Welcome to my auctionsFeel free to ask any questionPlease read below This auction is set for Worldwide Shipping expenses. Worldwide shipping: $24.75 For sale: Linn Ittok tonearm cable with BNC plugs and earth lead, for use into Naim preamp phono BNC. A cable I used back then with my Linn Sondek LP12 with Linn Ittok tonearm into my Naim Nac 72 preamp/phono.Lenght 1.1 Mtr This cable will match any Linn tonearm. Lovely condition, stunning sound.Fully working orderActual pictures Please notice my other auctions, for example Naim na523 MC moving coil phono cards. Thanks for looking.

Welcome to my auctionsFeel free to ask any questionPlease read below This auction is set for Worldwide Shipping expenses. Worldwide shipping: $24.75 For sale: Linn Ittok tonearm cable with BNC plugs and earth lead, for use into Naim preamp phono BNC. A cable I used back then with my Linn Sondek LP12 with Linn Ittok tonearm into my Naim Nac 72 preamp/phono.Lenght 1.1 Mtr This cable will match any Linn tonearm. Lovely condition, stunning sound.Fully working orderActual pictures Please notice my other auctions, for example Naim na523 MC moving coil phono cards. Thanks for looking.

Naim DC1 BNC - BNC Digital Cable Bought brand new from UK dealer. Only used for testing. Shipping: Will be shipped by International FedEx Priority. Please contact me BEFORE paying , I can check a more accurate shipping rate for you. Shipping price/service shown in this listing is for reference only (as it force me to pick USPS for US post and can’t choose FedEx for international)

75 Ohm SPDIF cable - rare BNC-RCA ideal for CHORD, NAIM LINN DACs etc. as you can connect without using adaptors which compromise performance. This is a coaxial - 75 Ohm cable Length of cable – why 1.5m? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better. The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind. Why SPDIF cables should be 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

75 Ohm SPDIF cable - rare RCA - BNC ideal for CHORD, NAIM LINN DACs etc. as you can connect without using adaptors which compromise performance. This is a coaxial - 75 Ohm cable Length of cable – why 1.5m? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better. The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind. Why SPDIF cables should be 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

High Quality Audiophile Genuine LINN Tonearm Cable with BNC Connectors.I found this in a box of a Linn Ekos (Mk.1) tonearm. Its in excellent condition. Its listed as used but I believe this cable was never actually fitted and has just sat in the box from new. Although believed to fit the Ekos tonearm it may also be suitable for other Linn arms? Please study all photos and do your own research before bidding.The cable is suitable for connecting to older classic Naim NAC preamps with a BNC connections such as the NAC52, NAC72, NAC82.. and possibly other pre-amps. Again, please do your own research. The cable measures approx. 120cm long.Like with any second hand audio cables, I’d recommend testing the cable before plugging it in to anything valuable. I only mention this as it’s likely to be used with very expensive, high end audio equipment, so wanted to be clear that the buyer does this at their own risk. It will be very well packed and sent by Royal Mail Tracked delivery. For overseas bidders I use eBay Global Shipping Programme.

Please check out my other items.

Naim N-DAC Digital Analogue Converter, boxed plus usb/spdif convertor bnc cable. Includes box, packaging, instructions and original snaic (unused). All four optical blanking plugs are present. Owned from new. In excellent condition and works flawlessly. I am including an usb/spdif convertor and an atlas bnc cable. This combination allows you to plug a computer (Ive only tried it with a mac, which doesnt require any drivers) into it and get bit perfect HD audio. If you are looking at this dac you probably know the brand and the reviews it had. For example: https://www.whathifi.com/naim/dac/review Here is the web page from naim: https://www.naimaudio.com/product/dac The included spdif/usb convertor is this (also in fantastic condition): https://www.ebay.co.uk/itm/334931020693 Collection preferred. I am now enrolled in the eBay global delivery program. So delivery options are adjusted as above.

Naim DC1 BNC To RCA Digital Interconnect.

