4 ADC XLM Phono Cartridge Models 

1972 - 1980. A comparison of the 4 ADC XLM models, spanning 8 years. Upgrades to the XLM were mainly in the compliance, recommended VTF, coil inductance/resistance, and stylus mass. The first XLM was the only one designed by Peter Pritchard, the original owner of ADC. He was known for building cartridges with ultra-high compliance and ultra-low tracking forces; a combination that only the lowest mass tonearms could handle. When BSR took over ownership, compliance was lowered and VTF was raised making the cartridge compatible with the majority of tonearms/turntables. The last upgrade to the XLM resulted in a stylus mass that was 50% lower than the previous XLM models resulting in the highest tracking ability, flattest frequency response and lowest distortion of the series. A side note, the XLM MK II Improved uses the same body/coils as the XLM MK III with a lower quality stylus; it appears to be a re-branding of the VLM MK III.