1760W Hammond 100W Übertrager Twin Reverb Dual Showman Repl.

Hammond 1760W – 100 W output transformer for Twin Reverb and Dual Showman

The Hammond 1760W is a paper-wound, centre-tapped push-pull output transformer for high-powered valve guitar amplifiers. It provides a 2 kΩ plate-to-plate load, a 100 W rating and secondary outputs for 4, 8 and 16 Ω.

Hammond lists the 1760W for compatible Twin Reverb, Twin Reverb 100, Showman and Dual Showman circuits. Fender references 125A29A, 022889 and 022897 are listed for Twin Reverb applications, while 022689, 022899 and 037612 are additionally associated with parts of the Showman family.

Suitable applications

• Repair of compatible Twin Reverb and Twin Reverb 100 amplifiers
• Showman, Showman Reverb, Dual Showman and Dual Showman Reverb circuits
• Push-pull output stages requiring a nominal 2 kΩ plate-to-plate load
• 100 W valve amplifiers requiring 4, 8 or 16 Ω speaker outputs
• Replacement of a Hammond 1750W when additional 8 and 16 Ω taps are required

Technical data

Product type

Push-pull output transformer for valve guitar amplifiers

Manufacturer applications

Twin Reverb, Twin Reverb 100, Showman, Showman Reverb, Dual Showman and Dual Showman Reverb

Fender references for Twin Reverb

125A29A, 022889 and 022897

Additional Showman references

022689, 022899 and 037612, depending on the exact amplifier family

Primary impedance

2 kΩ plate-to-plate, centre-tapped

Secondary impedances

4, 8 and 16 Ω

Transformer power rating

100 W

Winding construction

Paper wound

Frequency response

70 Hz to 15 kHz, 0/-1 dB referenced to 1 kHz

Manufacturer distortion figure

Less than 1% at 70 Hz under the test conditions used in the Hammond data sheet

Primary inductance

4.55 H typical at 1 kHz, 1 V with the secondary open

Leakage inductance

1.280 mH typical at 1 kHz, 1 V with the secondary shorted

Primary DC resistance

13.24 Ω brown–red and 14.44 Ω red–blue, typical

Secondary DC resistance

0.110 Ω black–white, 0.175 Ω black–green and 0.279 Ω black–yellow, typical

Dielectric strength

2,000 V RMS

Temperature range

-40 to +105 °C

Construction

Open-frame chassis mounting

Flying leads

Primary and secondary leads at least 9 in or approximately 229 mm long

Dimensions

Approx. 103.2 × 88.0 × 88.9 mm according to drawing dimensions A × B × C

Mounting-related dimensions

D approx. 88.9 mm, E approx. 57.2 mm and F approx. 70.9 mm; slots approx. 4.75 × 7.62 mm

Shipping weight

Approx. 1.81 kg according to Hammond

Connections

Primary winding

Brown and blue to the output-stage plates, red centre tap to the high-voltage supply

4 Ω output

Black common and white 4 Ω tap

8 Ω output

Black common and green 8 Ω tap

16 Ω output

Black common and yellow 16 Ω tap

Comparison with the 1750W and 1750WA

Hammond 1760W

2 kΩ plate-to-plate, 100 W, paper wound, with 4, 8 and 16 Ω outputs

Hammond 1750W

2 kΩ plate-to-plate, 100 W, with a single 4 Ω output

Hammond 1750WA

2 kΩ plate-to-plate, 100 W, with 2, 4 and 8 Ω outputs

Selection and installation notes

Connect the speaker to the tap carrying the same nominal impedance. A mismatch changes the primary load reflected to the output valves and therefore affects current, power and distortion behaviour.

The 100 W figure is the transformer's rating and does not guarantee the amplifier power measured at the speaker. The primary load, supply voltages, valve complement, bias conditions and operating class must all suit the circuit.

In amplifiers using global negative feedback, check the selected secondary tap and transformer phase. Reversed primary connections can turn negative feedback into positive feedback. Insulate every unused secondary lead separately.

Lethal voltages may be present on the primary wiring. Installation and testing require suitable expertise, a disconnected mains supply, safely discharged filter capacitors, touch protection and adequate insulation clearances.

Questions about selection and use

Which output transformer suits a 100 W Twin Reverb output stage?

Hammond 1760W is the documented multi-tap version for compatible Twin Reverb and Twin Reverb 100 circuits. It provides a 2 kΩ plate-to-plate load, a 100 W rating and 4, 8 and 16 Ω outputs; amplifier revision, mounting and feedback must match.

Which output transformer provides 4, 8 and 16 ohm outputs for a Dual Showman?

Hammond 1760W combines a 2 kΩ centre-tapped primary with a 100 W rating and three speaker outputs. Hammond lists it for compatible Showman, Dual Showman and Showman Reverb applications.

Can the Hammond 1760W replace the Hammond 1750W?

Yes, the Hammond 1760W can replace the 1750W in compatible circuits when the primary load, rating, mounting and phase match. The 1760W adds 8 and 16 Ω outputs to the 4 Ω connection.

Is the Hammond 1760W intended for Fender references 125A29A and 022889?

Yes, Hammond lists the 1760W for 125A29A and 022889 and, depending on the amplifier family, also for 022897, 022689, 022899 and 037612. The exact amplifier revision must still be checked.