GHIELMETTI DIGITAL/ANALOGUE PATCH PANELS
These are patching systems all suitable for AES/EBU digital audio, RS422 and other data applications, as well as analogue audio. The range of patch and matrix panels produced by Ghielmetti is extensive, but as the concept of their configuration is initially somewhat complex until you are really familiar with them, a very limited selection is detailed here to avoid causing too much confusion. Please contact Technical Support for further information on the digital signal performance, and advice on all other items in the extensive Ghielmetti range, including matrix panels.
The basis of the system is a series of pairs of gold plated contact wafers, which run vertically within each panel (three pairs of wafers per channel per layer - A, B and ground). There are two layers of contacts in each panel, without connection between the layers. Circuit routing is by pins which make connections between the layers. Pins are either factory fixed, for the rear hard-wired connection, or inserted by the user at the front to establish routings. In its basic form therefore, the patch panel has no “normalling”. By the design of the exact lengths of the contact wafers, the precise patching and normalling possibilities are achieved.
Routing is achieved by inserting a plug into the lower row (the connection is made by the long pins on this plug linking the front and rear contact wafers). Patching does not break any contacts, so a “source” on the top row is simply patched to the “destination” on the lower row, just like a conventional jackfield. Effectively, with a plug inserted, the panel acts like a “half-normalled” jackfield, which is the way virtually all jackfields are wired in use.
The major differences are that as there are no socket switch contacts, as in a normal jackfield, a possible source of noise is removed. Additionally, “sources” and “destinations” are in the no-load state until connected by a normalling plug or patchcord, unlike a jackfield where “normal” paths are chosen at system installation, which can result in unwanted normal paths at a later date.
All connections are 3-pole, fully isolated. The fourth pin on the patching connectors is a polarising pin to ensure phase integrity, and performs no electrical function.
Unlike conventional jackfields, Ghielmetti patch panels are suitable for use with both analogue and digital signals, even mixed within the same panel. Exceptional crosstalk performance of over 100dB between adjacent channels (except Economy series) ensures that even low level digital signals pass with a minimal error rate, even when adjacent to channels with high level signals. Both balanced AES/EBU 110 ohm and unbalanced SPDIF 75 ohm signals can be handled.
The Economy range of lower cost panels omit the screening wafers that are fitted between adjacent channels in all other types. This reduces the adjacent channel separation to 80dB. Otherwise, they are similar in construction to the standard design.
Panels are available with various terminations. On ASF, CSF and USF ranges these are modular units that plug onto the back of the panel (one module per 8 channels, except SAG type which is one connector per channel), thus enabling cable termination to take place without the patch panel itself being present. The suffix at the end of the part code indicate the options:
||Solder lug modules
||Solder lug modules, with jumper caps to allow various screen configurations
||3-pole connectors, specifically for pre-terminating screened pair cables prior to installation (solder), supplied complete with 96 (CSF SA G types) or 48 (ASF Economy SA G type) connectors
||25 pin D-sub modules
||Krone IDC modules
A special panel version is for RS422 connections: this uses adjacent pairs of sockets effectively as one socket to connect all functions of the RS422 protocol, including the Sony-specific priority signal on pin 5 of the D-sub 9-pin connector. The stereo patchcords (stock codes 45-960, 45-970) are used with this panel.
Panels are available as standard in an anthracite (RAL7024) finish, apart from Blueline, which is white with blue grid markings.
Certain models are available with electroluminescent strip front panel illumination. A special 230V AC power supply is included with each panel. These models are denoted by ‘Light’ in the part code.
3-pole normalling plugs are available in a variety of colours to assist identification. 2-pole normalling plus are also available for the purpose of normalling both signal legs but NOT the cable screen, e.g. for use in fault-finding. Locking normalling plugs are also available to deny access to the upper input connection for use where high signal integrity is necessary e.g. digital audio/data. Patchcords are available in mono (single channel) or stereo (paired channel) types. Patchcord plugs are also available (not compatible with CSF 48 way panels). Lacing bars and designation strips are fitted as standard on most series, but the Blueline series is available with or without designation strips and a 1U sized lacing bar (bar available separately).
To make it more approachable to those people only familiar with conventional jackfield terminology, the table below gives some guidance. Note that the term “1 row” has been used to indicate a panel with vertical pairs of sockets, which can be normalled by insertion of the normalling plug in the lower row.
In some cases, sockets are grouped horizontally in pairs, the term “stereo pair spaced” has been taken from conventional jackfield terminology to describe this. All patch panels have one designation strip per row of sockets.
Patch panels are supplied complete with a full set of 3-pole normalling plugs, to allow normalling on all channels.
Patchcord plugs (45-981 & 45-982) are not compatible with 48 way CSF panels due to their width. Standard patchcords are compatible and can be used.