OEM FACTORY Precision Instrumentation & Audiophile Division

R-Core Transformers & Precision Audio Power Solutions

Engineered for high-end DACs, phono preamplifiers, tube amplifiers, and sensitive medical instruments. Featuring continuous-wound Nippon Steel silicon strip cores, twin-bobbin physical isolation, annealed OFC copper perimeter flux shielding, and ultra-low stray magnetic leakage (< 5 mG).

15 VA – 500 VA Range < 5 mG Stray Field 4,000V AC Hi-Pot Isolation 115V / 230V Universal Primary ≤ 35K Temp Rise (Class F)
Request Custom Winding RFQ Inspect AutoCAD Blueprints WhatsApp Direct (+86 139 0560 5991)
Factory Submittal Specs ISO 5457 CAD
  • Zero Cut-Gap Core: Continuous slit silicon steel strip without stamped lamination joints.
  • Twin Bobbin Symmetry: Independent primary and secondary bobbins minimize capacitive noise.
  • OFC Copper Shield: Continuous annealed copper band wraps the outer magnetic perimeter.
  • Teflon Lead Wires: High-temperature silver-plated PTFE leads with custom color coding.
Factory Contact: Hefei XinHuan • 139-0560-5991

Electromagnetic Architecture

Why R-Core Is the Ultimate Choice for Audiophile & Precision Power

Combining the compact circular magnetic circuit of a toroidal transformer with the physical isolation of an EI transformer, the R-Core design eliminates mechanical vibration, stray EMI, and capacitive mains noise.

Continuous Wound Core

Wound from a continuous strip of high-permeability Nippon Steel grain-oriented silicon steel. With zero cut-gaps and no stamping burrs, magnetic reluctance is uniform, completely eliminating mechanical hum.

Twin Bobbin Isolation

Primary and secondary coils are physically wound on separate bobbins mounted on opposite legs of the core. Inter-winding capacitance is slashed to < 15 pF, blocking high-frequency mains EMI from reaching audio circuits.

OFC Copper Flux Shield

Every XinHuan R-Core transformer is encircled by an outer perimeter annealed Oxygen-Free Copper (OFC) foil shielding band. This contains eddy currents and suppresses stray magnetic radiation to < 5 mG.

Ultra-Low Exciting Current

The seamless circular cross-section ensures uniform flux distribution. No-load exciting current is less than 10% of traditional EI transformers, resulting in remarkable efficiency (> 93%) and a full-load temperature rise ≤ 35K.

Objective Benchmark

Technical Architecture Comparison: R-Core vs. Toroid vs. EI

Why audio designers and instrumentation engineers choose XinHuan R-Core transformers over traditional alternatives.

Technical Parameter XinHuan R-Core Transformer Toroidal Transformer Traditional EI Transformer
Stray Magnetic Flux Leakage < 5 mG (1/10th of EI core) 10 – 25 mG 50 – 120 mG (High leakage)
Inter-Winding Capacitance < 15 pF (Physically separated bobbins) 80 – 220 pF (Coils overlap, passes HF noise) 40 – 90 pF
Immunity to Mains DC Offset High (Uniform circular reluctance) Extremely Vulnerable (Saturates & hums easily) Moderate
Mechanical Vibration & Buzz Zero (Continuous un-slit strip, no loose sheets) Low under clean AC; hums on dirty mains Noticeable (Lamination chatter & gap buzz)
Primary / Secondary Insulation 4,000V AC (Heavy physical barrier) 2,500V – 3,500V AC (Tape barrier) 2,500V – 3,000V AC
No-Load Exciting Current < 10% of EI Transformer Very Low (< 12%) High (Air gap loss across joints)
Full-Load Temperature Rise ≤ 35K (Class F Insulation) ≤ 45K ≤ 55K
Best Suited Applications Audiophile DAC, Tube Preamp, Phono, Medical IT High-power PA amps, Inverters Low-cost consumer appliances
FACTORY CERTIFIED DRAWINGS

Interactive AutoCAD Submittal Blueprints

Monochrome vector drawings adhering to ISO 5457 sheet coordinates, pure white paper-space background, and verified DIN mechanical dimensions. Switch tabs below to inspect assembly footprints, wiring schematics, and tube output stages.

