Grado Timbre Reference4 Phono Cartridge - High Output

What You Need to Know

What Is a Phono Cartridge?

A phono cartridge is the component at the end of your tonearm that reads the groove in your vinyl record. A tiny diamond tip — the stylus — traces the groove walls as the record spins, and the cartridge converts that physical movement into an electrical signal that your phono stage amplifies into music. The diamond profile, cantilever material, generator design, and body material all affect what you hear. At this level of the Timbre Series, every one of those elements has been refined to its highest expression within the Grado wood-body lineup.

The Reference4 — Top of the Timbre Series

Grado Labs has been making phono cartridges in Brooklyn, New York since 1953. The company is still family-owned, now in its third generation. The Timbre Series sits in the middle tier of Grado’s lineup — above the plastic-bodied Prestige Series and below the flagship Lineage Series. Within the Timbre range, the Reference4 is the top model, sitting above the Master4 and Sonata4.

The Reference4 shares the Master4’s American Osage wood body and machined boron cantilever. What separates it is the stylus: where the Master4 uses an elliptical diamond, the Reference4 uses a nude Shibata diamond — the most advanced stylus profile in the Timbre Series, and the same profile used in Grado’s flagship Lineage Series cartridges. At $1,500, the Reference4 is the Timbre Series at its most resolved. The High Output version at 4.0mV works with any standard MM phono input.

The Nude Shibata Diamond — What Makes It Different

The Shibata stylus profile was originally developed for four-channel (quadraphonic) playback in the 1970s, because quadraphonic records encoded high-frequency content — up to 45 kHz — that elliptical styli could not reliably track. To read this content accurately, the stylus needed to make finer, more precise groove wall contact. The Shibata profile achieves this through a narrow, elongated contact patch that follows the groove walls with exceptional precision at frequencies well beyond what elliptical styli can track.

In the Reference4, the Shibata diamond is nude: the diamond is mounted directly to the boron cantilever without an intermediate shank or bonded bushing. A nude stylus has less mass at the cantilever tip than a bonded equivalent, allowing faster, more accurate response to the groove modulations. The combination of nude construction and Shibata profile gives the Reference4 its extended high-frequency specification (10 Hz–60 kHz) and the precise, low-distortion tracking that distinguishes it from the elliptical-diamond models below it in the Timbre range.

American Osage Wood Body

The Reference4’s body is machined from American Osage wood — one of the densest native North American hardwoods, shared with the Master4. Osage’s density provides natural acoustic damping for the generator assembly, absorbing vibrations from the stylus rather than reflecting them back as distortion. The Timbre Series uses different woods for different models: American Maple for the Opus4, Mediterranean Olive for the Platinum4 and Sonata4, and American Osage for the Master4 and Reference4 — the two upper-tier models that demand the most acoustically controlled housing environment.

Machined Boron Cantilever

The cantilever connects the stylus to the generator. Its job is to transmit groove modulations as accurately as possible with minimal added mass or resonance. The Reference4 uses a machined boron cantilever — the stiffest and lightest cantilever material in the Timbre Series. Boron’s high stiffness-to-mass ratio pushes its resonant frequency well above the audible range, so the cantilever’s own mechanical resonances do not color the signal. “Machined” means the cantilever is precision-formed rather than drawn or extruded, ensuring consistent geometry from unit to unit. This is the same cantilever material used in the Master4, and it is one of the reasons both models sit above the Sonata4 and Platinum4 in the Timbre hierarchy.

6N OCC Copper with Cryogenic Treatment and Internal Damping

The Reference4’s internal signal path uses 6N OCC (Ohno Continuous Casting) copper — the highest purity level in the Timbre Series. OCC copper is produced in a continuous casting process that eliminates grain boundaries along the wire’s length. 6N means six-nines purity: 99.9999% copper with minimal trace contaminants. The result is lower resistance variation, better signal transmission, and more consistent channel balance.

Two additional refinements are applied to the Reference4 that distinguish it within the Timbre lineup: cryogenic treatment of the stylus assembly and internal signal path, and internal damping within the cartridge body. Cryogenic treatment involves cooling the components to extremely low temperatures (−196°C) and slowly returning them to ambient — a process that relieves stress in the material structure, improves conductivity, and enhances mechanical stability. Internal damping reduces residual vibration within the body itself. Together, these treatments contribute to the Reference4’s lowered noise floor, improved channel separation, and the greater resolution it offers over the Master4.