Please check out my other items.

Naim N-DAC Digital Analogue Converter, boxed plus usb/spdif convertor bnc cable. Includes box, packaging, instructions and original snaic (unused). All four optical blanking plugs are present. Owned from new. In excellent condition and works flawlessly. I am including an usb/spdif convertor and an atlas bnc cable. This combination allows you to plug a computer (Ive only tried it with a mac, which doesnt require any drivers) into it and get bit perfect HD audio. If you are looking at this dac you probably know the brand and the reviews it had. For example: https://www.whathifi.com/naim/dac/review Here is the web page from naim: https://www.naimaudio.com/product/dac The included spdif/usb convertor is this (also in fantastic condition): https://www.ebay.co.uk/itm/334931020693 Collection preferred. I am now enrolled in the eBay global delivery program. So delivery options are adjusted as above.

Naim N-DAC Digital Analogue Converter, boxed plus usb/spdif convertor bnc cable. Includes box, packaging, instructions and original snaic (unused). All four optical blanking plugs are present. Owned from new. In excellent condition and works flawlessly. I am including an usb/spdif convertor and an atlas bnc cable. This combination allows you to plug a computer (Ive only tried it with a mac, which doesnt require any drivers) into it and get bit perfect HD audio. If you are looking at this dac you probably know the brand and the reviews it had. For example: https://www.whathifi.com/naim/dac/review Here is the web page from naim: https://www.naimaudio.com/product/dac The included spdif/usb convertor is this (also in fantastic condition): https://www.ebay.co.uk/itm/334931020693 Collection preferred. I am now enrolled in the eBay global delivery program. So delivery options are adjusted as above.

75 Ohm SPDIF cable - rare BNC-RCA ideal for CHORD, NAIM LINN DACs etc. as you can connect without using adaptors which compromise performance. This is a coaxial - 75 Ohm cable Length of cable – why 1.5m? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better. The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind. Why SPDIF cables should be 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

Karousel Bearing & Matching Inner Platter.Bearing is in excellent condition.Includes Linn oil.No original packaging.RRP £916

Naim DC1 digital interconnect BNC to BNC 1.25m boxed. Thanks for looking. Been used with an external dac to great effect in my naim system. Fully working but condition is used. Comes with original box but that shows some wear. Will send via Royal Mail tracked. Offers will not be replied to sorry. International postage will not be replied to sorry. Any questions just let me know.

Excellent condition.RRP £329

75 Ohm SPDIF cable - rare RCA - BNC ideal for CHORD, NAIM LINN DACs etc. as you can connect without using adaptors which compromise performance. This is a coaxial - 75 Ohm cable Length of cable – why 1.5m? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better. The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind. Why SPDIF cables should be 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

