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250V 100mA 6.3V 2A CT HT Valve transformer

A superb quality multipurpose transformer for any valve project or experimentation.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

A single 250V 100mA secondary for use with a silicon rectifier.
Heater winding 6.3V at 2A centre tapped.

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Construction

Separate primary and secondary sections for safety.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Connecting wire – stand up only

High quality PVC 600V
Primary and HT : 24AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

1Kg for the clamp version

Compliance

Built and tested to safety standard BS EN 61558-1 2005

* The 0-190V winding produces around 260V when rectified – great for EL84-based amps. There’s the full 160mA available, so you can run a pair in push-pull, parallel SE or even in stereo.
* The 0-275V winding gives typically 360V when rectified – designed for octal power valves (EL34, 6L6, etc) in more powerful SE amps (15W or so). This also has 160mA available, so it’s also perfect for push-pull amps with lower-power valves, such as the EL84 and 6V6.
* The 190-275V winding is also available, and gives around 115V when rectified. This is a ‘freebie’ – a side effect of the two main values I chose – but it adds a really useful option to use in amp projects…

…Switchable B+!

With these asymmetrical windings, there are three combinations available to run into the rectifier bridge. This means you can use a 3-position rotary switch to get a switchable B+ supply in your amp. With the ratios given you get:
* Full power from the 0-275V winding
* Half-power from the 0-190V winding
* 1/10th power from the 190-275V winding
It’s like an ultra-simple version of Power Scaling (seeKevin O’Connor’s London Power Website for the cost of a switch! With 3A at 6.3V available for heaters, this is a very flexible transformer for amps up to 18W or so in output.

Dimensions & info

It’s 78mm wide, 70mm deep and 64mm tall, with standard solder lugs for all primary and secondary connections. It’s available in a lay-down style, to drop through a rectangular cut-out in the chassis (such as that on AC04 small and AC02 medium chassis). The rectangular cut-out should be 54x49mm, and the four 4mm mounting bolts are on 64x51mm centres. This type has a dual 120/240V primary winding.

Primaries

2 x 120V

Secondaries

0 – 190V – 275V @ 160mA
Heater winding 6.3V at 3A centre tapped.

Steel

High quality silicon steel
Hand laminated for the best stacking factor, and accuracy.

Construction

Separate primary and secondary sections for safety.

Winding wire

High quality enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Weight

1.22Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

Dual 120V/240V primaries, 2A heater supply; ideal for preamps and amps up to 5W output
This power transformer is  designed as a replacement or alternative for those popular amp circuits that specify the Hammond 269EX or 369EX power transformer. It has dual 120V/240V primary windings and two secondary windings. The high voltage winding is 190-0-190V rated at 80mA. In a typical circuit, this will produce a B+ of around 250V after smoothing.
The heater supply secondary is a non-CT 6.3V rated at 2A. That makes it perfect for an amp using two 12AX7s and a single EL84 or 6V6, or a channel-switching preamp using as many as six 12AX7 valves.

Dimensions & info

It’s 78mm wide, 62mm deep and 64mm tall, with standard solder lugs for all primary and secondary connections. It’s supplied in a ‘drop through’ (also known as lay-down) style. This mounts through a rectangular cut-out in the chassis (such as that in the AC02 medium) and AC04 small chassis. The rectangular cut-out should be 54x49mm, and the four 4mm mounting bolts are on 64x51mm centres.

Primaries

2 x 120V

Secondaries

190 – 0 – 190V @ 80mA
Heater winding 6.3V at 2A centre tapped.

Steel

High quality silicon steel
Hand laminated for the best stacking factor, and accuracy.

Construction

Separate primary and secondary sections for safety.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Weight

1.01Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

A superb quality mains transformer for any valve project. Originally designed to power a Mullard 5-10 Mono amplifier. It will happily power a stereo Mullard 3-3 amplifier alone, without the pre-amp.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.
US primary dual 120V.

Secondaries

HT winding 300V – 0 – 300V at 100mA DC
Heater winding 6.3V at 2A centre tapped.
Rectifier winding 6.3V at 1A

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Electrostatic Screen

Solid copper sheet providing the best RF screening possible between primary and secondaries.

Connecting wire

High quality PVC 600V
Primary and HT : 24AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

2.3Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

Designed to power a Mullard 5-10 Stereo amplifier using a single GZ34 or two EZ81 rectifiers.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

HT winding 300V – 0 – 300V at 200mA
Heater windings 6.3V at 4A centre tapped.

Rectifier winding 6.3V at 2A tapped at 5V at 2A.

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Electrostatic Screen

Solid copper sheet providing the best RF screening possible between primary and secondaries.

Connecting wire

High quality PVC 600V
Primary and HT : 22AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

3Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

Designed to power a Mullard 5-20 Mono amplifier to the Mullard specification.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

HT winding 410V – 0 – 410V at 180mA DC
Heater windings 6.3V at 4A centre tapped, 6.3V at 2.5A centre tapped.
Rectifier winding 5V at 3A

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Electrostatic Screen

Solid copper sheet providing the best RF screening possible between primary and secondaries.

