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Can someone please show me how to calculate the current, voltage, and impedance that the LineLevelInput will receive?

In the schematic below:

  • The left-side of the schematic represents the source of the signal, and the right-side represents the destination.
  • SpeakerOut represents the speaker output of a small tube amp.
  • R1 represents a dummy load resistor for the small tube amp.
  • The transformer has a 1:8.66 turns ratio and a 1:75 impedance ratio.
  • LineLevelInput represents the line-level input of a larger power amp with an input impedance of 10kΩ.

I really appreciate your help. I am trying to build a little DIY impedance-matching box. Please don't worry about overloading the input -- I am just trying to understand how to do the current, voltage, and impedance calculations at this point. I read about Ohm's Law and Kirchoff's Circuit Laws so I have the puzzle pieces in my hands but I don't know how to put them together.

Many, many thanks for your very kind help!!

Sincerely, Nickel

Schematic

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  • \$\begingroup\$ What are you trying to do? An audio line-level input is voltage only, and needs very little power indeed. Impedance matching is not required. \$\endgroup\$
    – Tim Williams
    Commented Jul 22, 2023 at 16:46
  • \$\begingroup\$ I think you are looking for ohm's law. \$\endgroup\$
    – Julien
    Commented Jul 22, 2023 at 16:47
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    \$\begingroup\$ There is not enough information to calculate anything. Also, wattage consumed by a line level input is usually never needes for anything. For what purpose you need it? Also it makes little sense to step up the voltage. If the amplifier does put put say 1 Vrms which is 0.125W, the transformer steps up that voltage to 8.66 Vrms which is extremely high for a line level and may damage the line input. Also, line inputs don't need impedance matching so why do you want impedance conversion? \$\endgroup\$
    – Justme
    Commented Jul 22, 2023 at 16:59
  • \$\begingroup\$ Apologies to everyone. I am so ignorant it is hard for me to even ask a meaningful question. \$\endgroup\$
    – Nickel1234
    Commented Jul 23, 2023 at 3:43
  • \$\begingroup\$ The underlying problem is this -- I have a very weak signal coming from the speaker output of a small tube amp that I want to convert to a line-level signal and feed into the line-level input of a larger power amp. When I use a store-bought converter box, the power-amp's input receives a very weak signal. I reason that the converter box is, by design, converting only a small fraction of the power from the speaker out to line level. \$\endgroup\$
    – Nickel1234
    Commented Jul 23, 2023 at 3:48

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