have ground paths and lifting the ground would then be
considered.
Parallel speaker connection and the SPEAKER switch
IMPORTANT: THE JDI IS NOT A LOAD BOX! You must ensure that the amplifier is connected to it's speaker
load first as the JDI is not designed to handle the load on its own.
There are occasions when you may wish to 'tap' the 'wet' signal off the output side of an amplifier as opposed to taking
the 'dry' signal directly from the instrument. Examples would be capturing the EQ and compression settings from a bass
amplifier, recording the distorted sound of a guitar amplifier, or maybe combining the sound of a mic'd amplifier with a direct
feed off the speaker.
Radial Engineering
9
True to the Music
JDI User Guide