Signal Projects Cables
Signal Projects Cables
HOW IT ALL STARTED
It was several years ago that we began our journey into the amazing world of music and sound engineering. The conditions were far from ideal since we had to work inside a relatively small studio suite, with very old and low-quality recording devices that many times were blurring the outcome of our work. But our enthusiasm was such and we were so excited by this process because we felt we had the possibility to contribute a few more pages to the endless book of music history. However, apart from being excited, I distinctly remember being frustrated with the final copy’s sound quality. On some occasions, there were colorations in the mid-band, while on other occasions there was an irritating lack of detail and to make matters worse on many other instances there were annoying distortions that were produced by the old and limited-capabilities equipment.
THE MOTIVATION
After a few years had passed, our studio suites were modernized with some of the finest and most expensive equipment available at that time. However, the strangest thing was that some of these irritating distortions continued to make their presence felt. It was the fact that led us to conduct several audition tests with various combinations between the devices and the peripherals of our studio, aiming at an effective solution. Having done that, we saw a notable improvement in sound quality and an instant disappearance of all audible distortions after the use of high quality cables with the proper specifications. That is what motivated us in 2005 and led us to the formation of a company specializing in the manufacturing of high quality cables for the demanding sound engineers and producers. The results were satisfactory and the demand for these products exceeded our initial expectations.
THE CHALLENGE
The true challenge for us lay in the fact that we needed to gain the confidence of the demanding audiophile, even though we knew that we had to invest a lot for a market of a much smaller size. However, factors such as the ongoing pursuit of perfection, our love for music and our great passion for high end audio, led us in 2007 to establish Signal Projects.
OUR AIM
Signal Projects is a company whose only intention is to manufacture superior quality cables that will assist audio and video devices to simulate the original event with higher accuracy and bring the listener one step closer to that. Our cables, with their sophisticated design, the effective insulation, the efficient mixture of high purity metals, the implementation of advanced shielding techniques and their superior construction, will help signals to travel with the lowest possible interference and become ideal connections for any reproduction device within any price range.
OUR PHILOSOPHY
Many believe that the manufacturing of audio cable is not an intricate process, basing their opinion on the simplicity of the product itself. In addition to that, the reality where anyone can take a simple wire, a set of plugs and a solder to make any type of cable, is undoubtedly a fact that reinforces their opinion. But if we want to be honest with ourselves, we have to admit that such cable applications, will never be able to provide the qualitative specifications required by modern audio and video devices. And if we consider those cases where some serious amounts of money have been invested on reproduction equipment, by people who want to refine the performance of their systems, aiming to bring themselves closer to the original event, then it would be totally unwise to rely on simplistic cable applications.
For those cases, we believe that cable making becomes a lot more demanding as a process, due to the large number of parameters that have to be considered and controlled in order to maximize the performance of reproduction devices. Factors like resistance, capacitance, impedance, inductance, skin effect, power loss, proximity effect, propagation delay and many others, need to be always measured and controlled during the manufacturing of high end audio cables, and in Signal Projects… we leave nothing to chance.
By aiming at the most effective discharge of noise currents from the shields of our cables, we have designed specific grounding configurations according to the requirements of each cable type.
Shielding
Based on the combination of Foil/Braid shields and of Foil/French BraidTM shields, we have designed specific shielding configurations for each type of cable that we produce, achieving the maximum protection from all kinds of emitted interferences. Additional protection against magnetically coupled interferences is also provided by the twisted pair structure of our conductors.
The appropriate number of twists per unit length and the accurate uniform continuation is helping our cables to achieve a very effective noise rejection. The efficiency of our shielding configurations and of our twisted pair structures can be proved by the impressively low transferred impedance values of our cables and of course by the accurate response across the audible frequency range, which is absolutely free of hiss and hum noises.
Grounding
Unbalanced interconnections
The traditional unbalanced interconnects are structured with one conductor and shield. In this configuration, the conductor is the carrier of positive signals and the shield is acting both as the negative path and the grounding path between the source device and the receiver device. Due to this structural characteristic, all traditional unbalanced interconnects are more vulnerable to ground loops that can be created when there is an increased potential in one of the two connected chassis.
The most effective solution to this problem can be provided by the use of balanced cable designs that can even be applied to unbalanced type connections. In this case, one conductor is used for the positive voltage, the other conductor is used for the negative voltage and the shield is usually grounded either on the input termination, or the output termination. In Signal Projects, our unbalanced interconnect cables are based on exactly the same internal geometry and cable design with our balanced interconnect cables.
More specifically, for the construction of our unbalanced interconnects we use a truly balanced configuration with two conductors of the same cross sectional area, of the same type, of the same metal and of the same purity for both the positive and negative paths. These conductors are protected by exactly the same shielding materials that we use on our balanced cables, with the only difference being on the grounding, which in this case is connected on the “output unit” termination.