Grado Moving Iron Flux-Bridger Generator

Like all Grado cartridges, the Reference4 uses the moving iron (MI) flux-bridger generator. Stationary coils, twin magnet system, moving iron element attached to the cantilever. Four magnetic gaps for high efficiency and low inductance. Extremely low moving mass. The High Output version’s 55mH inductance and 660Ω DC resistance reflect the higher number of coil windings used to achieve 4.0mV output — compatible with any standard MM phono input at 47kΩ. No step-up transformer or MC gain is required.

Who the High Output Version Is For

The Reference4 High Output produces 4.0mV — the same output level as a standard moving magnet cartridge. Any phono stage or amplifier with an MM input at 47kΩ is compatible. If your phono stage has only an MM input, this is the version to choose. If your phono stage has MC gain capability, the Low Output version’s simpler signal path (fewer coil windings, lower inductance) is worth considering.

What the Experts Say

Note: The Reference4 was announced April 9, 2026. No scored reviews exist at time of writing. Replace with scored reviews as they are published (expected May–June 2026).

Pairing the Reference4 High Output

• Phono Preamplifier. The Reference4 HO is compatible with any quality MM phono stage at 47kΩ. At this level, the phono stage is a meaningful part of the chain — a high-quality MM or switchable MM/MC phono preamplifier will do justice to the Reference4’s resolution. Browse our Phono Preamplifiers.
• Turntable. The Reference4’s 9.6g weight and 20 μm/mN compliance pair well with medium-mass tonearms (approximately 8–15g effective mass). Confirm tonearm/cartridge resonance compatibility before purchasing. Browse Turntables.
• Consider the Low Output Version. If your phono stage has MC gain capability (approximately 58–60 dB at 47kΩ), the Reference4 Low Output’s simpler coil path and lower inductance is worth comparing. Call us and we can help you decide which version suits your system.
• Step Down: Timbre Master4. The Master4 shares the same Osage body and boron cantilever at a lower price, but uses an elliptical diamond rather than Shibata. The key question is whether the Shibata upgrade justifies the step up for your system and listening priorities.
• Step Up: Lineage Series. Above the Timbre Series, Grado’s Lineage models use Brazilian Ebony wood, sapphire or boron cantilevers, and nude Shibata diamonds in low-output configurations. The Reference4 is the highest Timbre expression; the Lineage Statement is the next architecture above it. Browse Phono Cartridges.
• Record Cleaning. A nude Shibata diamond deserves clean records. Browse Record Cleaning Machines.

Features & Specifications

Nude Shibata Diamond — The Top Stylus Profile in the Timbre Series

The Shibata profile makes a finer, more precise groove wall contact than an elliptical stylus, enabling accurate tracking of high-frequency content to 60 kHz. “Nude” means the diamond is mounted directly to the boron cantilever without an intermediate shank — reducing tip mass for faster, more accurate response. The Shibata diamond is the defining upgrade of the Reference4 over the Master4.

Machined Boron Cantilever

Precision-machined boron tube. High stiffness-to-mass ratio pushes resonant frequency well above the audible range. Shared with the Master4; the most rigid cantilever material in the Timbre Series.

American Osage Wood Body

One of North America’s densest hardwoods. Provides natural acoustic damping for the generator assembly. Shared with the Master4; used for the two upper-tier Timbre models.

6N OCC Copper with Cryogenic Treatment and Internal Damping

6N (99.9999%) OCC copper in the internal signal path — the highest purity in the Timbre Series. Cryogenic treatment of stylus assembly and signal path components reduces mechanical stress and improves conductivity. Internal body damping reduces residual resonance. These three refinements together distinguish the Reference4 from the Master4.

Moving Iron Flux-Bridger Generator — Twin Magnet System

Stationary coils, twin magnet system, moving iron element. Four magnetic gaps. Extremely low moving mass. Compatible with standard MM phono input at 47kΩ. No SUT or MC gain required.

Specifications — High Output

• Output voltage: 4.0mV @ 5 CMV (45 degrees)
• Frequency response: 10 Hz–60 kHz
• Channel separation: Average 30 dB (10–30 kHz)
• Input load: 10k–47kΩ
• Inductance: 55mH
• DC resistance: 660Ω
• Stylus: Nude Shibata diamond
• Cantilever: Machined boron
• Body: American Osage wood
• Internal signal path: 6N OCC copper, cryogenic treatment, internal damping
• Cartridge weight: 9.6g
• Recommended tracking force: 1.6–1.9g
• Compliance: 20 μm/mN
• Compatible phono input: Standard MM (47kΩ) — no SUT or MC gain required

What’s in the Box

• Grado Timbre Reference4 High Output phono cartridge ×1
• Stylus guard
• Mounting hardware (screws and nuts)

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