- Impedance analyzer – measure transformer impedance as a load with respect to frequency, ~20 Hz to 20 kHz or more.
- Oscilloscope / spectrum analyzer – monitor or measure input and output waveforms integrity, frequency response and etc.
- Function generator – generate waveforms to be send to the DUT (device under test)
- Audio Analyzer – distortion, frequency response, THD, IM, SNR and various other parameters.
- If your chassis is small, remember to orientate the transformer gap to face AWAY from the tube or sensitive circuit to prevent magnetic coupling. This applies to all the cores that have gaps, like EI core, C-core, double C-core, R-core and such.
- Function generator (or sound card that can output signals)-> DUT (amplifier)-> 8 Ohm load (or actual speaker) -> oscilloscope
- P = V-square / R
- 1W = square(2.83V) / 8 Ohm
- 3.5W = square(5.3V) / 8 Ohm
- 8W = square(8V) / 8 Ohm
- And so forth.
- Inductive impedance = 2 * pi * F * L
- Capacitive impedance = 1 / (2 * pi * F * C)
Just imagine how hard it is to match both to get 0 deg where frequency varies from 20Hz to 20kHz or more! The variation is just too huge!
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