Excellent condition.RRP £329

Optimum length 75 Ohm SPDIF cable with high quality gold plated RCA and BNC connectors and noise reducing ferrite bead which removes high frequency noise from the ground of the cable. QEDs award winning Performance digital SPDIF cable to connect CD / digital player or streamer to DAC. High quality BNC connector on a QED Performance cable, the BNC is by Hicon by Sommer, and designed for hi-fi SPDIF 75 Ohm use. (Hicon plugs are used by Nordost for their 75Ohm cables costing many £100s).It is the same dark nickel colour and gold plated like the QED RCA. (QED BNCs are no longer made).The Ferrite is a HF - High Frequency version from Wurth of the highest quality. 1.5m RCA to BNCTriple shielded and true 75 Ohm construction. Burned in using the Tara Labs Cascade file and DeoxIt treated for better conductivity. Please see the excellent 100% feedback I have received for hundreds of QED digital and analogue cables I have assembled and sold. Background Q: Why do digital cables make a difference – isnt digital perfect sound forever? A: Because years ago, the designers of the digital audio interfaces decided that the audio signals should be sent imperfectly in real-time, rather than perfectly but late! Our day-to-day experiences of sending digital signals are that they arrive perfectly, so what is different about audio? I dont get errors when I save my Word document to my hard drive or send an email to my cousin in the US; how is it so hard to send a signal 1m between two hi-fi components? The critical difference between Hi-Fi and digital documents being sent is that the audio signals are sent IN REAL TIME WITH NO BUFFERING OR ERROR CORRECTION In the case of a document sent across the word or to the printer, the data is transmitted in packets and assembled by the receiving machine; in the event of an error, there is time to ask for the signal to be re-sent it, is error corrected, so the result is 100% perfect. This all takes time. The audio signal has no time for any of this. It is sent as a continuous stream (Hence the phrase Streamer) in real-time, so there is no time to process it. If there are errors, then they affect the sound. Why In real-time? - this was decided years ago in the audio industry to allow video and sound to be synchronised - otherwise, lip-sync issues will be caused when playing a DVD or watching TV. The SPDIF interface is applied not only for CD players but also for DVD, Blu-Ray, Streamers etc., not just audio. How do better cables help? Jitter The phrase digital cables is a misnomer. All cables are lengths of wire or glass fibre, through which ANALOGUE voltages or pulses of light are sent. In the case of a wire, the analogue signal is a so-called square wave representing the 1s and 0s of the digital signal. In theory, this should be perfect; however, in practice, this square wave is rarely square - instead, it has rounded edges. The rounder they are, the more timing errors are introduced, called jitter. (How does the receiving machine know where the transition from 1 to 0 is if the edge of the wave is not a sharp vertical transition but a curve or angled line?) Reflections In addition, as the signal hits the end of the cable, it is partially reflected, overlaying an out-of-phase rounded square wave on top of the original signal. This again contributes to errors. Longer cables reduce this issue; short cables are not a good idea. Interference Finally, Radio Frequency interference and Electromagnetic Interference can also introduce errors in the signal and affect the receiving equipment. This emphasises the need for good shielding; in some cases, using Ferrite beads can help with some special equipment. (They can also hinder if incorrectly specified). The better the cable, the squarer the wave, the less reflection, and the less spurious signals from interference. Length of cable – why 1.5m? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. Digital cables have an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to the diagram in the photos. The signal travelling down a SPDIF (so-called digital cable) is actually a square wave ANALOGUE voltage signal; however, in reality, this square does not have instantaneous changes - the squares are sloped and somewhat rounded off, too, as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determines how accurately the source can interpret the signal in value 1 or 0 and also timing which is not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth). It produces ghost images of itself, which can fool the receiver into thinking that the ghost signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the transition time frame from 0 to 1 or 1 to 0 before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables, the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection; thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line is that a longer cable eliminates the false readings from the ghost images and thus reduces timing errors, called jitter, and therefore sounds better. Measurements and experimentation have determined the optimum size to be 1.5m or more. Very detailed explanation- for the curious, accompanies the diagram in the photos. Why SPDIF cables should be 1.5m long, detailed explanation. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square wave, consisting of rising and falling edges. These edges are no more than voltage transitions from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (Note that this DOES Not happen instantaneously). The rise-time is important because this is what causes reflections on the transmission line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission line unless it was extremely long. Alternately, if the rise-time were less than one nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector. Typical stock Transports have around 25 nanosecond rise times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference and make the interface reliable. When the regulatory testing is done, they attach inexpensive, inferior cables and measure the emissions. To ensure that the manufacturer passes these tests, they take several precautions. One is designing in the slower than necessary 25 nanosecond rise-time. Another is inserting various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable. It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around two nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well-matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, mainly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection returns to the DAC, if the transition already in process at the receiver has not been completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state, and there you have jitter. Lets look at a numerical example: If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds), and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now, if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time. Unfortunately, better (usually more expensive) cables produce better digital sound. Blame the people who decided on the digital interface decades ago for not separating audio-only from the need to send audio with moving pictures.

