1750R Hammond PP Übertrager Traynor 98694 A1301 Yorkville

Hammond 1750R – 100 W output transformer for Yorkville and Traynor

The Hammond 1750R is a large paper-wound push-pull output transformer providing 2 kΩ plate-to-plate and secondary taps for 4, 8 and 16 Ω. Hammond documents it for Yorkville or Traynor reference 98694 and comparison reference A1301.

Its low primary impedance is intended for high-current push-pull stages. The exact valve type and valve count depend on the particular Yorkville or Traynor circuit and must not be inferred from the 100 W rating alone.

Suitable applications

• Yorkville and Traynor amplifiers using documented reference 98694
• Replacement applications around comparison reference A1301
• Parallel push-pull stages requiring approximately 2 kΩ
• Correctly designed stages using four EL34, 6CA7 or 6550 valves in total
• Total loudspeaker loads of 4, 8 or 16 Ω
• Guitar and bass amplifiers in the 100 W transformer class

Technical data

Product type

Push-pull guitar- and bass-amplifier output transformer

Model

Hammond 1750R

Documented manufacturer application

Yorkville or Traynor

Documented references

98694 and A1301

Primary impedance

2 kΩ plate-to-plate with centre tap

Secondary impedances

4, 8 and 16 Ω

Transformer power rating

100 W

Amplifier topology

Push pull or parallel push pull

Winding type

Paper winding

Primary inductance

Approx. 4.84 H at 1 kHz, 1 V and open secondary

Blue-to-brown primary DC resistance

Approx. 25.72 Ω

Black-to-orange secondary DC resistance

Approx. 0.222 Ω across the complete secondary winding

Black-to-green secondary inductance

Approx. 16.20 mH

Black-to-yellow secondary inductance

Approx. 31.28 mH

Black-to-orange secondary inductance

Approx. 58.48 mH

Primary leakage inductance

Approx. 11.37 mH at 1 kHz, 1 V and short-circuited secondary

Frequency response

50 Hz to 12 kHz, 0/-1 dB referenced to 1 kHz

Distortion

Less than 1% at 50 Hz under the documented test conditions

Dielectric test

2,250 V RMS

Temperature range

-40 to +105 °C

Lead length

At least approximately 229 mm or 9 inches

Dimensions

Approx. 95.2 × 100.0 × 115.8 mm maximum

Mounting dimensions

Approx. 76.2 × 71.5 mm

Mounting slots

Approx. 5.2 × 9.5 mm

Hammond shipping weight

Approx. 3.18 kg

Manufacturing note

Made in Canada according to the current component drawing

Primary leads

Brown

First primary connection to one plate or plate group

Red

Primary centre tap to B+

Blue

Second primary connection to the opposite plate or plate group

Secondary leads and drawing conflict

Assignment supported by the component label and measurement table

Black common, green 4 Ω, yellow 8 Ω and orange 16 Ω

Conflicting large circuit diagram

The current PDF graphic shows the colour names in reverse order and should not be used as the sole wiring reference

Required verification

Confirm the marking on the delivered part, resistance between leads and the applicable original circuit

Selection for parallel push-pull

A 2 kΩ primary load is relevant to high-current output stages or several parallel output valves. Determine the correct valve count from the plate and screen voltage, quiescent current, operating class and intended output.

Where four output valves are used, verify every quiescent current individually. Individual control-grid stoppers and normally individual screen-grid stoppers support stable current sharing.

Safety notes

Lethal voltage is present on the primary. Install the heavy transformer with complete touch protection on a chassis capable of supporting its mass.

Questions about selection and use

Which 100 W output transformer suits Yorkville or Traynor reference 98694 or A1301?

Hammond 1750R is intended for these documented references and provides 2 kΩ plate-to-plate, 4/8/16 Ω taps, paper winding and a 100 W rating.

Which push-pull output transformer provides 2 kΩ plate-to-plate for a high-current parallel output stage?

Hammond 1750R is a suitable starting point for a correctly designed parallel push-pull stage requiring 2 kΩ plate-to-plate and a total loudspeaker load of 4, 8 or 16 Ω.

Can the Hammond 1750R be used with four EL34, 6CA7 or 6550 valves?

Yes, the Hammond 1750R can be used with four correctly operated output valves when the 2 kΩ load, supply voltages, quiescent currents, driver capability and 100 W transformer class suit the circuit.

Is the Hammond 1750R suitable for a service replacement?

Yes, the Hammond 1750R is suitable for service when reference 98694 or A1301, mounting, primary load and loudspeaker connections match and the secondary lead colours are verified on the delivered part.