ZXY DU124 Microphone Transformer, Fly-Lead Type, 20 Hz - 20 kHz, Turns Ratio 1:4 / 1:7 / 1:12, Stacked EI Core, 16.5 x 12.0 x 25.0 mm, Four Pre-Tinned Leads

1. Product Name

ZXY DU124 microphone transformer, fly-lead type, in the 1:4, 1:7 or 1:12 turns ratio. Stacked EI lamination core, high-dielectric-strength yellow Mylar tape over the winding, four pre-tinned leads with UL AWM style insulation at a nominal 40 ± 2 mm, body 16.5 x 12.0 x 25.0 mm, frequency range 20 Hz to 20 kHz.

Overview. The part is built around a stacked EI lamination core, 7.5 mm across the lamination, with the winding occupying 13.0 mm of the 25.0 mm body height. The body measures 16.5 mm in front view and 12.0 mm in side view, so what it takes from a layout is a narrow footprint and a tall column.

The four leads come off the bobbin rather than out of pins. That is the whole point of this form: it can be routed into a microphone body, a flying harness or an existing assembly after the mechanical design is already fixed, where a pinned part would force a board revision.

2. Feature

Isolation that protects the upstream stage. the transformer couples the signal without a conductive path, so a fault or a DC offset on one side cannot take out the output stage that feeds it.

Voice and data coupling. wound for signal coupling in speech and data paths rather than for power transfer, which is what the 20 Hz to 20 kHz window is there to cover.

20 Hz to 20 kHz frequency range. the full audio band, so the part can sit in a microphone line, a preamp input or a line-level interface without being the element that limits bandwidth.

Ground-loop hum rejection. the isolation breaks the loop formed when two pieces of equipment are earthed separately, which is where the AC hum in a signal chain usually comes from.

Balanced and unbalanced use. reduces external interference in either configuration, so the same part serves a balanced microphone run and an unbalanced line inside a chassis.

Fly-lead termination. four pre-tinned leads of 40 ± 2 mm instead of PCB pins, for wiring into a microphone body, a harness or an existing assembly where no footprint is available.

Low-distortion, wide-response winding. tuned to hold speech intelligibility and audio fidelity at the same time, which is the compromise a microphone transformer has to make.

Stacked EI lamination core. precision-stacked laminations, taped over with high-dielectric-strength yellow Mylar, so the winding is insulated from the core edge.

The detailed view shows the three things that carry the performance of this part: the leads are pre-tinned and insulated to UL AWM style, the core is stacked from laminations rather than solid, and the winding is covered by high-dielectric-strength yellow Mylar tape before the core goes on. That tape layer is what the 1500 V withstand rating is measured across.

3. Advantage

Three ratios, one series. 1:4, 1:7 and 1:12 cover step-up needs from a modest level lift to a high-ratio microphone match, so one qualified part family can cover a product range.

Wiring flexibility. a lead-out part can be routed after the mechanical design is fixed, which is rarely true of a pinned transformer on a board.

Documented electrical set. inductance, DC resistance and dielectric withstand are published per ratio at 25 °C, so the part can be specified against numbers rather than by ear.

Consistent dielectric margin. all three variants are rated at 1500 V with a 1 mA leakage limit over 60 s, so the isolation figure does not have to be re-qualified when the ratio changes.

Tape insulation over the winding. high-dielectric-strength Mylar between the winding and the core, which is the layer that carries the withstand rating.

Pre-tinned leads. ready to solder without stripping or tinning at the bench, with UL AWM style insulation on the lead.

Custom designs available. the winding can be adapted to a target ratio, level or footprint, with factory-direct supply and stock on the standard variants.

Read the schematic before wiring the part. RED and BLACK sit on one winding with the polarity dot on the BLACK side; BLUE and YELLOW sit on the other with the dot on the BLUE side. The drawing identifies the pairs and the dots but does not mark which winding is primary, so take the pairing from the drawing and confirm the intended side with the factory before fixing a wiring order in your own drawing.

4. Application

Microphones. lavalier, camera and instrument microphones, where the transformer sits inside the body or at the connector end of the lead.

Microphone preamplifiers and isolation modules. as the input transformer or the isolating element in a preamp or a channel module.

Audio systems. signal isolation and noise elimination in high-end loudspeakers, home theatre and car audio, where separate earths put hum into the signal.

Communication equipment. signal coupling for telephones, fax machines, IP voice terminals and modems, where the line side has to 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 between racks.

Both views show the same thing in practice: the transformer sits at the boundary between two circuits that must not share a conductor. In the breadboard it is the element between the source and the measured side; on the board assembly it is wired in on its leads beside the circuitry it isolates. Neither placement needs a footprint, which is why the same part appears in both.

5. Application Specifications

The specification below is the data declared for this model at 25 °C: product data, the electrical table per turns ratio, outline dimensions, and construction.

5.1 Product specification

5.2 Electrical specification, three turns-ratio variants

Inductance is measured at 1 kHz and 0.3 V as a minimum; DC resistance carries a ±15% tolerance; dielectric withstand is 1500 V with a 1 mA leakage limit held for 60 s.

5.3 Outline dimensions

5.4 Construction and lead-out wires

6. Quality & Testing Assurance

Every unit is checked against the limits below, taken from the same specification sheet that supplies the electrical table. The three turns-ratio variants share one set of limits except for the inductance and resistance values themselves.

Winding insulation uses high-dielectric-strength yellow Mylar tape, and the fly leads are pre-tinned for immediate soldering with UL AWM style insulation.

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