*** LAST ONE - no more stock available *** QEDs award winning Performance digital SPDIF cable to connect CD / digital player or streamer to DAC. High quality BNC connector on a QED Performance cable, the BNC is by Hicon by Sommer, and designed for hi-fi SPDIF 75 Ohm use. (Hicon are used by Nordost for example for their digital cables costing many £100s) It is the same dark nickel colour and gold plated like the QED RCA. (QED BNCs are no longer made). 3.0m RCA to BNC or BNC to RCA - cable is symmetrical and thus bidirectional. Triple shielded and true 75 Ohm construction. Burned in using the Tara Labs Cascade file and DeoxIt treated for better conductivity. Please see the excellent 100% feedback I have received for several QED digital and analogue cables, I have sold over 10 of these in the last 6 months. Length of cable – why 1.5m-5m is the optimum range of lengths? Summary There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance). The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy. The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better. The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind. Why SPDIF cables should be 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss. So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

QEDs award winning Qunex P75 digital SPDIF cable to connect CD / digital player or streamer to DAC. Extremely rare 1.5m RCA to BNC as QED dont make this combination! I have fitted a new Sommer Cable of Germany Hicon BNC to a New Old Stock QED 75 Ohm cable. These BNC cables are designed for Audiophile use and cost me over £9 to buy from Germany, making this cable a bargain at under £30 delivered.Triple shielded and true 75 Ohm construction for reduced jitter.Burned in using the Tara Labs Cascade file for 48 hours producing a much smoother sound as a result.This sounds excellent with Chord, NAIM, Linn etc DACS with BNC as no adaptor is required which compromises performance by generating reflections and spurious signals causing jitter.Please see the excellent 100% feedback I have received for hundreds of QED digital and analogue cables.Length of cable – why 1.5m? SummaryThere are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. With Digital cables there is an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance).The reason for this requires an explanation. Please refer to diagram in the photos. The signal travelling down a SPDIF (so called digital cable) is actually a square wave ANALOGUE voltage signal, however in reality this square does not have instantaneous changes - the squares are sloped and somewhat rounded off too as it takes some time to change state from 0 to 1 or 1 to 0. The accuracy of the pulses at the end of the cable determine how accurately the source can interpret the signal in value 1 or 0 and also timing which not so easy.The signal reflects back off the ends of the cable, the plugs and connected equipment (echoing back and forth) and produces ghost images of itself, which can fool the receiver into thinking that the “ghost” signals are the original signals. With short cables, under 1m, the ghost signals arrive close to the originals within the time frame of transition from 0 to 1 or 1 to 0, before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables the reflection arrives too late to influence the receiver (The transition has already been recorded). Longer cables also mean lower amplitude or signal reflection thus receiver can more easily determine between the correct signal and the spurious reflections. The bottom line as that a longer cable eliminates the false readings from the ghost images, and thus reduces timing errors, called jitter and thus sounds better.The optimum size has been determined by measurements and experimentation to be 1.5m or more. Detailed Technical Explanation for those with an enquiring mind.Why SPDIF cables should be at least 1.5m long. When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square-wave, consisting of rising edges and falling edges. These edges are no more than transitions of voltage from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall-time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously) The rise-time is important because this is what causes reflections on the transmission-line. If the rise-time were very, very slow, say 50 nanoseconds, then there would be no reflections on the transmission-line unless it was extremely long. Alternately, if the rise-time were less than 1 nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector.Typical stock Transports have around 25 nanosecond rise-times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference, as well as making the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To insure that the manufacturer passes these tests, they take a number of precautions. One is designing-in the slower than necessary 25 nanosecond rise-time. Another is the insertion of various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created in using too short a digital cable.It is a result of the slow rise-time. When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around 2 nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well matched systems. When the reflection reaches the driver, it can again be reflected back towards the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss.So, how does this affect the jitter? When the first reflection comes back to the DAC, if the transition already in process at the receiver has not completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state and there you have jitter. Let’s look at a numerical example:If the rise-time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds) and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25 nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.