The reason why we follow this specific grounding configuration is because a) in most cases the noise currents will find better grounding circuits with lower impedances as they go downstream from the sources to pre-amplification units and from the pre-amplification units to power amplifiers, and b) we believe that it is more preferable to guide ground currents to the units with the lowest possible gain amplification.
Balanced interconnections
Theoretically, the use of balanced cables would offer the best interconnecting solution for any audio and video device. Practically, this assumption would only be stable if the connected devices were based on entirely differential balanced circuits with proper grounding configurations.
Unfortunately, there are many audio and video devices which, even though offer the option of balanced input and output connections, they are based on pseudo-balanced circuits, which means that the truly balanced signal “before entering into” and “before exiting from” the processing circuitry, passes through transformers or additional amplifier stages in order to be converted from balanced to single-ended and from single-ended to balanced respectively.
This additional conversion path usually brings negative results in the overall performance of a system, since it is practically “canceling” the main role and the advantages of balanced cables and thus the advantages of a truly balanced topology. In most of these cases, the performance of balanced connections does not provide the expected results and the worst thing is that cable manufacturers cannot magically change the conflicting situation created by pseudo-balanced devices. On the other hand, the existence of some pseudo-balanced devices should never deflect cable makers from the original design characteristics of balanced cables.
In Signal Projects we are well aware of that and this is the reason why we strictly adhere to the basic design principles of balanced cable designs.
After conducting many tests on conventional techniques and after a very careful evaluation of their positive and negative aspects, we decided to follow a simple but very effective method in order to create directional ground paths on the shields of balanced cables, without affecting the fundamental characteristics of a truly balanced structure.
This method is applied inside the termination modules of our cables and it is based on a specific configuration of conductive materials that are used primarily to connect the shield with Pin 1 of both plugs and secondly to maintain a relative difference in the resistance values of these two ground connections. Knowing that noise currents tend to follow directions that lead to connections of an even slightly lower resistance, in our balanced cables the ground connections of female plugs will always provide a higher resistance than those of male plugs, because – as we mentioned above in the section of Unbalanced Interconnections – we believe that it is preferable to guide ground currents to the units with the lowest possible gain amplification.
Digital Interconnections
In most system setups, the reactive current that floats across the shield of digital audio connections is not high enough to harm the digital signal. However, in cases where a ground loop circuit is created and noise currents are sufficient enough to corrupt digital data by affecting their flow (increase of jitter levels), we may experience negative symptoms like hum noises between 50Hz and 60Hz, digital whistles at higher frequency ranges and even some irritating colorations in the mid-band.
In order to achieve maximum performance and at the same time to provide maximum protection against ground loops and externally induced interferences, we have built our digital cables according to the geometry and the grounding configuration of our analog interconnects. More specifically, both our balanced and unbalanced digital cables are based on balanced cable structures with one conductor for the positive, one for the negative and one shield. With regard to the balanced digital interconnects, the shield is grounded on both ends of the cable according to the AES/EBU standards and in order to create a directional ground path on the shield of the cable, we apply exactly the same method that we described above in the section of “Balanced Interconnections”.
Concerning our unbalanced digital interconnects, we do not follow the common co-axial cable structure that uses one conductor for the positive signal and a shield for both negative signal and ground, since we gained much better results with the use of a balanced cable structure and by having the shield connected only on the output plug, creating a directional ground path that leads to the receiver unit. The reasons why we chose the specific cable geometry and grounding configuration are presented above in the section of “Unbalanced Interconnections”.
Power cables
We prefer to avoid the use of transformers and chokes in cables that will be used to connect high fidelity reproduction devices, due to a number of reasons which are mostly related to signal distortion. After many tests on various system setups and while at the same time being focused on the elimination of common and differential mode noises, as well as any kind of electromagnetic interference, we developed a sophisticated design for all our power cables which is based on the use of three completely isolated conductors with a completely independent shielding and grounding configuration for each one of them.
The shield of each conductor is grounded only on the male plug and not on the IEC plug due to three main reasons. Primarily, because we want to create directional ground paths towards the earth in order to safely and rapidly guide all noises that are blocked by the shield. Secondly, because we want to completely eliminate the possibility of a ground loop creation in the shields of the cable and thirdly, because we prefer to use only the ground conductor as the main connection between the earth and the unit’s ground, avoiding all these unwanted situations where ground currents of the circuit use the shield of Line and Neutral conductor to travel to earth.
Finally, in combination with this highly effective geometry, the use of proper ferrites will provide additional protection against all types of noises, making our power cables the optimum solutions for any system application.