EI41-66-80W 80W Audio Power Transformer AC 220V 50Hz to Dual AC 12V-0V-12V 3.3A Shielded Chassis Mount

1. Product Name

MYT-66-80W is the model number printed on the chassis label and repeated on the specification panel, and it is also the sole part code in the bill of materials: an 80 W audio power transformer with a 220 V 50 Hz primary and a center-tapped 12 V secondary. The same label also indicates the lead wire colors for input and output as well as the manufacturer's name, so a unit can be identified by the label alone without a drawing.

The panel calls it an audio power transformer, which is an accurate description: a mains power transformer designed for installation inside an audio product, neither an output transformer nor a signal isolation device. In the signal sense, no winding is in the audio path; its role is to generate the DC power rails required by the amplifier. Catalogs typically list a series, and the panel shows multiple units of the same construction under the OEM and ODM headings, so the model number is the fixed point and the windings are the variable item.

2. Functional Description

A linear audio power supply begins with the transformer because the power rails must be isolated from the mains and the voltage must be stepped down before rectification. This product accepts 220 V 50 Hz input and provides two 12 V half-windings around a center tap, so either two rectifiers and a pair of reservoir capacitors can be used to form a dual supply, or the two half-windings can be paralleled for a single 12 V rail with doubled current. The 3.3 A is the winding current of the secondary at 80 W power; its distribution between the two half-windings depends on the rectifier configuration, which is not specified in the material.

3. Construction and Shielding

The construction of this type of part follows the conventional form, and the photographs show everything. High-permeability EI silicon steel laminations are stacked through a molded bobbin, the windings are placed behind paper and film insulation layers on the bobbin, and the core-and-coil assembly is enclosed in a metal shell that is open on the bobbin face. That shell is the shield: it encloses the magnetic circuit around the coil and isolates the leakage field from the rest of the chassis. A galvanized frame wraps the shell and carries the mounting brackets, with slotted holes at both ends for fastening the part to the chassis bottom or side wall.

4. Lead Wires and Terminals

The lead wires are the interface, and they are color-coded. Two red leads carry the 220 V primary and come pre-fitted with Faston crimp terminals, so they can be connected to a switch or terminal block without soldering. Three leads carry the secondary: blue to one end, black to the center tap, and blue to the other end, so the panel writes the output as 12 V-0-12 V. The leads exit the bobbin through a breakout comb to keep them separated. Their length and wire gauge are not stated anywhere in the material.

5. Electrical Specifications

The specification panel is the complete electrical description, in four lines: model MYT-66-80W, input AC 220 V 50 Hz (red-red leads), output AC 12 V-0-12 V 3.3 A (blue-black-blue leads), and rated power 80 W. The enclosure label repeats the same four items. There are no regulation values, efficiency, no-load current, temperature rise, insulation class, dielectric test voltage, or insulation resistance, so the part can only be specified by its winding and nothing else.

5.1 Published Data and Its Implications

6. Bench Measurement

One photograph shows the part connected to a power analyzer: 230.07 V rms input, 0.142 A rms current, 32.41 W, power factor 0.987, frequency 50.00 Hz, with oscilloscope waveforms of primary voltage and current in the background. The room's mains voltage is higher than the 220 V rating, and 32.41 W is about 40% of the 80 W rating, so this is a partial-load reading rather than a full-load test. It shows the part drawing a reasonable current at near-unity power factor; it does not give efficiency, regulation, or temperature rise.

7. Mechanical Data

None of the ten panels includes a dimensioned drawing, and no dimensions are marked anywhere. What is visible is the enclosure shape, the bracket positions and their slotted holes, and the fact that the front of the wire frame is open. The enclosure outline, mounting hole spacing and diameter, can top height, lead length, and weight are all missing, and every one of them is required before drilling the chassis.

8. OEM and ODM Supply

The panel presents the part as one build in a custom series: a set of units of the same construction under an OEM and ODM heading, with factory-direct bulk supply noted below. This is a statement about how the part is sold, not a second specification, and the group panel carries no dimensions or ratings. Treat the series as evidence that other windings are available on the same construction on request, and treat the MYT-66-80W as the only build described by the figures.