ISO 5457 Vector Download .SVG Request Custom .DWG
XinHuan R-Core Transformer Mechanical Assembly and Mounting AutoCAD Submittal Drawing DWG-XH-RC-01
DWG-XH-RC-01 Key Details: View A (Front Section with twin bobbins & OFC copper band), View B (Top Plan Footprint with mounting centers A × B), View C (Leakage comparison vs EI), Table 1 (15VA – 500VA dimensional schedule).
Standard: IEC 61558-1 / UL 5085 • 100% Hi-Pot 4.0 kV
XinHuan R-Core Transformer Electrical Wiring Schematic DWG-XH-RC-SCH-02
DWG-XH-RC-SCH-02 Key Details: Universal primary coils with 230V series jumper (P2+P3) and 115V parallel jumper (P1+P3 & P2+P4). Faraday electrostatic shield grounding terminal. Dual center-tapped secondary coils S1-S2 and S3-S4.
PTFE Silver-Plated Teflon Leads • Color Coded
XinHuan High-Fidelity Audio Output Transformer Tube Amplifier Blueprint DWG-XH-RC-OPT-03
DWG-XH-RC-OPT-03 Key Details: View A (4P3S interleaved sandwich winding structure), View B (0.08mm anti-saturation air gap for 300B / KT88 SE Class A), View C (Push-Pull schematic with 43% Ultra-Linear taps & secondary 4Ω/8Ω/16Ω).
Core: Nippon Steel Z11 (27Z130) • Bandwidth: 15Hz – 45kHz (±1dB)

Product Catalog Matrix

Standard R-Core Production Range & Dimension Schedule

Direct from our Hefei precision transformer workshop. All models are available with standard voltages or fully customized secondary taps.

Model Rated Power Dimensions (L×W×H) Mounting Centers (A×B) Weight Standard Secondary Voltage Options Action
XH-R15 15 VA 72 × 62 × 42 mm 62 × 46 mm 0.45 kg 9V-0-9V / 12V-0-12V / 15V-0-15V (Dual 0.83A) Configure
XH-R30 30 VA 78 × 68 × 46 mm 68 × 52 mm 0.65 kg 15V-0-15V / 18V-0-18V / 24V-0-24V (Dual 1.0A) Configure
XH-R50 50 VA 86 × 76 × 52 mm 76 × 60 mm 0.95 kg Dual 18V / Dual 24V / Tube 250V+6.3V Multi-Tap Configure
XH-R80 80 VA 96 × 84 × 58 mm 84 × 66 mm 1.35 kg Dual 18V / Dual 24V / Dual 28V (Dual 1.8A) Configure
XH-R100 100 VA 102 × 90 × 62 mm 90 × 72 mm 1.65 kg Dual 24V / Dual 30V / Dual 36V (Dual 2.0A) Configure
XH-R150 150 VA 115 × 100 × 70 mm 100 × 80 mm 2.30 kg Tube B+ 280V-0-280V + 5V 3A + Dual 6.3V 3A Configure
XH-R200 200 VA 125 × 110 × 76 mm 110 × 88 mm 2.95 kg Dual 28V / Dual 32V / Dual 36V (Dual 3.5A) Configure
XH-R300 300 VA 140 × 125 × 88 mm 125 × 100 mm 4.20 kg Dual 35V / Dual 40V / Dual 45V (Dual 3.75A) Configure
XH-OPT-SE30 30 W (OPT) 96 × 85 × 82 mm 80 × 68 mm 2.65 kg Pri 3.5kΩ/5.0kΩ SE • Sec 0-4-8Ω (300B / KT88) Configure
XH-OPT-PP50 50 W (OPT) 105 × 92 × 90 mm 88 × 76 mm 3.40 kg Pri 5.0kΩ P-P + 43% UL • Sec 0-4-8-16Ω (EL34 / KT88) Configure
Need ratings between 300VA – 1000VA, custom multi-taps, or balanced electrostatic copper foil shielding? Submit Custom Request →

Heritage Craftsmanship

Specialty Vacuum Tube & Hi-Fi Audio Transformer Family

Directly ported from XinHuan's boutique domestic workshop (Taobao Shop 117526627). Decades of coil winding mastery dedicated to tube audio enthusiasts and professional recording studios.

Single-Ended (SE) 15Hz – 45kHz

Single-Ended Output Transformers

Custom-engineered for single-ended Class A triode amplifiers (300B, 2A3, KT88, 211, 845). Features 4-section primary / 3-section secondary interleaved winding, imported Nippon Steel Z11 (27Z130) laminations, and precision anti-saturation paper air gaps withstanding up to 120mA quiescent DC plate current.

