Electrical connecting apparatus

Abstract

An apparatus for selectively passing stereo, balanced, or unbalanced audio. The apparatus comprises at least one first three terminal connector 10, at least two second three terminal connectors 20, 30 and a switch S mounted between the first connector 10 and second connectors 20, 30. The switch S comprises three switching positions to selectively provide signals from the at least one first connector 10 to the second connectors 20, 30, in such a way that allows a balanced signal to pass through the device unhindered when in a first position (figure 4), that shorts signals in a second position (figure 5), allowing an unbalanced signal to pass, and which enables a stereo signal to pass through when in a third position (figure 6).

Description

This arrangement relates to electrical connecting apparatus. In particular, but not exclusively, it relates to a cable apparatus for connecting equipment such as sound equipment. Sound Engineers generally have to connect many different types of equipment together in various environments, such as in a studio, rehearsal room and performance venues, for example. For this, they are required to use many different types of connecting cable for connecting different types of signals. Typically, in a sound environment, signals may be of various types, such as stereo signals, unbalanced audio or balanced audio. Stereo audio obviously sends different sounds to left and right speakers or speaker arrays. An unbalanced audio cable uses two wires to connect devices. Typically this may be of a source such as an electric guitar. An unbalanced signal generally requires two wires in its cable, a signal wire and a ground wire. Three wire cable could be used, in which the signal is sent simultaneously on both signal wires. The signal wire carries the audio signal and the ground wire acts a reference point for the signal. However, the wire in the cable can also act as an antenna and will pick up unwanted noise. Since unbalanced signals can pick up noise as a signal is sent along the cable, they are generally used for short distances, such as for connecting a digital device such as an iPod, phone or guitar to a nearby amplifier. Balanced audio cables, on the other hand, typically uses a cable which has three wires; a ground, as before, and two cables which carry audio signal, one in positive polarity the other in negative polarity (differential). These are sometimes referred to as a “hot” (positive) and “cold” (negative) signals. In the transmission of a differential balanced audio signal, if any noise were to be introduced into the wires as the signal passes down the cable, the noise would be introduced into both the positive and negative signals equally. Thus at the receiving end of the cable, as the equipment it’s connected to uses a differential input and only outputs the difference between the two signal inputs, any noise the cable picks up along the way will be cancelled out. In addition, balanced signals tend to be louder than unbalanced signals. Balanced signals tend to be sent over XLR cables. Accordingly, a Sound Engineer will generally be required to carry many different cable types, stereo, balanced, unbalanced etc and, particularly where they have to travel to a remote performance location, or to move between performance locations rapidly, this can be problematic. The present invention arose in attempt to provide a device or cable apparatus enabling the transmission of different types of signal, so that Sound Engineer or other user is required to carry around less cables and pieces of equipment than before. According to the present invention there is provided an apparatus for selectively passing stereo, balanced, or unbalanced audio, comprising at least one first three terminal connector, at least two second three terminal connectors and a switch mounted between the first connector and second connectors, the switch having three switching positions to selectively provide signals from the at least one first connector to the second connectors, in such a way that allows a balanced signal to pass through the device unhindered when in a first position, that shorts signals in a second position, allowing an unbalanced signal to pass, and which enables a Stereo signal to pass through when in a third position. The apparatus may comprise a plurality of first and second connectors. This enables the provision of a single device which can provide, to the sound engineer, a choice of input and output connectors of different types, to use as desired / required to pass a required stereo, balance or unbalanced signal. Therefore each first connector may be an input, and the second connectors outputs, but in embodiment signals may pass in either direction, so that any connection is usable as an input or output. Preferably, to pass stereo signals the switch is arranged that either the left or right stereo signal passes along a route bypassing the switch to a first, left, terminal of an output, and a second signal from a second terminal of the input, is switched to apply a signal to a second, right, terminal of the output, to transmit stereo signals. Note that ‘Left’ and ‘Right’ refer to the left and right stereo signals respectively, not to any physical disposition. Preferably, to pass balanced signals, the switch is arranged such that a ground signal does not pass through the switch between an input and an input, and hot and cold signals are passed to respective terminals, thereby transmitting a balanced signal comprising cold, hot and