The new CAD USB II-R Cable

The CAD USB II-R Cable was awarded the USB Cable of 2023 by HiFi+ Magazine!  Read here:   

CAD has been designing USB cables for over 10 years and have just released what we feel is our finest USB cable. Reviewers, our customers and dealers all agree.

Read the first two reviews here:

“the USB II-R is now the cable that can preserve the most authentic account of the music so far, acting almost like an analogue conduit from PC to DAC. Against any known contender, this winner takes them all” 

HiFi+ Magazine – April 2023

“I made a number of comparisons with reference cables and came to the conclusion that CAD USB II-R is one of the most natural and effortless digital connections available to the streaming enthusiast”

Jason Kennedy – Editor, The Ear – June 2023

Digital audio source components – from servers to streamers, CD transports to laptops – are real noise polluters in an audio system. Their CPUs, chipsets, switch mode power supplies, regulators and the like produce considerably more high frequency ‘noise’ than any analogue component. To stop this unwanted noise from interfering with your system’s overall performance, you need to tackle it before it reaches the analogue stage.

CAD’s USB II-R cable is engineered to filter out this noise from digital music sources before that noise can reach the digital to analogue converter (DAC).

The new CAD USB II-R cable replaces CAD’s highly successful USB II cable. Designed for use with any server, computer, USB re-clocker or DAC/streamer, it builds upon the patented filter design used in its predecessor, which reduces high frequency noise on the USB differential signal, the Signal Ground and the +5V connections. However, the USB II-R cable itself is completely new, both in terms of the conductors and materials used, and also in the construction techniques employed. The combined result is extra clarity across all frequencies, a larger soundstage with greater speed, and improved timing and rhythm producing a more realistic natural sound quality.

The new USB II-R cable is 1.2m long and we just came out with a 2.2m version.

The USB interface inside your DAC has two high frequency oscillators running in the MHz range.  These are made from a crystal material that is tuned to vibrate at an extremely accurate frequency when a voltage is applied.  So, if you connect a USB cable that is vibrating (even very small amounts) this will have an effect on the oscillators on the USB interface inside your DAC.  One of the designs of the USB II-R cable is to minimize vibration from your server reaching your DAC.

Compared to purely analogue devices (e.g. turntables), digital audio source components produce more high frequency “noise” (EMI/RFI). This is generated within CPUs, chipsets, switch mode power supplies and regulators and so on. Also the basic USB carrier frequency can be in the 200 MHz to 400MHz frequency range. Digital audio interconnects have a range of issues that are significantly different from analogue audio interconnects. During listening tests we found that when we reduced the amount of this “noise” from reaching the Digital to Analogue Converter (DAC), sound quality dramatically improved in our opinion.

Secondly, it is now widely accepted that the materials and construction of analogue cables can influence the quality of sound that a system produces, and our thesis (which again, is now more widely accepted) is that digital cabling has at least the same impact.

Noise reduction

CAD USB II-R Cable features our patented USB filter, which filters noise from the music source (whether a computer or audio server or streamer).

The USB consists of 4 connections:

1) +5V : Only used for powering devices – many DACs use this power source, but not all.

2) DATA+ : Differential signal, very high speed

3) DATA- : Differential signal, very high speed

4) Ground : Reference

Unwanted noise is present on all 4 connections. Our patented filter reduces the noise on the differential signal. +5V and Ground without damaging the signal or power delivery itself.

The +5V line contains exceptionally large amounts of high frequency noise. To minimize the amount of this noise from entering the DATA and Ground connections, the CAD Cable uses a separate highly shielded cable for the +5V line.

Wire materials and construction

CAD sees “Digital Signals” as very high speed analogue square waves. Conductors used for high speed signals use different materials and construction techniques compared to conductors that only operate at lower frequencies. As explained above there are 4 conductors in a USB cable. The requirements for the DATA+ and DATA- conductors are completely different from those for the Ground and +5V conductors.

When we compared conductors made with different materials and/or construction techniques we also noted sound quality differences. We have meticulously researched the best materials and construction techniques for the conductors inside our CAD cable. Our main measurement tool is subjective listening tests, but over time we learned what parameters are technically important.