SPDIF and RCA cables are used to transmit audio signals. RCA transmits analogue audio signals while S/PDIF transmits digital signals.
When it comes to comparing these two, the SPDIF is better than RCA, because SPDIF offers a connection that is very reliable, it will also give you a sound experience that is better and the audio quality of SPDIF is also higher than that of the RCA.
What is an RCA cable, do you really need it?
RCA cables are similar to coaxial SPDIF, the cables come at a cheaper price point and are used to transmit analogue signals between devices. With these cables, you cannot connect them to digital devices since they are used for analogue signals. With RCA cables, you can use them for video and audio signals. They are also used in a wide range of devices such as stereo, TVs, and speakers.
They are available in two main types, composite video RCA cable and component RCA cable. The signal quality that each of these cables transmits are different, component RCA transfers higher quality signals as compared to the composite video RCA.
These cables cannot support high-resolution formats because they do not have a high bandwidth. However, they are able to support 5.1 Dolby digital.
SPDIF
This abbreviation stands for Sony/Philips digital interconnect format. This kind of format is used for connecting a lot of components like DVD players, Blu-ray players, receivers, HDTVs and more to audio systems like surround sound receivers. SPDIF supports Dolby digital as well as DTS multichannel sound.
SPDIF will transit signals without changing them into an analogue signal, these signals are high quality. SPDIF can be used for a lot of connections including DVD players, CD players, sound cards and mink disc players. SPDIF can support a lot of formats, the most common format that it supports is the 48 kHz sample rate format. It can also transmit the 44 kHz format that is used in CD audio.
SPDIF is also used to transmit 20-bit audio data. It is also capable of transmitting 24-bit audio samples. The signals that are relayed on the optical connecting are the same as those that are related to the coaxial connection. SPDIF is also capable of carrying two channels of 5.1 or 7.1 surround sound or two channels of uncompressed PCM stereo. It does not support lossless sound formats because the bandwidth is not that wide. Lossless formats require higher bandwidth.
There are two ways in which the SPDIF interface is implemented: using coaxial and using optical.
Using coaxial SPDIF
The coaxial cable has an impedance of 75 ohms. It makes use of an RCA phono connector. Coaxial cable is a very good way to send audio signals from digital devices, since they are a standard if SPDIF, they can send signals without having to convert them into analogue signals.
The coaxial SPDIF cables cannot support lossless audio formats, this is because the bandwidth is not enough for the lossless audio formats.
Using optical SPDIF
Here, you will use a fibre optic cable in order to transmit the signals. Two types of connectors can be used, the Toslink connector and the mini optical connector. A mini optical connector is also known as the mini optical jack, mini Toslink or mini-plug. This kind of connector is prevalent in small CD players and can also be found in most audio devices. You will find the Toslink connector on many devices including CD players, DVD players, surround sound receivers and even DAT recorders.
Optical SPDIF cables come in different ranges. Some are suitable for home installations whereas others can be used for professional installations. All these are available in the market. Toslink connector has immunity to Radiofrequency interference and ground loops whereas coaxial cables are not. The Toslink are fragile and can easily be damaged.
Differences between SPDIF and RCA
Appearance
SPDIF Toslink uses fibre optic material it also uses fibre optic to transmit signals. This means the materials it uses include glass or plastic, the material ensures that data transfers are done fast and in a reliable manner. It does not use electricity for that. Instead, it makes use of light pulses to transfer the data. The Toslink uses standard SPDIF connectors. They are also capable of supporting many audio formats. The Coaxial SPDIF uses RCA connectors, the cable has conductive shielding, inside it, and it has an insulating layer with a rugged look.
RCA are usually made from copper, the connectors can be plated in gold, silver or copper. This is very good as it helps in reducing oxidation and are more affected by signal loss than optical or coaxial.
Application
Both SPDIF cables and RCA cables are used to carry signals from one device to another device. They are widely used in most sound systems and the difference is that SPDIF carries digital signals whereas the RCA carries analogue signals. With SPDIF, the signals do not need to be converted into analogue before they are transferred.
Signal Quality
In terms of the audio quality, the SPDIF excels. It offers signals that are clear, consistent as well as reliable, the quality it offers is good for both videos and audios.
Length
SPDIF and RCA cables offer almost the same capacity, the Toslink SPDIF cables are up to 16 feet. If you need to use these for long-distance communication, you need to have repeaters as well as other cables because this cable is very fragile, that is why the length capacity is not that good.
SPDIF coaxial cables have a thick and strong construction, that is why it has a distance of up to 16 feet. However, these are not very good for long-distance communication because they easily suffer from the signal loss.
Bandwidth
The SPDIF has a higher bandwidth than the RCA. The bandwidth of SPDIF can reach you to 750 MHz while that of the RCA is only about 6 MHZ.
Signal transmission
This is the main difference between SPDIF and RCA. Whereas the SPDIF deals with digital signals, the RCA transmits analogue signals. Another difference is that SPDIF does not need to convert the digital signal into an analogue signal for transmission.
SPDIF Limitations
Both standards of SPDIF have some limitations, the optical SPDIF cables are capable of handling data effectively when it comes to connecting them at long distances, but they become very fragile. This could lead to these cables being damaged especially when they are bent. When extending these cables, make sure to use repeaters and boosters so that they are well-protected.
SPDIF coaxial cables have good construction and durability. You will barely experience any problems in terms of durability. They are very strong and can last a very long time.
However, these cables experience a lot of RF and EM interference. When these cables have not been properly installed, they produce noise.
Why SPDIF is better than RCA
- There are so many reasons why SPDIF connections are better than RCA. RCA is on the decline while SPDIF connections are still being widely used in most devices nowadays.
- SPDIF provides good value for the money. Coaxial SPDIF is very cheap, Toslink SPDIF connections are also very cheap, and the performance is good.
- Using these cables is very easy, although they can be affected by interference and signal loss when connected at longer distances, you can use repeaters to give the signal a boost.
- SPDIF connections have a good capacity, they are capable of transferring very large amounts of data because of their capacity.
They also have a good design that ensures that they are very durable. Although, the Toslink SPDIF should be handled with care since they are fragile.
SPDIF coaxial vs RCA cables
Coaxial cables look a lot more like RCA cables especially in terms of their shape as well as sizes. Both of these makes have an impedance of 75 ohms, and the bandwidths are not very different.
However, coaxial cables are thick, they also have a good shielding that helps in reducing radio frequency interference and electromagnetic interference.
The main difference is that coaxial cables are able to transmit digital signals in a single cable, while RCA cables are not able to do this.
SPDIF vs RCA, which one to choose?
We have outlined the differences as well as the similarities between SPDIF and RCA. However, making a choice between the two can still be difficult for some
SPDIF offers a better experience than the RCA, this is because it gives you an experience that is very reliable, they are also easy to use, and the audio quality is higher than that provided by RCA. RCA also perform well, but, it will not give you the same experience as SPDIF. However, with RCA you will not be able to connect your digital devices directly.
