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EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount
EI66*28 encapsulated audio isolation transformer. Model/Part No. EI66*28, ZXY Part No. B2348, core size EI66x28, specification 20230803003.
- 型号
- EI66*28
- 型号（2）
- EI66*28
- 引线
- 250 ±10 mm 硅胶
Phone:+86 13554723725
Email:rhea@zxycoil.com
Description
1. Product Name
EI66*28 encapsulated audio isolation transformer. Model/Part No.: EI66*28, ZXY Part No.: B2348, core size: EI66x28, specification No.: 20230803003.
The EI66x28 is a 50 Hz encapsulated audio isolation transformer featuring a compact EI66 laminated core structure. Its primary winding is designed for 220 V AC, 50 Hz, with the blue-blue winding providing a 23 V ±5% no-load output voltage, a maximum no-load current of 55 mA, and a maximum no-load loss of 4.5 W.
The windings are encapsulated in a flame-retardant nylon bobbin, fully potted and vacuum-impregnated, and mounted on a galvanized steel plate bracket for panel mounting. In amplifier equipment, this transformer isolates the audio signal from the power path, suppressing hum, noise, and common-mode interference to ensure a stable and clean signal path.
2. Product Features
Reliable Encapsulated Construction — Windings are fully potted and vacuum-impregnated for moisture resistance, ensuring long-term reliability.
Pure Copper Windings — Made with high-quality pure copper wire for stable transmission and low losses.
Flame-Retardant Nylon Bobbin — Durable insulation with high heat resistance (UL file No. E41938).
Compact EI66 Core — High-permeability H50N electrical steel laminations for optimized flux and low losses.
Insulated Leads — Flexible silicone leads, 250 mm ±10 mm in length, with tinned copper terminals.
Steel Mounting Bracket — 0.5 mm frame with 0.8 mm bracket for standard panel mounting.
Audio Signal Isolation — Effectively isolates noise and hum for pure audio performance.
Low-Frequency Stability — Designed and tested for stable operation at 50 / 60 Hz.
3. Product Advantages
High Common-Mode Rejection — The isolation barrier separates the audio stage from power and ground noise, eliminating ground-loop hum.
Enhanced Dielectric Strength — Primary-secondary AC 1500 V, primary-core and secondary-core AC 1000 V, providing ample safety margin for amplifier power sections.
High Insulation Resistance — ≥100 MΩ MIN (DC 500 V / 1 minute), ensuring stable isolation performance throughout the product's service life.
Low No-Load Current and Low Loss — Maximum 55 mA and maximum 4.5 W, reducing temperature rise and standby power consumption.
Stable Performance and Low Noise — Consistent electrical output during continuous operation with low audible noise.
Factory Direct Supply — Manufactured in-house by a supplier with 26 years of transformer experience (since 1998), offering competitive pricing and reliable lead times.
OEM and Custom Solutions — Customizable windings (turns ratio, impedance, inductance), custom dimensions, and custom electrical specifications, with full support from samples to mass production.
Custom windings cover turns ratio, impedance, and inductance; custom dimensions can be matched to available space; custom electrical specifications cover voltage, frequency, and power. Full support is provided from sample prototyping to mass production.
4. Application Areas
The EI66x28 is suitable for audio amplifier and low-frequency isolation applications, including:
Audio Amplifiers and Power Isolation Stages — The transformer sits between the mains side and the audio power supply, breaking ground loops that cause hum.
Public Address Systems, Powered Speakers, and Professional Audio Equipment — Provides line-level and power isolation in equipment that must remain quiet at low signal levels.
Instrumentation, Control Panels, and Measurement Equipment — Isolates 50 / 60 Hz power to prevent ground-loop interference with measurement results.
Isolated 50 / 60 Hz Signal and Power Interfaces — Provides a compact isolation barrier for interfaces that cannot share a common reference ground.
OEM Audio Equipment — Fully encapsulated isolation transformer that fits standard panel cutouts.
