LL1517 is an audio output transformer for balanced or unbalanced drive. The transformer is built from two three section coils, with primaries and secondaries separated by electrostatic shields, and a audio C-core of our own production. The transformer is housed in a mu-metal housing. The LL1517 has sufficient low copper resistance to meet broadcast specifications in a conventional drive configuration, but is (as all output transformers) ideally used with mixed feedback drive circuits. (See separate paper for mixed feedback design principles).
Turns ratio: 1 + 1 : 1 + 1
Technical Details:
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Dims (Length x Width x Height above PCB (mm)): 47 x 34 x 18
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Spacing between pins: 5.08 mm (0.2")
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Spacing between rows of pins: 35.56 mm (1.4")
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Weight: 105 g
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Core: Audio C-core
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Housing: Mu-metal
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Rec. PCB hole diameter: 1.5 mm
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Static resistance of each primary: 9.2 ohms ?
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Static resistance of each secondary: 9.5 ohms??
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Leakage inductance of secondaries (sec. in series): 0.3 mH
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No-load impedance: Typically > 600 ohms @ 50
Hz, +20 dBU
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Optimum source impedance: Minus 18 ohms?
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Balance of output (according to IRT, source < 10 ohms , Load 600 ohms?? ? > 60 dB
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Maximum output level before saturation (sec. in series, load 600 ohms ) + 24 dBU @ 30 Hz
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Distortion (achieved with mixed feedback drive circuit, load 600 ohms ) < 0.03 % @ 20 dBU, 30Hz
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Frequency response (source 10 ohms ,load 600 ohms ): 10 Hz -- 80 kHz +/- 0.3 dB
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Loss across transformer (at midband with 600 ? load): 0.3 dB
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Isolation between primary and secondary windings / between windings and core: 4 kV / 2 kV
