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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 | 60 mm Max Height | 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: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 20230803003.
The EI66x28 is a 50 Hz encapsulated audio isolation transformer built on a compact EI66 laminated core. It is wound for a 220 V AC, 50 Hz primary and provides a 23 V ±5% no-load output on the blue-blue winding, with a no-load current of 55 mA MAX and a no-load loss of 4.5 W MAX.
The winding is housed in a flame-retardant nylon bobbin, fully encapsulated and vacuum varnish impregnated, and mounted on a zinc-plated steel bracket for panel installation. In amplifier equipment the transformer isolates the audio signal and power paths, suppressing hum, noise and common-mode interference so that the signal path stays stable and clean.
2. Feature
Reliable encapsulated construction — fully encapsulated winding with vacuum varnish impregnation for moisture resistance and long-term reliability.
Pure copper winding — high-grade pure copper wire for stable, low-loss transmission.
Flame-retardant nylon bobbin — durable insulation with high heat resistance (UL file E41938).
Compact EI66 core — high-permeability H50N electrical steel laminations delivering optimised magnetic flux and low loss.
Insulated lead wires — flexible silicone lead wires, 250 mm ±10 mm, with tinned copper terminations.
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 clean audio performance.
Low frequency stability — designed and tested for stable operation at 50 / 60 Hz.
3. Advantage
High common-mode rejection — the isolation barrier separates the audio stage from power and ground noise, removing ground-loop hum.
Enhanced dielectric strength — AC 1500 V primary-secondary and AC 1000 V for primary-core and secondary-core, giving ample safety margin in amplifier power sections.
High insulation resistance — ≥100 MΩ MIN (DC 500 V / 1 min) keeps isolation stable over the product lifetime.
Low no-load current and loss — 55 mA MAX and 4.5 W MAX reduce heat build-up and standby energy consumption.
Stable performance, low noise — consistent electrical output with low audible noise in continuous operation.
Direct factory supply — manufactured in-house by a supplier with 26 years of transformer experience (since 1998), giving competitive pricing and stable lead times.
OEM and custom solutions — custom winding (turns ratio, impedance, inductance), custom dimensions, custom electrical specifications, and support from prototype to mass production.
Custom winding covers turns ratio, impedance and inductance; custom dimensions are matched to the space available; custom electrical specifications cover voltage, frequency and power. Prototype builds are supported through to mass production.
4. Application
The EI66x28 is intended for audio amplifier and low-frequency isolation duty, including:
Audio amplifier and power isolation stages — the transformer sits between the mains side and the audio supply, breaking the ground loop that causes hum.
Public address systems, active speakers and professional audio equipment — line-level and supply isolation in equipment that must stay quiet at low signal levels.
Instrumentation, control panels and measurement equipment — isolating a 50 / 60 Hz supply where a ground loop would otherwise corrupt a measurement.
Isolated 50 / 60 Hz signal and supply interfaces — a compact isolation barrier for interfaces that must not share a common reference.
OEM audio equipment — a fully encapsulated isolating transformer that fits a standard panel cut-out.
5. Application Specifications
Electrical performance. All values as listed in the specification for approval:
| 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 PRI-SEC | AC 1500 V | 1 mA, T = 1 s, 50 Hz |
| Dielectric strength PRI-CORE | AC 1000 V | 1 mA, T = 1 s, 50 Hz |
| Dielectric strength SEC-CORE | AC 1000 V | 1 mA, T = 1 s, 50 Hz |
| Insulation resistance PRI-SEC | ≥100 MΩ MIN | DC 500 V / 1 min |
Construction and outline dimensions. All dimensions are in millimetres (mm).
| Item | Specification |
|---|---|
| Core type | EI66 laminated core, H50N electrical steel sheets |
| Maximum height | 60 mm |
| Width | 30.5 mm |
| Bracket thickness | 0.8 mm |
| Frame thickness | 0.5 mm |
| Lead wire length | 250 mm ±10 mm, flexible silicone insulated |
| Encapsulation | Vacuum varnish impregnated, fully encapsulated |
| Mounting | Zinc-plated steel bracket, panel mount |
Material list:
| No. / Description | Specification | UL File No. |
|---|---|---|
| Bobbin | Nylon 101 | E41938 |
| Tape | CT-280 | E165111 |
| Wire | 2UEW-F | E344055 |
| Jumper wire | UL AWG22 | E189674 |
| Core | H50N electrical steel sheets | — |
| Frame | 0.5 mm thickness steel | — |
| Bar tin | Sn-Cu | — |
| Varnish | E962 | E228349 |
6. Quality & Testing Assurance
Every unit is electrically tested before shipment. The inspection items and test conditions are:
HI-POT insulation — PRI-SEC AC 1500 V (1 mA, 50 Hz, 1 s).
Insulation resistance — PRI-SEC ≥100 MΩ (DC 500 V / 1 min).
No-load voltage — 23 V ±5%.
Test condition — 1 mA, T = 1 s, 50 Hz.
The EI66 series is manufactured to meet EU standards in an ISO 9001 certified factory and is CE and RoHS compliant. Certification covered: CCC, CE, RoHS, UL and ISO 9001. Each transformer is identified with its own product label and is packed for safe transport, so that performance is repeatable from the first sample to volume 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 | 60 mm Max Height | 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 | 60 mm Max Height | 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 | 60 mm Max Height | 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 | 60 mm Max Height | 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 | 60 mm Max Height | 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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