ground signals. Preferably, to pass unbalanced signals the switch is arranged to supply a ground signal from the input to two of the three terminals of one or more of the outputs and the unbalanced signal to the third terminal of said output or outputs. The terminals my be any combination of phono, jack, mini-jack, XLR or other connections. The apparatus may comprise a switch and a plurality of fixed terminals comprising sockets (eg phono, jack, minijack, XLR, etc) for connecting input and output cables to so that user can plug their own cables in to terminals provided at the switch or a housing containing the switch. The apparatus may comprise one or more fixed terminals comprising sockets of suitable type, and one or more flying leads, to provide flexibility for a user who may want to use flying leads which are ‘permanently’ connected but also plug in one or more of their own leads. It may alternatively comprise exclusively flying leads. The apparatus may comprise a switch and one or more connections / terminals, and a housing providing at least one socket for connecting at least one input and / or output, and at least one flying lead. Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which; Figure 1 shows a switching device switched to a first switch portion for passing stereo signals; Figure 2 shows the device switched to a second switch position for passing balanced signals; Figure 3 shows the device switched to a third switch position for passing unbalanced signals; Figure 4 shows the switch part of the device in balanced mode; Figure 5 shows the switch part of the device in unbalanced mode; Figure 6 shows the switch part of the device in stereo mode; and Figure 7 shows a device having multiple inputs and outputs. The device includes a switch S which is more preferably a 4 pole 3 throw (4P3T) switch. This may for example be a multicomp TM toggle switch and is preferably of the one 1M41 series which is a 4 pole 3 throw (on-on-on) toggle switch). In a preferred embodiment, the switch is part no.1M41T1B1M1QE. This has four ‘poles’ 2, 5, 8 and 11, and eight ‘contacts’ in pairs; 1 and 3, 4 and 6, 7 and 9, and 10 and 12. These will all be termed pins in this specification Switches S1, S2, S3, and S4 enable, respectively, pole 2 to be connected to either contact 1 or contact 3, pole 5 to be connected to either contact 4 or 6, pole 8 to be connected to either contact 7 or 9, and pole 11 to be connected to either contact 10 or 12. These are shown most clearly in Figures 4 to 6 and labelled in Figure 5. Three switching positions are possible in this design. In the first switching position, shown in Figure 4, pole 2 is connected to contact 1, pole 5 to contact 4, pole 8 to contact 7 and pole 11 to contact 10. In a second switching position, shown in Figure 5, the first switch S1 and second switch S3 are moved, so that the first switch S1 will now connect pins 2 and 3 and switch S3 connects pins 8 and 9. Switch S2 continues to connect pins 5 and 4 and switch S4 continues to connect pins 11 and 10. In the third switching position all the switches are moved to the position of Figure 4 such that pin 2 is mounted to pin 3, pin 5 to pin 6, pin 8 to pin 9 and pin 11 to pin 12. The toggle switch switches all four switches S1 to S4 together, to the positions shown in Figures 4 to 6 respectively. The switch S may be a mechanical or electronic switch. Reference will now be made to Figures 1 to 3. The device comprises an input connector comprising three input terminals, and two output connectors each comprising three outputs which are connected to the switching device S. The input connector 10 includes a first connector 12, second connector 12 and a third connector 16. This may be of any desired type and may for example be a 3.5mm or other type or size of jack, XLR connector, a phono lead or other type of connector as will be well known to those skilled in the arts. The precise nature of these will not be further described. The two outputs 20 and 30 also each comprise three connectors. The first output 20 comprises terminals 22, 24 and 26 and the second output connector 30 comprises terminals 32, 34 and 36. As is shown in Figures 1 to 3 terminal 10 is connected to pin 9, terminal 12 to pin 5 and terminal 3 to connected to pin 11. Terminal 22 is connected to pin 6, terminal 24 to pin 4 and terminal 26 to pin 9. Terminal 32 is connected to pin 16 as mentioned previously. Terminal 34 is connected to pin 2 and terminal 36 is connected to pin 9. In the figures, as is conventional, actual connections are shown by dots and where lines cross without a dot these are not connected. In a first position of the switch shown in Figure 1 the device is used to pass a stereo signal. The switches are moved to the position shown in this figure and Figure 4. The stereo signal, as is well known, comprises a left signal, a right and a ground signal. These are shown in the figures as differentiated by different line configurations. The left signal is shown as a dot-dash line L, the right signal as a dotted line R and the ground signal as a dashed line G. The Send and Return labelling is for a special case, where mixing desks use a similar 3 pole jack connection to ‘Insert’ an external effect processor into the signal path. One conductor of the connection is used to ‘send’ a channel signal out to an external effect processor, and another conductor to ‘return’ it’s signal back to the channel. In Figures 1-3 solid lines represent connections that have been broken (shorted), by the switch position shown in that Figure. It is also