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Two types of jacks are used in the construction of the audio jackfields supplied by Bryant Unlimited;
Jackfields may be constructed using a mixture of '3 point' and '5 point' jacks. Two row jackfields are frequently supplied with the top row using '3 point' jacks and the bottom row using '5 point' jacks. This enables them to be wired in 'Half Normal' configuration for use with analogue audio signals. This is the most common form of normalling used in recording studios, post production suites etc.
For digital audio applications, and other more esoteric forms of patching used for example in transmission lines, '5 point' jacks are required in both rows of the jackfield.
AES Digital Audio is an impedance matched system that does not allow one source to be patched into more than one destination, so jackfields for this application need to be wired in 'full normal' configuration.
In transmission lines, it is very important to avoid accidental breaks in signal continuity, so jackfields are commonly wired in 'Double Normal ' configuration. Perish the thought that the audio for East Enders could be interrupted without someone actually meaning to do it!
If you require '5 point' jacks on both rows, please discuss this with a member of our sales department.
Half normalling a jackfield allows the user to listen to the source signal without breaking the normal signal path. It also allows the user to cross patch the source to a 2nd destination by plugging a patchcord into a jack on the top row and the other end into a jack in a different column on the bottom row. The action of plugging a patchcord into the bottom jack breaks the normal signal path and injects the signal coming through the patchcord into the line to the destination input.
In half normal wiring, the normalling wires are connected to the main contacts of the top jack, together with the incoming signal wires, and the switch contacts of the bottom jack. The outgoing signal wires are then connected to the mains contacts of the bottom jack.
Full normalling a jackfield means that plugging a patchcord into either the top jack or bottom jack will break the normal signal path. This means that each source signal can only be connected to one destination input at a time.
In full normal wiring, the normalling wires are connected to the switch contacts of both top and bottom jacks. The incoming signal wires are connected to the main contacts of the top jack and the outgoing signal wires are connected to the mains contacts of the bottom jack.
Double normalling is rarely used, except in circumstances where it is essential that the normal signals cannot be interrupted unintentionally. In order to break the normal signal path from top jack to bottom jack, the user has to plug one end of one patchcord into the top jack and one end of a separate patchcord into the bottom jack.
In double normal wiring, two sets of normalling wires are required. On set is connected to the main contacts of the top jack, together with the incoming signal wires, and the switch contacts of the bottom jack. The other set is connected to the main contacts of the bottom jack, together with the outgoing signal wires, and the switch contacts of the top jack.
Other normalling techniques, such as 'cross normalling', parallels and phase reverse pairs are too complicated to go into here. If you require information about these, please contact our technical department.
If all of the above is too much to bear and you would like a quotation for one of our professional wiring staff to wire your jackfields for you, please contact our sales department.
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