75 Ohm SPDIF cable - rare RCA - BNC  ideal for CHORD, NAIM LINN DACs, etc., as you can connect without using adaptors which compromise performance.  New cable and plugs assembled by me. This is a coaxial -  75 Ohm cable High-quality silver-plated oxygen-free copper to improve signal flow, which is especially important at high frequencies (SPDIF signals operate at very much higher frequencies (1.5 MHz and 3 Mhz) than other audio signals).Nitrogen-injected PE insulation lowers the dielectric constant to reduce signal losses.   Length of cable – why 1.5m? Summary   There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. Digital cables have an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance).   The reason for this requires an explanation. Please refer to the diagram in the photos.   The signal traveling down a SPDIF (so-called digital cable) is a square wave ANALOGUE voltage signal, however in reality, this square does not have instantaneous changes - the squares are sloped and somewhat rounded off, too, as it takes some time to change state from 0 to 1 or 1 to 0.  The accuracy of the pulses at the end of the cable determines how accurately the source can interpret the signal in value  1 or 0 and also timing which is not so easy.   The signal reflects back off the ends of the cable, the plugs, and connected equipment (echoing back and forth). It produces ghost images of itself, which can fool the receiver into thinking that the ghost signals are the original signals. With short cables under 1m, the ghost signals arrive close to the originals within the transition time frame from 0 to 1 or 1 to 0 before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables, the reflection arrives too late to influence the receiver (The transition has already been registered). Longer cables also mean lower amplitude or signal reflection; thus receiver can more easily determine between the correct signal and the spurious reflections.   The bottom line is that a longer cable eliminates the false readings from the ghost images and thus reduces timing errors, called jitter, and therefore sounds better.   Measurements and experimentation have determined the optimum size to be 1.5m or more.       Detailed Technical Explanation for those with an enquiring mind.   Why SPDIF cables should be 1.5m long.   When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square wave consisting of rising and falling edges. These edges are no more than voltage transitions from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage, and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously)    The rise time is important because this is what causes reflections on the transmission line. If the rise time were very slow, say 50 nanoseconds, then there would be no reflections on the transmission line unless it was extremely long.  Alternately, if the rise-time were less than one nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector. Typical stock Transports have around 25 nanosecond rise times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference and make the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To ensure that the manufacturer passes these tests, they take several precautions. One is designing in the slower than necessary 25 nanosecond rise-time. Another is inserting various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created by using too short a digital cable. It is a result of the slow rise time.    When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around two nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well-matched systems. When the reflection reaches the driver, it can again be reflected back toward the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss.   So, how does this affect the jitter? When the first reflection returns to the DAC, if the transition already in process at the receiver has not been completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state, and there you have jitter.    Let's look at a numerical example: If the rise time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds), and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now, if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25-nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.        

