ZXY-6731 Audio Isolation Transformer - 150:600 / 600:600, 40Vrms, 4000VAC, 20-Pin Dual-Inline Solder Pins, Multi-Fin Industrial Housing

1. Product Name

ZXY-6731 Audio Isolation Transformer. 40 Vrms, dual-row solder pin terminal array, multi-fin industrial housing. Available in Type A (150:600-40Vrms) or Type B (600:600-40Vrms).

Identification. The faceplate is printed with ZXYAUDIO / TRANSFORMERS, followed by the impedance configuration, then the model code ZXY-6731. The configuration information printed on the label is the basis for distinguishing the two models: 150:600-40Vrms is Type A, 600:600-40Vrms is Type B. Apart from the label, the rest of the body is completely identical, so the label is the only external way to distinguish them after unboxing; please verify the label before installation.

Both models are passive devices with encapsulated construction. No power pins, no bias circuitry, no active stages: the signal enters the primary, passes through the magnetic circuit, exits from the secondary and is isolated from the primary side. That is all it does, which is why the device has no quiescent current and introduces no noise of its own.

2. Features

Two impedance configurations on one platform. 150:600 for impedance matching, 600:600 for 1:1 line isolation — one certified design covers both circuit applications.

40 Vrms high-level voltage rating. Rated for high-level audio with robust overload capability, distinguishing it from line-level-only devices.

150 Hz - 600 Hz linear transmission band. Optimized for voice and low-to-mid frequency audio, covering the frequency range actually used by telemetry, intercom, and broadcast systems.

Electrical isolation. Breaks ground loops and suppresses common-mode noise between the two sides.

Low insertion loss, phase-stable. Signal level and timing remain consistent within the specified band.

Multi-fin industrial housing. Convection cooling ribs conduct heat away from the encapsulated core and windings.

Flame-retardant molded housing. Heavy-duty case, epoxy encapsulated, UL94 V-0 rated.

4000 VAC dielectric strength. Primary-to-secondary withstand voltage far exceeds the 40 Vrms operating voltage.

Operating temperature range -40 °C to +105 °C. Industrial-grade temperature coverage for outdoor and enclosed equipment.

20-pin dual-row solder pin array. Primary 1-5, secondary 1-10, auxiliary 1-5, with wired leads for direct connection to chassis harnesses.

The thermal path is worth mentioning because it is uncommon in signal transformers. A 40 Vrms audio level is far above line level, and a device continuously handling this level dissipates more heat than a line-level transformer; the cooling fins provide an escape path for this heat, and the epoxy encapsulation conducts heat from the windings to the housing. The result is that the device body remains within its rated temperature range even inside an enclosed chassis with no airflow.

3. Advantages

Multiple impedance options in a single design. No need for a second certified device when a second circuit application requires re-certification, reducing project lead time.

Signal integrity maintained with minimal loss. Low insertion loss and low phase shift ensure level and timing remain unchanged after passing through the transformer.

Low distortion. Accurate transmission with professional-grade precision, rather than deliberate tone shaping.

Rugged industrial-grade construction. Withstands thermal stress and mechanical vibration, operating reliably in environments where desktop-grade devices fail.

Hermetic epoxy encapsulation. Environmentally friendly and performance-consistent throughout its service life.

Built for demanding environments. Suitable for professional and industrial systems where failures are not everyday events.

The 4000 VAC primary-to-secondary withstand rating is more significant than the 40 Vrms operating rating suggests. An isolation barrier capable of withstanding four thousand volts is not there for normal operation; its purpose is to ensure that if a fault occurs on one side — such as a power supply short circuit, a lightning surge on a telemetry line, or incorrect mains wiring — dangerous potentials are not transferred to the other side. In broadcast and industrial installations, this isolation is both a safety requirement and a noise reduction measure.

4. Applications

Broadcast and telemetry audio. Clean, balanced audio transmission in broadcast consoles, field production units, and telemetry systems.

Voice and intercom transmission. Impedance matching and isolation for clear, reliable voice communication in intercom and paging systems.

Studio signal routing and preamplifiers. Balanced audio routing, preamplifiers, and mixing consoles that maintain signal integrity and reduce noise.

Industrial audio isolation and grounding. Electrical isolation and ground loop elimination in industrial audio systems and control environments.

The common thread is that two devices are connected by a long cable, and they are grounded separately. Telemetry lines are routed between buildings, intercom lines connect rooms on different distribution panels, and industrial audio lines pass by drives and contactors. In each case, the transformer is placed at the boundary, and the two impedance options allow the same device to either match a low-impedance source to a 600-ohm input (Type A) or transparently interface with a 600-ohm line (Type B).

5. Application Specifications

5.1 Performance Characteristics

5.2 Specification Table

5.3 Terminal Assignment (20-Pin Dual-Row Array)

6. Quality and Testing Assurance

Every unit is manufactured under controlled processes and verified before shipment. Each product undergoes audio signal isolation and 40 Vrms integrity testing, so units that fail the isolation barrier or withstand voltage rating cannot leave the production line.

This product carries CCC, CE, RoHS, and UL compliance certifications. The housing is made of flame-retardant material, and the epoxy encapsulant is rated UL94 V-0, the flame-retardant rating on which the UL declaration is based.