with Earth Loops
The most common problem in any
studio set up is the earth loop. This tiny annoying problem causes that
humming drone to appear, either on power up, or during recording.
To be dealt with effectively, we have to start by removing each piece
of equipment, until we hopefully find the cause of the problem. If we
do, then we can simply remove the earth wire of the offending unit. This
should deal with the problem immediately.
If you cannot find the source this way, then the problem can lie with
your choice of cables. Very few home studio owners consider the
importance of not just high quality cabling, but also using balanced
Any external units, be they FX or rack synths, are generally
unbalanced outputs. If this is the case, then I strongly advise the use
of Direct Injection boxes (D.I.) for recording. This will ensure that
the signal reaching the 2480 is balanced, and free of any external
interference. If the outputs are balanced, then use standard TRS cables
for ensuring balanced line cabling to your 2480 inputs.
If the problem is still not resolved, then we need to take more
Any studio set up, home or commercial, should only share one earth
connection. In larger studios, the actual current draw (amps) is
normally shared over several independent power line servers, or courses.
Lights will normally have a 10 ampere line, FX, the mixer and recording
mediums will use a 16 ampere line. If more is needed, then an additional
line will be used of 16A or 20A, depending on the source (heavy power
amps for example, or, surprisingly enough, heaters).
Normally, all earth connections to the installed studio equipment
will be physically removed - all but one, and normally the Power Amp
driving the control monitors. In the home studio set up, I have removed
all my earth wires, except the 2480. All my power cables are connected
to a major power extention (plug board), which in turn is connected to a
genuine 16 Ampere EARTHED line.
So I have zero earth loops, and if anything serious should occur, the
worst that can happen is that my 2480 internal PSU fuse will blow, or
the house earth-trip switch will flip. Just remember when choosing your
main Earthed Power Source, that the fridge or freezer is not on the same