ADC RQ-3

Dropping the needle on a clean vintage pressing gives a satisfying click. This little blue stylus is part of that.

Overview

The ADC RQ-3 is a replacement stylus for the ADC Q-3 and Q-4 cartridges. It is just the needle assembly, made to bring a mid-20th century phono cartridge back to life. Audio Development Company (ADC) was founded in 1935 by two Bell Labs engineers, so signal fidelity was not new to them. The RQ-3 is not flashy. It is functional, precise, and built to last.

Owners report that a fresh RQ-3 brings back clarity and warmth that worn styli can't match. One review of a compatible version says it delivers “better musical accuracy, improved tonal balance and higher sound quality” - big praise for a part smaller than your pinky nail. A fresh tip traces the grooves better than a dull or damaged one, which is easier on your records. The stylus has a highly polished conical diamond tip. That is not the most advanced profile by modern standards, but it is durable and forgiving on older pressings. The housing is blue, so it is easy to spot on a crowded shelf or in your tonearm.

The RQ-3 itself has no firm production dates. It belongs to an ADC lineup with 68 documented models, which points to a serious engineering effort behind their cartridge line. Third-party suppliers still make exact replacements today.

Specifications

Manufacturer	ADC (Audio Development Company)
Product type	Replacement stylus (needle) for a phono cartridge
Stylus tip shape	Conical diamond
Stylus tip condition	Highly polished
Compatible Brand	ADC
Compatible Model	ADC Q-3, Q-4 cartridges
Compatible Speeds	33 & 45 RPM
MPN	117-d6 (Pfanstiehl number)
Country of Origin	Japan

Collectibility & Value

New Old Stock (NOS) units of compatible replacement styli, such as the Pfanstiehl 117-D6, are available and actively traded among vinyl enthusiasts who maintain vintage gear. Current prices for these replacements run from $15.95 to $39.16 USD, depending on seller and condition. No original pricing data exists for the ADC RQ-3 itself, but accurate third-party equivalents keep these older cartridges practical and affordable to service. There is no documented information on common failures or maintenance specific to the RQ-3 stylus. Given its simple mechanical role, problems typically come only from physical damage or extreme wear.