9. Quality and Compliance

The compliance panel shows four marks: CCC, CE, RoHS, and UL, under the heading International Quality Certification and Standards. RoHS is a substance restriction rather than a safety certification, and the UL mark does not carry the word "Recognized" that component certifications usually carry. None of the four marks is accompanied by a certificate number, standard reference, or test report, and the same panel carries no dielectric or insulation data.

10. Feature

80 W shielded can construction. The rating is the winding and the can is the shield, both visible in the photographs rather than existing only on the label.

Center-tapped secondary. Three output leads, blue, black, and blue, provide two 12 V half-windings around a common tap, or 24 V between the two outer leads.

Pre-wired and color-coded. Red for the 220 V primary, blue and black for the secondary, with Faston crimp terminals pre-fitted on the primary leads.

EI silicon steel core. High-permeability EI laminations, annotated on the construction panel, with the winding on a molded bobbin behind film insulation.

Chassis mounting. Galvanized frame with slotted brackets at both ends, so the part can be bolted to the chassis bottom or side wall without an additional bracket.

One code, one build. MYT-66-80W is printed on the enclosure label and the specification panel, so the part can be ordered by code without a drawing.

11. Advantage

It isolates the mains from the audio ground. The primary and secondary are isolated by the winding itself, so the audio ground is not connected to the mains conductor.

One part provides a dual supply. The center tap allows one transformer to supply two rails, which is smaller and cheaper than two separate parts plus an extra chassis hole.

The enclosure serves two functions. It shields the coil and acts as the mechanical interface, so the part needs no separate shield cover or mounting bracket.

The leads are the connector. Faston terminals on the primary and flying leads on the secondary mean no terminal block is needed on the transformer body.

Published model number. Unlike parts sold only by description, this part can be quoted, cross-referenced, and re-ordered by code, which is exactly what OEM builds require.

12. Specifications

Values are transcribed from the supplier panel. Where a value is missing, the cell reads "Not stated"; where the material does not mention a characteristic, the gap is explicitly marked rather than filled. Rows marked "Derived" are calculations based on published values.

13. Application

The following uses are what the material points to, with notes on why the center-tapped 12 V winding suits each one. These describe the sales scenarios for the part, not qualification of any specific batch.

Linear amplifier power supply. The 12 V-0-12 V secondary is a common form for a small dual supply feeding an audio power stage.

Active mixers and consoles. Where low-voltage and symmetrical rails are needed simultaneously from a single mains connection in one chassis.

Powered speakers. One mains transformer in the cabinet, with rectifiers and capacitors on the amplifier board behind it.

Preamplifiers and converters. Where the 80 W margin is far above the load and the shield is the reason for choosing this part.

Desktop and test equipment. Dual supplies for op-amp circuits, where the shielded can prevents magnetic fields from disturbing nearby signal wiring.

OEM manufacture of the above products. The panel shows the part as one winding in a custom series, so other primary and secondary combinations are normal use of the series.

14. Ordering

Send the application and the required voltage rails first, then the specific parameters. A valid inquiry should include the mains voltage and frequency, the voltage and current of each secondary, whether the two half-windings are used as a dual supply or in parallel, and the ambient temperature and mounting position. Request an outline drawing with hole center spacing, lead length and wire gauge, insulation class, dielectric test voltage, and temperature rise, because none of these are published. If your solution is close to this product, use MYT-66-80W as the starting point for a quote and list the differences.

Compliance note: the panel shows CCC, CE, RoHS, and UL, and presents all four as certifications covering the part. But no certificate number, standard reference, or test report is attached, and the UL mark does not carry the word "Recognized." This is reported here only as marks and claims, not as verified certification. A mains transformer is a safety-critical part, so request the certificates and reports for the standards required by your product before finalizing the design.

Brand/Manufacturer: ZXY, Shenzhen Zhi Xiang Yuan Electronics Co., Ltd. http://www.zxycoil.com