21
EURODESK MX3282A
9.3 Normalled
Fig. 9.3: Patchbay mode normalled
Here, and in contrast to the half-normalled setup, the signal route of the rear phone jacks is interrupted when
you insert a plug both into the upper and lower front jacks.
9.4 Open
Fig. 9.4: Patchbay mode open
This mode is used to connect devices such as sound modules or CD players having no inputs of their own. This
saves space, as you can route the left and right outputs to one module (left - top; right - bottom) or patch two
devices to one module (top and bottom). Effects devices and 2-tracks can be configured this way, so the inputs
and outputs are positioned on top of each other.
Basically, the inputs are routed to the bottom and the outputs to the top rear-wall connectors. Avoid routing
digital signals over a patchbay as the pulse signal used for the transmission of such signals causes heavy
interference in analog signals. Additionally, normal patchbays change the impedance of the digital cable route,
which causes interference in the digital path. Use the BEHRINGER ULTRAMATCH SRC2000 specifically
designed for this and other digital signal-related functions.
Microphone inputs operate at a level several orders of magnitude lower than line levels (+4 dBu or -10 dBV).
Therefore, they should never be routed via a patchbay. In any case, patching in a field with 48 V DC (phantom power)
flying about is to be avoided at all costs. It is best to plug mics directly into the mixing console or via special XLR-type
wall boxes connected to the mic inputs of the console by good-quality balanced multicore cables (2-cond. + shield).
9.5 Patchbay Organization
Let us give you an example configuration that shows how you can most effectively use your patchbays. We
assume you own a mixing console with 16 mic/line inputs plus inserts, 8 direct outputs, 8 subgroups with 4
inserts, 4 aux paths with 2 stereo returns and one stereo master output including insert jacks. Added to this we
have an 8-track recorder (digital or analog), a few pieces of outboard equipment (FX, dynamics & EQs), a
CDplayer, tape deck, HiFi system and a headphones amp:
9. PATCHBAY