75 Ohm SPDIF cable - rare RCA - BNC  ideal for CHORD, NAIM LINN DACs, etc., as you can connect without using adaptors which compromise performance.  New cable and plugs assembled by me. This is a coaxial -  75 Ohm cable High-quality silver-plated oxygen-free copper to improve signal flow, which is especially important at high frequencies (SPDIF signals operate at very much higher frequencies (1.5 MHz and 3 Mhz) than other audio signals).Nitrogen-injected PE insulation lowers the dielectric constant to reduce signal losses.High quality gold plated 75Ohm Hicon BNC plug and 75 Ohm gold plated RCA plug.   Length of cable – why 1.5m? Summary   There are only two occasions in audio where a longer cable – or an optimum length cable is better than a short one. Digital cables have an optimum length of 1.5m or more. (The other occasion is for MM phono cartridges, which need a specific capacitance).   The reason for this requires an explanation. Please refer to the diagram in the photos.   The signal traveling down a SPDIF (so-called digital cable) is a square wave ANALOGUE voltage signal, however in reality, this square does not have instantaneous changes - the squares are sloped and somewhat rounded off, too, as it takes some time to change state from 0 to 1 or 1 to 0.  The accuracy of the pulses at the end of the cable determines how accurately the source can interpret the signal in value  1 or 0 and also timing which is not so easy.   The signal reflects back off the ends of the cable, the plugs, and connected equipment (echoing back and forth). It produces ghost images of itself, which can fool the receiver into thinking that the ghost signals are the original signals. With short cables under 1m, the ghost signals arrive close to the originals within the transition time frame from 0 to 1 or 1 to 0 before the transition occurs. A 1m cable means the reflection arrives at about the same time as the transition is to be recorded. With longer cables, the reflection arrives too late to influence the receiver (The transition has already been registered). Longer cables also mean lower amplitude or signal reflection; thus receiver can more easily determine between the correct signal and the spurious reflections.   The bottom line is that a longer cable eliminates the false readings from the ghost images and thus reduces timing errors, called jitter, and therefore sounds better.   Measurements and experimentation have determined the optimum size to be 1.5m or more.       Detailed Technical Explanation for those with an enquiring mind.   Why SPDIF cables should be 1.5m long.   When the SPDIF signal is launched into the cable from the Transport, it is essentially a voltage square wave consisting of rising and falling edges. These edges are no more than voltage transitions from about –250mV to +250mV, the rising edge transitioning from minus voltage to plus voltage, and the falling edge transitioning from plus voltage to minus voltage. When an edge transitions, it can be described as having a rise-time or fall time. This is the time it takes for the signal to transition from 10% to 90% of the entire voltage swing. (note that this DOES Not happen instantaneously)    The rise time is important because this is what causes reflections on the transmission line. If the rise time were very slow, say 50 nanoseconds, then there would be no reflections on the transmission line unless it was extremely long.  Alternately, if the rise-time were less than one nanosecond, reflections would occur at every boundary, such as the connection from the circuit board to the wires that go to the connector. Typical stock Transports have around 25 nanosecond rise times. The primary concern for the manufacturer is to pass FCC regulations for emissions and electromagnetic interference and make the interface reliable. When the regulatory testing is done, they attach very inexpensive, inferior cables and measure the emissions. To ensure that the manufacturer passes these tests, they take several precautions. One is designing in the slower than necessary 25 nanosecond rise-time. Another is inserting various filters in the Transport to eliminate high frequencies from the signal. As a result of these choices, there is a hazard created by using too short a digital cable. It is a result of the slow rise time.    When a transition is launched into the cable, it takes a period of time to propagate or transit to the other end. This propagation time is somewhat slower than the speed of light, usually around two nanoseconds per foot, but can be longer depending on the dielectrics used in the digital cable. When the transition reaches the end of the transmission line (in the DAC), a reflection can occur that propagates back to the driver in the Transport. Small reflections can occur in even well-matched systems. When the reflection reaches the driver, it can again be reflected back toward the DAC. This ping-pong effect can sustain itself for several bounces depending on the losses in the cable. It is not unusual to see 3-5 of these reflections before they finally decay away, particularly when using the best digital cables, which are usually low-loss.   So, how does this affect the jitter? When the first reflection returns to the DAC, if the transition already in process at the receiver has not been completed, the reflection voltage will superimpose itself on the transition voltage, causing the transition to shift in time. The DAC will sample the transition in this time-shifted state, and there you have jitter.    Let's look at a numerical example: If the rise time is 25 nanoseconds and the cable length is 3 feet, then the propagation time is about 6 nanoseconds. Once the transition has arrived at the receiver, the reflection propagates back to the driver (6 nanoseconds), and then the driver reflects this back to the receiver (6 nanoseconds) = 12 nanoseconds. So, as seen at the receiver, 12 nanoseconds after the 25 nanosecond transition started, we have a reflection superimposing on the transition. This is right about the time that the receiver will try to sample the transition, right around 0 volts DC. Not good. Now, if the cable had been 1.5 meters, the reflection would have arrived 18 nanoseconds after the 25-nanosecond transition started at the receiver. This is much better because the receiver has likely already sampled the transition by this time.