noted that neither pin 7 or 12 on the swich is connected to any input or output. In the stereo mode of Figure 1, pin 2 connects to pin 3, pin 5 to pin 6, pin 8 to pin 9 and pin 11 to pin 12, internally within the switch. Thus, the left signal L passes along route L1 bypassing the switch, since the connection 11 to the switch is connected to pin 12. This connects to pin 32 of the second output 30 which therefore carries the left signal. The right signal from 14 is applied to pin 5 which is switched to connect to pin 6 and therefore connects terminal 22 of the output 20 which therefore becomes the right output. The ground signal G is connected to output 36 and also, because the output of this is connected to output 26, it is also connected as a ground signal to the right connector 20. Thus, the left output 30 has the left signal and ground applied to it and becomes a Left stereo output. The right output has a right signal and ground also attached to it and becomes the Right output. A stereo signal can thereby be passed. The other parts of the respective output 20 and 30, shown by outputs 24 and 34, are in fact shorted as these are not connected to any input signal, as is shown by the dashed lines on the figure. Hence, a stereo signal applied to the stereo connector 10 will be passed as a stereo signal to the output 20, 30 providing the right signal on output 20 and the left signal on output 30. In a second switching position, shown in Figures 2 and 4, balanced signals can be passed. A balanced signal generally has three signals, a cold signal C, a hot signal H and ground G. These applied to pins 12, 14 and 16 of connector 10. In this case, the internal switches are switched such that pin 2 is now connected to pin 1, pin 5 to pin 4, pin 8 to pin 7 and pin 11 to pin 10. The result of this, as shown in Figure 2, is that the ground signal does not pass through the switch but is applied to terminals 36 and 26. The hot signal 8 is applied to terminal 32 and also, because it passes between pins 11 and 10 of the switch S, to terminal 22. The cold signal C is accordingly passed to terminals 24 and 34. Thus, each of the outputs 20 and 30 receive a full balanced signal of cold, hot and ground signals and balanced audio can be passed. Figures 3 and 5 show the third switch position of switch S for passing unbalanced signals. In this case, in the switch, pin 2 is connected to pin 3, 5 to 4, 8 to 9 and 11 to 10. In effect, half of the four internal switches are switched as in the stereo mode and the other half of the four are switched as in the balanced mode. In this configuration an unbalanced signal can be passed. An unbalanced signal generally comprises a single signal and ground. When a three pin connector is used then ground is typically applied to the two of the three connections and the unbalanced signal to the third. This is shown in Figure 3, where terminal 16 has the unbalanced signal and both of terminals 12 and 14 are grounded (receive the ground signal). In this case, by virtue of the switch positioning, the unbalanced signal is provided to terminal 32 and also, because it passes through the switch between pins 11 and 10, to terminal 22. The remaining two pins of each of the outputs are connected to the grounded connections 12 and 14. Although specific configurations have been shown above, it will be apparent to the skilled reader that other methods of connecting the inputs and outputs may be with a similar switching arrangement, to achieve the same effect and will be able, with selective switching, to selectively pass stereo, balanced and unbalanced signals. The above describes the basic principle. In embodiments, several connectors may be connected to a switch such that a signal cable or device able to pass any number of different signals may be used. This device may essentially comprise a switch S as described above, with reference to Figures 4 to 6 for example, and a number of different types of connector. These may be, for example, any combination of phone, jack, mini-jack, XLR and so on. The embodiments also allow for isolation such that a signal switch arrangement can be used to pass two signals independently. An embodiment is shown in Figure 7. Note that embodiments may comprise a ‘central’ switch and a number of leads dependent from the switch. The leads may be permanently connected to the switch or may have plugs which can plug into the switch. In some embodiments some of the devices may be permanently connected and others connected as desired. That is, the device may have one or more terminals in the form of sockets for a user to plug their own cable in, and one or more ‘permanently’ connected ‘flying leads’. These may be of any suitable type, such as phono, minijack, RCA, XLR, etc. Some or all of the connections may be internally of a device having a housing and internal components. The embodiment of Figure 7 will now be described. In this, and in other embodiments, inputs and outputs are arranged in groups G1, G2 and G3 A first group G1 comprises six connectors. The connectors comprise a first connector 100 which is a 3.5mm mini-jack plug and typically this is provided as a flying lead having three terminals. A second connector 200 is a % inch jack plug, again having three terminals. A further connector is an XLR convert con (M / F) flying lead 300. A further connector in this group is a phono / RCA plug 400 which is designated for an unbalanced left signal, and a further connector 500 is a phono / RCA plug designated for an unbalanced right signal. These are flying leads in a