Check out the thread on CD-4 on this website. It has a sub thread titled "CD-4 equipment that works well". You can get good performance from CD-4, but it takes a little work to get it right. There you will find listings of cartridges and turntables that work well. Note that many fine turntables were built during the quad era that are CD-4 compatible, and they aren't hard to find. Look for thick signal wires, almost as thick as video cables. Garage sales and flea markets are good places to look. Since it was easy to modify the design of a turntable to make it CD-4 compatible, these turntables often found their way into stereo systems as well. A high quality table of the era generally was compatible. For matrix quad, the requirements are no greater than stereo, but for CD-4, low capacitance cabling is required, including in the tonearm itself.
The Quadfather