| Description | The LoNo Audio Power Transformer Line of toroids is designed for demanding high-end audio amplifier applications. Characterized by its noise performance under adverse line conditions, these transformers remain quiet even at 10% high line with 250 mV DC voltage in the mains. They are encapsulated in spun aluminum cases with a textured black finish. They also have tight regulation, for applications where off load voltages are a concern; and very low temperature rise, which is useful for high ambient operating conditions, or where instantaneous power - in excess of rating – is required. |
Approvals
 | UL and CE recognized and carry the respective labels. UL506, UL1411 for class B (130°C) insulation systems. Materials and construction is verified by CSA File No. LR-84566-11 to C22.2 #66-1988 to IEC65 (EN60065). Primary and secondary leadouts are double insulated UL3173 type. Transformers are intended for use in end-product equipment where the suitability of the combination is to be determined by the appropriate approval authority. |
| Inputs | Dual 115 VAC windings, parallel connected for 115 VAC, or series for 230 VAC at 50 / 60 Hz. See schematics for more details. |
| Insulation | Primary to secondary: Polyester tape, class B (130°C). 50 Hz transformers, four layers minimum. Meets the test requirement of >4 kV for one minute. |
| Noise | Maximum NC (Noise Criterion dB at 1 meter) 11 under adverse mains conditions: 10% high line and 250 mV DC.For more information see Measuring Acoustic Noise Emitted by Power Transformers presented at the 109th Covention of the Audio Engineering Society. This preprint was prepared by Menno van der Veen and the reseach staff at PLITRON. |
| Temperature Rise | Maximum 50°C. At maximum rated load, continuous. |
| Outputs | See ratings table for output voltage and current ratings. Secondaries are bilfilar wound where possible for optimum coupling, and theoretically perfect balancing. |
| Output Tolerance | Better than 3% at full load. |
| Load Regulation | See ratings table. Figures given are for 60 Hz operation, for 50 Hz operation figures increase slightly. |
| Mechanical | All units in this series are fully encapsulated in spun aluminum cases with black textured finish. Embedded threaded inserts are used to mount these units with a single bolt from the base. See mechanical table for details. |
| Leads | Standard: Stranded tinned copper wire (CSA TEW, UL-1015, 105°C). Stripped 6 mm. Finished length: 200 mm. |
| Thermal Protection | Dual normally closed thermal switches in series with each primary, open at 130°C, auto resetting. UL, CSA listed components. |
| Magnetic Shielding | To attenuate stray magnetic fields. Multiple layers of grain oriented silicon steel laminated between insulation. Wrapped around circumference of transformer under case. |
Low Noise