preferred embodiment. There is also a further connector 600 comprising a 3.5mm mini-jack socket. This may be panel mounted in some embodiments. As shown, the 3.5mm mini-jack plug 100 and the phono / RCA plugs are phantom power blocked by circuitry 90 from the other connectors. Phantom power is a plus 48 volt DC power signal that travels from a mixing desk to a connected condenser microphone. This is needed for a condenser microphone to work and the audio signalling comes from a microphone to a mixer (as an AC signal the opposite way). Capacitors only allow AC to flow through them, of course, and not DC so the phantom blocking circuitry 90 blocks the plus 48 DC power from reaching certain connectors. Phantom power blocking is well known and will not be further discussed. In this group, the 3.5mm and % inch jacks are wired together tip to tip, ring to ring, GND to GND via the power blocking capacitors. The left phono plug is connected to a tip / left pin of the jack socket 600 and the right phono group 500 is connected to the right / ring pin of the jack socket 600. This enables this group alone to be used as a jack to phono plug lead in stereo or balanced mode. The embodiment comprises two other groups, the connectors of which are connected together. These comprise a first group G2 comprising a % inch jack plug 600, an XLR Neutrik convertCON™ 700 (both of these being configured as flying leads in a typical embodiment), a female XLR combi (which in effect comprises two connectors 800 / 900) and a right RCA socket 1000. This group comprising connectors 600 to 1000 is for the right or return signal. The final group G3 comprises a group of connectors which form a left or send signal and these comprise a % inch jack plug 1100, an XLR Neutrik convertCON™ 1200, a female / % inch jack XLR combination 1300 / 1400 (which in effect is two connectors) and a left phono / RCA socket 1500. The RCA / phono plug sockets 1000, 1500 will typically be panel mounted, as will be the female to % inch jacks / XLR connectors 800 / 900 and 1300 / 1400, and the other cables in this group, and the group comprising connecters 600 to 1000 will generally be flying leads. By providing some of these as flying leads and others as fixed panel connections (sockets) then an engineer or other user can simply plug certain devices into a unit housing the device or take a flying lead and plug it into their own equipment as desired. Other combinations and alternative configurations of fixed panel connections and flying leads may of course be used. An earth lift 92 is included in the circuitry. Earth lifts are well known to those skilled in the art and their purpose is known. Earth lifts can reduce ground-related noise arising from group loops and is useful or indeed essential in some environments. A double pole isolation switch 94, is also provided which includes isolation switches 96, 98. These act to separate the signal paths such that two separate signals can be passed. A first signal might be passed between connectors 600, 700, 800, 900 and 1000. A second independent signal might be passed between connectors 1100, 1200, 1300, 1400 and 1500. Thus, an extremely useful feature of the present invention is that the device may be used to pass two separate signals independently. The isolation swich is connected to each of the input connectors 100 to 600 and isolates them from the output devices 600 to 1500. This can ONLY be used to separate the connections when switch S is in balanced mode. Thus, by using a multi-input / output device as shown in the embodiment of Figure 7, the user is able to choose the type of connectors they want and the type of signal to be passed and to easily switch (by manipulation of switch S as described previously) to enable the passing of the required type of signal. The functioning of this is described below. Balanced Mode With switch S switched into the “balanced” configuration of Figure 4 and Figure 7, the first, second and third group (ie G1, G2 and G3) are all connected together one to one. That is, terminal a to terminal a, terminal b to terminal b and terminal c to terminal c. That is, the signals pass through so that each terminal (pin) of each of the output is connected to a respective terminal (pin) of the inputs This means that a jack lead can be connected to a jack lead, a jack to a mini-jack, a jack to an XLR, an XLR to an XLR and so on, and balanced signals can be passed. Unbalanced Mode When the switch is in the unbalanced disposition of Figure 3 all three groups are still connected together, however the cold signal in all groups is now connected to ground. This means that the signal path through the switch is unbalanced. Thus, unbalanced signals can be passed. Stereo / lnsert Mode By moving the switch to the stereo mode of Figure 1 the device becomes a stereo split enabling stereo signals to be passed. The left and right connections of the connectors of group 1 (100 to 500) are split / separated from the right signals and that left and right signals can be passed to an output device enabling the passing of standard stereo signals. The above general analysis applies for any number of connectors provided 5 in embodiments of the invention. Note that in stereo mode the separation / isolation switch 94 has no effect. The isolation switch generally separates between the second group of io connectors G2 and the third group G3. This means that the connecters (jacks and XLRs) of the first group can be used separately from those of the second group, enabling the transmission of two different signals.

