RY-800VA 800VA Toroidal Audio Power Transformer AC 220V 50Hz Dual Secondary Centre Bolt Mount

1. Product Name

RY-800VA is the model on the name plate, and the plate carries the whole identity of the part: primary AC 220 V 50 Hz on red leads, secondary 0 V to 38 V on yellow-yellow and 0 V to 38 V on blue-blue, a 130 degrees C thermal marking and a date stamp. The same plate carries the CCC, CE and WEEE marks and the double square insulation symbol. There is no drawing in the material, so the plate is the datasheet.

The panels describe the same part three ways: a toroidal transformer in a range from 50 VA to 1000 VA, an audio grade transformer, and an 800 VA custom build. They are one product line seen from three angles. The part itself is a mains transformer, not an output transformer: the second aries feed rectifiers and reservoir capacitors, and the audio signal never passes through it.

2. What It Does

A toroid is chosen for two reasons in audio equipment. The core is a continuous ring, so the magnetic path has no gap and the field it throws outside the part is small compared with an EI stack of the same rating; that is what allows it to be bolted inside a chassis near the signal stage. And the winding covers the whole core, so for the same rating the part is lower and wider than a stacked lamination, which suits a slim case. Two separate secondaries on two colours give two isolated feeds, so a dual rail can be built with two bridges and one transformer.

3. Construction and Winding

The build is visible in the close-ups. A seamless grain-oriented silicon steel core is wound with oxygen-free copper in a radial lay, so the turns stand on edge around the ring rather than being layered flat, which is what keeps the winding short and the resistance low. Paper and film insulation separate the windings, the leads are brought out as flying tails, and the whole toroid is wrapped in a transparent high-voltage insulation film that is visible in the close-up as a glossy skin over the copper.

4. Centre Bolt Mounting

Mounting is a single centre bolt. A black steel top plate is pressed over the toroid, a zinc-plated bolt passes through it and through the core, and a nut with a rubber cushion and a steel washer clamps the assembly down. The rubber is there to break the metal path between the bolt and the plate, which is what keeps chassis vibration out of the core and the core out of the chassis. The toroid stands on a black base plate with four slotted holes at the corners for fixing screws, and the plate is shaped so the part can be turned to bring the leads where they are needed.

5. Electrical Specifications

The specification panel gives five lines and the name plate repeats them. Model RY-800VA, 800 VA. Input AC 220 V 50 Hz on red-red. Output 1, AC 0 V to 36 V on yellow-yellow. Output 2, AC 0 V to 36 V on blue-blue. Thermal protection, a 130 degrees C cutoff. The plate on the unit itself reads 0 V to 38 V for both secondaries on three of the photographs and 0 V to 36 V on one, which is the one figure in the material that does not agree with itself.

5.1 The published set

6. Measured on the Bench

One photograph shows the part on a power analyzer with its primary connected: 229.7 V rms, 0.151 A rms, 34.70 W, power factor 0.996, with an oscilloscope trace of the primary voltage and current behind it. The mains in that room was above the 220 V rating and 34.70 W is about 4 percent of the 800 VA rating, so this is a light-load reading rather than a full-load test. It shows the part drawing a sane current with the current trace clean and in phase; it does not give an efficiency, a regulation or a temperature rise.

7. Audio Performance and the Range

The audio claims on the panels are qualitative: ultra-low magnetic stray field, low mechanical hum, high current capability and fast dynamic response. None of them is given a number or a test condition, and the panel that carries them shows a 50 W 24 V unit of the same range rather than the 800 VA part, so they describe the construction and the range rather than this rating. The range itself is published as 50 VA to 1000 VA with single and dual output and OEM or ODM builds, and two of the group labels read EEEIO-C50VA and EEEIO-C100VA, which is a different prefix from RY-800VA.

8. Packaging and Delivery

Supply format is a carton with a moulded EPE foam insert, described as a drop-tested heavy duty carton. The photograph shows six units standing in the foam in one box, which is how the range is shipped rather than a statement about the quantity per carton for this rating. No quantity, carton size or weight is given.

9. Quality and Compliance

The compliance panel shows four marks, CCC, CE, RoHS and UL, under a heading about international quality certifications and standards, with a line across the top that presents all four as covering the part. The name plate itself carries CCC, CE, the double square insulation symbol, a damp-proof umbrella and the WEEE bin. No certificate number, standards reference or report is reproduced with any of them, and the UL mark is shown without the Recognized wording that a component approval normally carries.

10. Feature

800 VA in a toroid. Two secondaries on one core, wound to the rating, with the low profile a toroid gives for the same power.

Two isolated secondaries. Yellow-yellow and blue-blue, each 0 V to 36 V or 38 V depending on the plate, so a dual rail comes from one part.

130 degrees C cutoff. A thermal element inside the winding, marked on the plate and stated on the specification panel as the protection.

Oxygen-free copper, radial lay. The winding stands on edge around the core, which keeps the turns short and the resistance low.

Grain-oriented core. A seamless silicon steel ring with no gap in the magnetic path, which is what keeps the stray field down.

Centre bolt with rubber cushion. One bolt through the core clamps the part to the chassis, with a rubber cushion and steel washer between bolt and top plate.

11. Advantage

It fits inside the chassis. A toroid of this rating is low and wide, and the small stray field means it can sit near the input stage without inducing hum.

One part, two rails. Two isolated secondaries remove the second transformer a dual rail supply would otherwise need.

The bolt is the mount. One hole in the floor plate and four anti-rotation screws, instead of a cradle or a bracket.

The rubber cushion is the quiet. Breaking the metal path between bolt and plate keeps core vibration out of the chassis.

A published rating range. The same construction is offered from 50 VA to 1000 VA, so a different rail is a winding change rather than a new design.

12. Specifications

Values are transcribed from the supplier panels and the name plates. Where a figure is absent the cell reads Not stated. Where two plates disagree both readings are kept and the conflict is named in the note column rather than resolved here.

13. Application

The uses below are the ones the material points at, with a note on why a toroid of this rating fits each. They describe where the part is sold, not a qualification of any one build.

Power amplifier supplies. The part in the photograph sits on an amplifier floor plate feeding the reservoir bank.

Preamplifiers and DAC supplies. Where the stray field and the mechanical hum matter more than the rating.

Active loudspeakers. One transformer inside the cabinet, with the rectifiers and capacitors on the amplifier board.

Studio and instrument amplifiers. A dual rail from two secondaries, with the 130 degrees C cutoff as the thermal backstop.

Industrial and control panels. Where a low profile and a bolted mount suit a crowded enclosure.

OEM builds across the range. The same construction from 50 VA to 1000 VA, single or dual output, built to order.

14. Ordering

Send the rail you need first, then the numbers. A usable enquiry states the mains voltage and frequency, the secondary voltage and the current each winding has to carry, whether the two windings are used as separate rails or in series, the ambient and the mounting position. Ask which secondary voltage the price refers to, 36 V or 38 V, and ask for the diameter, the height, the weight, the bolt thread, the base plate hole size, the current per winding, the regulation and the test voltage, because none of those is published. If the build is close to this one, quote RY-800VA as the starting point and list the differences.

On compliance: the panel shows CCC, CE, RoHS and UL and presents all four as covering the part. No certificate number, standards reference or report is reproduced with any of the marks, and the UL mark appears without the Recognized wording. They are reported here as marks and declarations, not as verified approvals. A mains transformer is a safety critical part, so ask for the certificate and the report for the standard your product has to meet before the design is fixed.

Brand / manufacturer: ZXY, Shenzhen Zhixiangyuan Electronics Co., Ltd. http://www.zxycoil.com