Connecting wire

High quality PVC 600V
Primary and HT : 22AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

3Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

A superb quality mains transformer for any valve project. Originally designed to power a Mullard 3-3 Mono amplifier.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.
US primary voltage dual 120V.

Secondaries

HT winding 300V – 0 – 300V at 80mA DC
Heater winding 6.3V at 1A centre tapped.
Rectifier winding 6.3V at 1A

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Electrostatic Screen

Solid copper sheet providing the best RF screening possible between primary and secondaries.

Connecting wire – stand up only

High quality PVC 600V
Primary and HT : 24AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

1.5Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

A superb quality mains transformer for any valve project or experiment.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

HT windings 2 separate 0 – 250V @ 80mA These may be connected in series to give 250 – 0 – 250V @ 80mA or parallel to give 0 – 250V @ 160mA
Heater winding 6.3V at 2A centre tapped.
Rectifier winding 5V at 2A

https://primarywindings.com/2020/12/21/the-very-versatile-pwht01-and-pwht02-transformer/

Steel

High quality 400-50 silicon steel.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Weight

1.4Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

A superb quality mains transformer for any valve project or experiment.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

HT windings 2 separate 0 – 250V @ 80mA These may be connected in series to give 250 – 0 – 250V @ 80mA or parallel to give 0 – 250V @ 160mA
Heater winding 6.3V at 2A centre tapped.
Rectifier winding 6.3V at 2A
Heater windings in parallel can give 6.3V @ 4A

https://primarywindings.com/2020/12/21/the-very-versatile-pwht01-and-pwht02-transformer/

Steel

High quality 400-50 silicon steel.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Weight

1.4Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

A superb quality mains transformer for any valve project.
Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

HT winding 300V at 320mA DC
Heater winding 6.3V at 3A centre tapped.

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Connecting wire – stand up only

High quality PVC 600V
Primary and HT : 24AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

2.07Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

This transformer was inspired by the EAR 834P RIAA pre-amplifier, but may be used in many other designs.

Being a pre-amp the spec on this transformer is very conservative. It is designed with very low flux density, and high quality M6 laminations, meaning the magnetising current is tiny, and the stray flux is very small.
This would normally be enough for a pre-amplifier transformer, but we went further, and added a bright copper flux band, to reduce any stray flux down to almost nothing.
The fact that the magnetising current is so small ensures the mag current waveform is still quite sinusoidal meaning less harmonics to be generated. This is much better than a typical toroidal transformer, where the mag current is high, and is very distorted, generating lots of harmonics.
The copper band makes the transformer look great.

Proudly made in the United Kingdom

Primaries

European primary voltages, 220V, 230V, 240V and 250V.

Secondaries

A single 250V 80mA secondary for use with a silicon rectifier.
Heater winding 6.3V at 2A centre tapped.

Steel

High quality Grain Orientated M6 0.35mm.
Hand laminated for the best stacking factor, and accuracy.

Construction

Separate primary and secondary sections for safety.

Winding wire

Double coated Grade 2 enamelled copper wire.
Wound using CNC winders for highly accurate wire placement and turns count.

Connecting wire – stand up only

High quality PVC 600V
Primary and HT : 24AWG UL1015
Secondary LT : 20 AWG UL1015

Weight

1Kg

Compliance

Built and tested to safety standard BS EN 61558-1 2005

Part of the PWHT2000 series mains transformers

Primaries:

European: 220V – 250V in 10V steps.

Secondaries:

Screen:

Solid copper screen between the primary and secondary. For superior safety and reduction in EMI conduction from primary to secondary.

Wires:

18 AWG Alpha wire 15 ” lead length.

 

Part of the PWHT2000 series mains transformers

Primaries:

European: 220V – 250V in 10V steps.

Secondaries:

Screen:

Solid copper screen between the primary and secondary. For superior safety and reduction in EMI conduction from primary to secondary.

Wires:

18 AWG Alpha wire 15 ” lead length.

 

Part of the PWHT2000 series mains transformers

Primaries:

European: 220V – 250V in 10V steps.

Secondaries:

Screen:

Solid copper screen between the primary and secondary. For superior safety and reduction in EMI conduction from primary to secondary.

Wires:

18 AWG Alpha wire 15 ” lead length.

 

Part of the PWHT2000 series mains transformers

Primaries:

European: 220V – 250V in 10V steps.

Secondaries:

Screen:

Solid copper screen between the primary and secondary. For superior safety and reduction in EMI conduction from primary to secondary.

Wires:

18 AWG Alpha wire 15 ” lead length.

 

Part of the PWHT2000 series mains transformers

Primaries:

European: 220V – 250V in 10V steps.

Secondaries:

Screen:

Solid copper screen between the primary and secondary. For superior safety and reduction in EMI conduction from primary to secondary.

Wires:

18 AWG Alpha wire 15 ” lead length.