ADC RQ-4 (–)

A tiny diamond tip that kept the music spinning - simple, durable, and built to trace grooves without fuss

Overview

The ADC RQ-4 is a replacement stylus. It's not a flagship. It's the part you ordered when the old one finally gave up after years of service. It was designed specifically for the ADC Q-4 (or Q4) phono cartridge. Owners report good rendition of voice and music, which is solid praise for a conical diamond tip in its class. This wasn't a hyper-precise elliptical stylus chasing audiophile approval. It was a workhorse, built for reliability and longevity.

The RQ-4 is described as having a long playing life. That mattered when replacing a stylus meant recalibrating tracking force and alignment, not just snapping in a new one. Many entry-level cartridges of the day came with steel or sapphire tips that wore down records (and themselves) quickly, so a diamond stylus, even a conical one, was a meaningful upgrade. The tip is highly polished, which likely helped reduce groove wear and keep contact consistent. There are no original specs on tracking force or compliance on the page, but replacements are still available today.

Specifications

Manufacturer	ADC
Product type	Replacement needle/stylus for phono cartridge
Stylus tip shape	Conical
Stylus tip material	Diamond
Stylus tip finish	Highly polished

Collectibility & Value

The ADC RQ-4 isn't collected so much as used. Turntable owners keep it on the shelf as a spare. As of current listings, a replacement RQ-4 sells for $26.95 USD, a price that reflects a functional spare part rather than a vintage artifact. There's no data on original pricing or production years, and no known common failures or maintenance quirks are documented. It was probably too simple to fail in interesting ways. If you own an ADC Q-4 cartridge, an RQ-4 stylus keeps it playing.