ZXY-EI16 Fly-Lead Microphone Transformer, Audio Isolation Type, 50 Hz - 20 kHz, 1:5 and 1:6 Turns Ratio, EI16 Laminated Steel Core, 16.5 x 14.5 x 14.5 mm

1. Product Name

ZXY EI16 fly-lead audio isolation microphone transformer, in the 1:5 version type B2456 or the 1:6 version type B2577. EI16 laminated steel core, insulated bobbin with a protective tape wrap over the coil, four colour-coded leads, 50 Hz to 20 kHz, body 16.5 mm long, 14.5 mm high and 14.5 mm deep.

Overview. The core is an EI16 lamination stack; the coil sits on an insulated bobbin inside the centre limb and is finished with a tape wrap. There are no pins, so what leaves the part is four leads: BLUE and YELLOW from the primary, RED and GREEN from the secondary.

A fly-lead part can be routed into a microphone body, a harness or an assembly after the mechanical design is fixed, where a pinned transformer would force a board revision. The two standard ratios cover the usual step-up requirements, so a custom winding is only needed when neither fits.

2. Feature

EI16 laminated steel core. the core is an EI16 lamination stack rather than a solid block, wound on an insulated bobbin and finished with a protective tape wrap over the coil.

50 Hz to 20 kHz frequency range. covers the whole audible band, so the part can sit in a microphone line or a coupling stage without setting the bandwidth limit itself.

Voice and data coupling. wound to couple voice and data signals between stages and across an isolation barrier, not to transfer power.

Two standard turns-ratio versions. 1:5 as type B2456 and 1:6 as type B2577, so the step-up can be matched to the circuit without a custom design.

Low distortion, wide-band design. the winding is designed to hold speech intelligibility and audio reproduction fidelity at the same time.

Dielectric withstand 1500 V. tested at a 1 mA leakage limit for 60 s, which is the barrier the isolation claim rests on.

Four colour-coded leads. BLUE and YELLOW on the primary, RED and GREEN on the secondary, with the phase end of each winding marked by a dot on the wiring diagram, so the part can be wired correctly without a meter.

Compact EI16 outline. 16.5 mm long, 14.5 mm high and 14.5 mm deep, small enough to sit inside a microphone body or beside a connector.

The side view shows the construction as a stack rather than a potted block: the two outer lamination limbs, the bobbin flange between them, and the coil face under its tape wrap. The leads leave the bobbin at the flange, which is what keeps the solder joint outside the winding window.

3. Advantage

Protects upstream equipment. as an isolating transformer it keeps the output stage of the preceding equipment from being damaged by what happens on the other side of the barrier.

Removes ground-loop hum. resolves the AC hum that appears when a system is earthed at more than one point, which is the usual cause of noise in a chain built from separately powered units.

Rejects interference both ways. reduces external interference pickup in balanced and in unbalanced transmission, so one part covers both wiring schemes.

Installation flexibility. the fly-lead construction adapts to a wide range of mounting and wiring scenarios, including positions where no footprint is available.

Audio quality held in balance. low distortion together with a wide frequency response keeps speech intelligible without flattening the audio band.

Custom builds and stock. customised designs are available, and the standard versions are supplied factory-direct with stock on hand.

Wire the part from the diagram, not from the wire order. BLUE is the phase lead on the primary and YELLOW its return; RED is the phase lead on the secondary and GREEN its return. The dots mark the phase end of each winding, so the two windings can be connected in the intended polarity rather than by trial.

4. Application

Professional audio equipment. lavalier microphones, camera microphones, instrument microphones, microphone preamplifiers and audio isolation modules.

Audio systems. signal isolation and noise elimination for high-end loudspeakers, home theatre systems and car audio.

Communication equipment. signal coupling for telephones, fax machines, VoIP terminals and modems, where the line side must stay isolated from the equipment side.

Industrial and broadcast systems. audio signal isolation and transmission in public-address and conference systems, including runs between rooms and racks.

Both views are of the same body from the lead side, and they show what a layout has to allow for: the leads leave upwards from the bobbin, so the part needs clearance above the flange rather than a footprint under it. That is the reason this construction is chosen for microphone bodies and harness assemblies.

5. Application Specifications

The specification below is the data declared for this model: general data, the electrical table per type at 25 °C, outline dimensions, and the lead assignment.

5.1 General specification

5.2 Electrical specification, two turns-ratio versions, 25 °C

Inductance is measured at 1 kHz with a 0.3 V test signal as a minimum; DC resistance carries a tolerance of plus or minus 15 percent; dielectric withstand is 1500 V with a 1 mA leakage limit held for 60 s. Winding 1 is the primary, the microphone side; winding 2 is the secondary, the console side.

5.3 Outline dimensions

5.4 Lead wire and winding assignment

6. Quality & Testing Assurance

The limits below are the acceptance limits the specification sheet states for both standard types. They share one set of limits except for the inductance and resistance values themselves.

Winding insulation is the insulated bobbin plus a protective tape wrap over the coil, and the leads are colour-coded so the windings can be identified without a meter.

Brand / manufacturer: ZXY, Shenzhen Zhixiangyuan Electronics Co., Ltd. and Huizhou Zhixiangyuan Technology Co., Ltd. http://www.zxycoil.com