Claims

1. An apparatus for selectively passing stereo, balanced, or unbalanced audio, comprising at least one first three terminal connector, at least two second three terminal connectors and a switch mounted between the first connector and second connectors, the switch having three switching positions to selectively provide signals from the at least one first connector to the second connectors, in such a way that allows a balanced signal to pass through the device unhindered when in a first position, that shorts signals in a second position, allowing an unbalanced signal to pass, and which enables a Stereo signal to pass through when in a third position.

2. An apparatus as claimed in claim 1 comprising a plurality of first and second connectors.

3. An apparatus as claimed in claim 1 or 2 wherein the or each first connector is an input, and the second connectors are outputs.

4. An apparatus as claimed in any preceding claim wherein, in a first switch position, the terminals of at least one of the outputs are connected to respective terminals of at least each one input such that an unbalanced signal can be passed between the at least one input and the at least one output.

5. An apparatus as claimed in any preceding claim wherein, when the switch is in a second position a terminal intended to carry a cold signal is connected to ground, enabling unbalanced signals to be passed between the at least one input and the at least one output.

6. An apparatus as claimed in any preceding claim wherein, in a third position of the switch, signal pass from respective left and right terminals of the input aredirected to respective left and right terminals of the output, enabling stereo signals to be passed between the at least one input and the at least one output.

7. An apparatus as claimed in any preceding claim including a plurality of inputs and a plurality of outputs and an isolation switch, such that when the isolation switch is in one position the device is useable to carry two independent signals, one from one input to one output, and the other from a second input to a second output.

8. An apparatus as claimed in any preceding claim wherein to pass stereo signals the switch is arranged that either the left or right stereo signal passes along a route bypassing the switch to a first, left, terminal of an output, and a second signal from a second terminal of the input, is switched to apply a signal to a second, right, terminal of the output, to transmit stereo signals.

9. An apparatus as claimed in any preceding claim wherein, to pass balanced signals, the switch is arranged such that a ground signal does not pass through the switch between an input and an input, and hot and cold signals are passed to respective terminals, thereby transmitting a balanced signal comprising cold, hot and ground signals.

10. An apparatus as claimed in any preceding claim wherein to pass unbalanced signals the switch is arranged to supply a ground signal from the input to two of the three terminals of one or more of the outputs and the unbalanced signal to the third terminal of said output or outputs.

11. An apparatus as claimed in any preceding claim wherein, the inputs and outputs are any combination of phono, jack, mini-jack, XLR or other connections.

12. An apparatus as claimed in any preceding claim comprising a switch and a plurality of terminals for connecting input and output cables.

13. An apparatus as claimed in any preceding claim comprising a device housing the switch and a number of connections.

14. An apparatus as claimed in any preceding claim wherein at least one of the 5 connections is a fixed panel mounted connection and at least one of the connections is provided by a flying lead.

15. An apparatus as claimed in claim 14 wherein the apparatus comprises a switch and one or more connections and a housing providing at least one socket io for connecting at least one input and / or output, and at least one flying lead.

16. An apparatus as claimed in any preceding claim comprising a switch and a plurality of fixed terminals comprising sockets for connecting input and output cables to.1517. An apparatus as claimed in any preceding claim comprising one or more fixed terminals comprising sockets and one or more flying leads.18

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