1750PA Hammond PP Übertrager 18W Combo Marshall 8,4k 4/8/16
€52.30
Delivery time: ca. 1 - 5 days
8.4 kO plate-to-plate with 4, 8 and 16 O outputs for two EL84 valves
Paper winding suits 1974X-style combos and compatible new builds in use
18 W, 70.3 H, 70 Hz15 kHz, 1.81 kg and 1.5 kV isolation in operation
Hammond 1750PA – paper-wound 18 W output transformer for Marshall combos
The Hammond 1750PA is a paper-wound push-pull output transformer providing 8.4 kΩ plate-to-plate and secondary taps for 4, 8 and 16 Ω. Hammond documents it for classic Marshall 18 Watt Combo applications.
A typical output stage uses two EL84 valves in total. The three loudspeaker taps support correct matching of several cabinets without changing the nominal primary load.
Suitable applications
- Marshall 18 Watt Combos with a matching circuit and mechanical layout
- 1974X-style two-EL84 push-pull output stages
- New amplifiers requiring approximately 8.4 kΩ
- Total loudspeaker loads of 4, 8 or 16 Ω
- Guitar amplifiers in the 18 W transformer class
- Service and restoration projects with verified feedback phase
Technical data
- Product type
- Push-pull guitar-amplifier output transformer
- Model
- Hammond 1750PA
- Documented amplifier family
- Marshall 18 Watt Combo
- Primary impedance
- 8.4 kΩ plate-to-plate with centre tap
- Secondary impedances
- 4, 8 and 16 Ω
- Transformer power rating
- 18 W
- Amplifier topology
- Push pull
- Typical output-valve complement
- Two EL84 valves in total at a suitable operating point
- Winding type
- Paper winding
- Primary inductance
- Approx. 70.30 H at 1 kHz, 1 V and open secondary
- Brown-to-red primary DC resistance
- Approx. 298.94 Ω
- Red-to-blue primary DC resistance
- Approx. 335.45 Ω
- Total brown-to-blue primary DC resistance
- Approximately 634.39 Ω
- Black-to-orange secondary DC resistance
- Approx. 1.40 Ω across the complete 16 Ω winding
- Primary leakage inductance
- Approx. 66.18 mH at 1 kHz, 1 V and short-circuited secondary
- Frequency response
- 70 Hz to 15 kHz, 0/-2 dB referenced to 1 kHz
- Distortion
- Less than 1% at 70 Hz under the documented test conditions
- Dielectric test
- 1,500 V RMS
- Temperature range
- -40 to +105 °C
- Lead length
- At least approximately 178 mm or 7 inches
- Dimensions
- Approx. 101.6 × 66.7 × 51.8 mm
- Mounting centres
- Approx. 90.5 mm
- Mounting-hole diameter
- Approx. 4.75 mm
- Hammond shipping weight
- Approx. 1.81 kg
Lead connections
- Brown
- First primary connection to one EL84 plate
- Red
- Primary centre tap to B+
- Blue
- Second primary connection to the opposite EL84 plate
- Black
- Secondary common or loudspeaker ground
- Yellow
- 4 Ω loudspeaker tap
- Green
- 8 Ω loudspeaker tap
- Orange
- 16 Ω loudspeaker tap
Selecting the loudspeaker impedance
The selected secondary tap must match the complete impedance of all connected loudspeakers. Insulate each unused tap separately.
A 4, 8 or 16 Ω cabinet produces the nominal 8.4 kΩ primary load only on its corresponding tap. An intentional mismatch requires a new assessment of valve current, dissipation and expected output.
Comparison with the Hammond 1750E
The Hammond 1750PA provides 8.4 kΩ, an 18 W rating, paper winding and 4/8/16 Ω taps. The Hammond 1750E provides 8.5 kΩ, a 15 W rating, bobbin winding and a fixed 8 Ω output for different Fender-oriented applications.
The similar primary impedances alone do not establish mechanical or electrical interchangeability.
Safety notes
Lethal plate and signal voltages are present on the primary. Install the transformer with complete touch protection and verify winding phase where amplifier feedback is used.
Questions about selection and use
Which output transformer suits a Marshall 18 Watt Combo or a 1974X-style output stage?
Hammond 1750PA is documented for Marshall 18 Watt Combo applications and provides 8.4 kΩ plate-to-plate, 4/8/16 Ω taps, paper winding and an 18 W rating.
Which paper-wound output transformer suits two EL84 valves with 8.4 kΩ and several speaker impedances?
Hammond 1750PA is a suitable starting point for a correctly designed two-EL84 push-pull stage requiring 8.4 kΩ plate-to-plate and a total load of 4, 8 or 16 Ω.
Can the Hammond 1750PA be configured for 4, 8 or 16 Ω?
Yes, the Hammond 1750PA has separate secondary taps for 4, 8 and 16 Ω. Use the tap corresponding to the actual total loudspeaker impedance.
Is the Hammond 1750PA suitable for a newly built 18 W EL84 amplifier?
Yes, the Hammond 1750PA can be used in a new amplifier when the 8.4 kΩ load, 18 W rating, loudspeaker impedance, plate and screen voltage and quiescent currents suit the selected EL84 circuit.
Note: All brand names mentioned, such as Marshall, Fender, etc., are registered trademarks of their respective owners and are used here for descriptive and compatibility purposes only.
Hammond Electronics B.V. Willemswerf Boompjes 40
NL-3011 XB Rotterdam
Email: info@hammfg.com
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Source: IHK Mittelfranken
Tariff Number: 85043129000
Country of Origin: DE
Weight: 1,82 kg