ADC Super XLM Mk. II (1976–1978)
A rare 4-channel pickup from ADC, released just as the dream of surround vinyl was collapsing.
Overview
The ADC Super XLM Mk. II is obscure, and it comes from the tail end of a failed format. Between 1976 and 1978, ADC released this 4-channel pickup at the moment the industry was walking away from quadraphonic vinyl. It wasn't built to be flashy or affordable. It was built for a niche that barely existed. You don’t find these lying around. When you do, it’s usually someone cleaning out an attic full of unplayed records and gear that looked cool in a 1975 stereo catalog.
It’s not a stereo cartridge, and it doesn't pretend to be. The XLM Mk. II is a 4-channel pickup, designed to extract four discrete audio signals from a single groove. That means if you had a compatible decoder, a properly cut SQ or QS record, and a receiver with four amps, you could get something close to surround sound from a turntable spinning in 1977. The principle is Induced Magnet, which ADC implemented as a moving iron design but wired to connect like a standard MM (moving magnet) cartridge. That small detail meant you didn’t need a special preamp - just the right decoder and a lot of patience.
Patience was in short supply back then. By the time the XLM Mk. II hit the market, quadraphonic records were already retreating into cutout bins. The format war between SQ, QS, and discrete systems had confused consumers, and most dealers didn’t know how to set up four speakers, let alone sell them. So the cartridge didn’t fail so much as get orphaned. It arrived late to the party.
The frequency response is 15 to 50,000 Hz, which was a lot for the late '70s. Most high-end stereo cartridges of the era topped out around 20,000 Hz, if they were lucky. ADC claimed +2/-5dB across that entire range. Believe the numbers or not, it shows they weren’t playing it safe. This wasn’t about warmth or musicality in the usual audiophile sense. It was about bandwidth and extension, and the ability to track everything the groove could hold, even if almost no records used it.
The rest is a blank. No tracking force specs. No output voltage. No channel separation figures. No weight, no dimensions, no stylus shape. That suggests a specialist product, sold in low volume, with minimal documentation.
There’s no evidence of how many were made, whether they were reliable, or what typically went wrong. No anecdotes about the sound or the setup. No magazine reviews praising its imaging or condemning its price. It was made for two years, and then it was gone.
Specifications
| Type | 4-channel pickup |
| Principle | Induced Magnet (Moving Iron, connection as MM) |
| Frequency response | 15 - 50,000 Hz +2/-5dB |
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