5. Application Specifications
Electrical performance. All values as listed in the submitted specification:
| Parameter | Specification | Test Condition |
|---|---|---|
| Rated Primary Voltage | 220 V AC, 50 Hz | — |
| No-Load Current | 55 mA max | — |
| No-Load Loss | 4.5 W max | — |
| No-Load Output Voltage (Blue-Blue) | 23 V ±5% | — |
| Dielectric Strength (Primary-Secondary) | AC 1500 V | 1 mA, T = 1 s, 50 Hz |
| Dielectric Strength (Primary-Core) | AC 1000 V | 1 mA, T = 1 s, 50 Hz |
| Dielectric Strength (Secondary-Core) | AC 1000 V | 1 mA, T = 1 s, 50 Hz |
| Insulation Resistance (Primary-Secondary) | ≥100 MΩ MIN | DC 500 V / 1 minute |
Construction and outline dimensions. All dimensions are in millimeters (mm).
| Item | Specification |
|---|---|
| Core Type | EI66 laminated core, H50N electrical steel |
| Maximum Height | 60 mm |
| Width | 30.5 mm |
| Bracket Thickness | 0.8 mm |
| Frame Thickness | 0.5 mm |
| Lead Length | 250 mm ±10 mm, flexible silicone insulated |
| Encapsulation Method | Vacuum impregnation, fully potted |
| Mounting Method | Galvanized steel bracket, panel mount |
Bill of materials:
| Item / Description | Specification | UL File No. |
|---|---|---|
| Bobbin | Nylon 101 | E41938 |
| Tape | CT-280 | E165111 |
| Magnet Wire | 2UEW-F | E344055 |
| Lead Wire | UL AWG22 | E189674 |
| Core | H50N electrical steel | — |
| Frame | 0.5 mm thick steel plate | — |
| Solder Bar | Sn-Cu | — |
| Insulating Varnish | E962 | E228349 |
6. Quality and Testing Assurance
Every unit is electrically tested before shipment. Inspection items and test conditions are as follows:
HI-POT Withstand Insulation — Primary-secondary AC 1500 V (1 mA, 50 Hz, 1 second).
Insulation Resistance — Primary-secondary ≥100 MΩ (DC 500 V / 1 minute).
No-Load Voltage — 23 V ±5%.
Test Conditions — 1 mA, T = 1 second, 50 Hz.
The EI66 series is manufactured in an ISO 9001-certified facility in accordance with European standards and complies with CE and RoHS requirements. Certifications covered: CCC, CE, RoHS, UL, and ISO 9001. Each transformer carries an individual product label and is packaged and shipped in a safe manner, ensuring consistent and repeatable performance from first article samples to mass production.
Specifications
| 型号 | EI66*28 |
|---|---|
| 型号（2） | EI66*28 |
| 引线 | 250 ±10 mm 硅胶 |
| 空载电流 | 55 mA MAX |
| 空载输出电压 | 23 V ±5%（蓝-蓝） |
| 额定初级 | 220 V AC / 50 Hz |
| 零件编号 | B2348 |
| 磁芯 | EI66 H50N 叠片 |
| 品牌 | ZXY |
| 认证 | CCC / CE / RoHS / UL / ISO 9001 |
| 产品类型 | 封装音频隔离变压器 |
Only supplied parameters are shown. Please confirm any unlisted electrical performance, test conditions, tolerances and customization options with our engineers. The final specification sheet takes precedence.
Product Images & Drawings
View the available product images and drawings below. Click to open the original. Customized products are subject to the agreed specifications and drawings.
Downloads
No specification sheet has been uploaded for this model yet. Use the inquiry form below to request parameters, dimension drawings or sample information.
Selection & Customization Requirements
To help confirm a suitable model and specification, please provide:
- Your equipment, application, operating environment and temperature range.
- As applicable: inductance, turns ratio or impedance, operating frequency, voltage, current and insulation requirements.
- Size limits, mounting method, pin spacing, and any existing drawings or reference samples.
- Sample quantity, estimated order volume and desired delivery date.
Frequently Asked Questions
Common procurement questions about EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount.
What is EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount?
EI66*28 encapsulated audio isolation transformer. Model/Part No. EI66*28, ZXY Part No. B2348, core size EI66x28, specification 20230803003.
Can EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount be customized to our specifications?
Yes. Shenzhen ZhiXiangyuan Electronics Co., Ltd. provides OEM/ODM services. Inductance, turns ratio, current rating, core material, size and terminal style can all be customized according to your drawings or samples.
What is the MOQ and lead time for EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount?
MOQ is negotiable based on the specific model and order quantity. Typical lead time is 1-3 weeks for standard items and 2-4 weeks for customized orders. Contact our sales team for an exact quotation.
Do you provide samples of EI66*28 Encapsulated Audio Isolation Transformer - 220 V 50 Hz Primary | 23 V ±5% No-Load Output | H50N EI66 Laminated Core | Max Height 60 mm | Chassis Mount?
Yes, samples are available for evaluation before bulk orders. Please send us your requirements and shipping details to request samples.
What is the model number of this product?
The model number is EI66*28. Custom model numbers can be assigned for OEM orders.
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