  • • Primary Impedances: 2.5 kΩ / 3.5 kΩ / 5.0 kΩ
  • • Secondary Taps: 4 Ω / 8 Ω (16 Ω optional)
  • • THD: < 0.15% @ 1kHz
Push-Pull (PP) 43% Ultra-Linear

Push-Pull Output Transformers

Engineered for high-power push-pull tube amplifiers (EL34, KT88, 6550, KT120, 6L6GC). Equipped with exact 43% screen grid Ultra-Linear (UL) taps and 5-section primary interleaving to maintain pristine phase linearity and wide dynamic range.

  • • Primary Impedances: 3.4 kΩ / 5.0 kΩ / 6.6 kΩ P-P
  • • Frequency Bandwidth: 12Hz – 55kHz (±1dB)
  • • Power Ratings: 30W / 50W / 100W
Inductors & Chokes Low DCR

Power Supply Filter Chokes

High-inductance, low DC resistance smoothing chokes designed for CLC & LC power supply filters. Wound with heavy oxygen-free copper wire and vacuum varnish impregnated to eliminate mechanical buzzing under high pulsating DC ripple.

  • • Inductance: 5H / 10H / 15H @ 150mA – 350mA
  • • Working Voltage: 500V – 1,000V DC
  • • Epoxy potted black steel can or open frame

OEM / ODM Capabilities

Custom Winding Specifications Tailored to Your Schematic

Whether you are an audio manufacturer creating a flagship DAC product line or an EPC consultant specifying medical isolation transformers, XinHuan offers complete bespoke winding services with rapid prototype delivery in 3–5 business days.

Multi-Rail Secondaries

Up to 8 isolated secondary rails for independent digital, analog, and clock supplies.

Shielded Potting Cans

CNC-milled aluminum or cold-rolled steel black epoxy potted housings for ultimate EMI rejection.

Class H Insulation

UL-certified Class B (130°C), Class F (155°C), or Class H (180°C) thermal systems.

100% Routine Testing

Every unit tested for 4,000V AC hi-pot dielectric withstand, leakage current, and ratio accuracy.

Workshop Technical Checklist

Core Silicon Grade Nippon Steel 23Z140 / Baosteel B23R080 (0.23mm thickness)
Conductor Material 99.99% Oxygen-Free Copper (OFC), 2UEW / 2PEW Grade
Dielectric Withstand 4,000V AC (Pri – Sec), 2,000V AC (Pri – Core) for 60s
Lead Wire Standard UL 1332 PTFE Teflon silver-plated wire, 300mm standard length
Electrostatic Shielding 0.10mm annealed copper foil between bobbins with grounding tab
Varnish Impregnation Vacuum Pressure Impregnation (VPI) with Class F baking resin
Standards Compliance IEC 61558-1, IEC 61558-2-4, UL 5085-1/2, CE, RoHS, REACH
INSTANT CRM SUBMISSION

Request Custom R-Core / Audio Transformer Quote

Direct communication with Hefei XinHuan engineering team. Formal technical drawings and quote delivered within 2 hours.

Strict NDA & confidential schematic protection. Direct factory response from Hefei, China.

Technical Guidance

Frequently Asked Questions — R-Core & Audio Transformers

Toroidal transformers have primary and secondary windings directly overlapping across the entire core circumference. This creates high inter-winding capacitive coupling (often 80 to 200 pF), which allows high-frequency RF noise, spikes, and switching transients from the AC mains to bleed straight into the audio circuitry. In contrast, an R-Core transformer uses two physically separated bobbins located on opposite legs of the core, lowering inter-winding capacitance to under 15 pF and acting as a natural high-frequency noise filter.

Modern AC mains often carry small DC offset voltages (caused by asymmetric household appliances like hair dryers). Toroidal cores have virtually zero air gap and saturate extremely quickly under slight DC offset, causing loud mechanical humming and acoustic buzz. The R-Core's circular cross-section and twin symmetrical bobbin geometry distribute flux evenly, providing substantially higher tolerance against DC saturation and remaining completely whisper-silent.

We support both prototype evaluations (MOQ = 2 pieces) for engineering development and bulk production orders (100 to 5,000+ pieces). Custom engineering samples are typically completed within 3 to 5 business days from CAD submittal sign-off, with expedited global air express shipping.

Yes. All XinHuan precision transformers are manufactured in strict compliance with IEC 61558-1 (General Safety Requirements), IEC 61558-2-4 (Isolation Transformers), UL 5085-1/2, CE, RoHS, and REACH. Every transformer undergoes 100% routine dielectric withstand testing at 4,000V AC before dispatch.