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60 watt tube amp needs a 5k primary and 8 ohm secondary transformer. I have wound voltage transformers on my lathe many times. Audio transformer is no different. Online impedance transformer calculator says, 5k to 8 ohms in 25:1 ratio. Online info says, audio transformer should be 60w x 5 = 300 watts over sized 5 times so peak pulses are not cut off.

Online says, Don't try to calculate. Inductance will depend on many parameters. Some of these parameters are easy to determine (cross-section, magnetic path length), but others not so (mu, stacking factor, effective gap). Furthermore, inductance depends much on frequency and AC voltage amplitude. So, wind a test winding and measure it under your specific conditions.

Suggestions are to wind 500 turns on the EI core, assemble transformer then test it. If 500 turns measures 7 Henrys then mu formula will show that to be 4690 impedance. I need need the mu formula. I need help determining how many turns are on the 5K primary. Suggestions are to change the 500 turn primary several times and test it each time then draw a graph to determine how many turns are needed to = 5K impedance, then built it and test it to see if it is 5K..

Suggestions?

Online says, Don't try to calculate. Inductance will depend on many parameters. Some of these parameters are easy to determine (cross-section, magnetic path length), but others not so (mu, stacking factor, effective gap). Furthermore, inductance depends much on frequency and AC voltage amplitude. So, wind a test winding and measure it under your specific conditions.

Suggestions are to wind 500 turns on the EI core, assemble transformer then test it. If 500 turns measures 7 Henrys then mu formula will show that to be 4690 impedance. I need need the mu formula. I need help determining how many turns are on the 5K primary. Suggestions are to change the 500 turn primary several times and test it each time then draw a graph to determine how many turns are needed to = 5K impedance, then built it and test it to see if it is 5K..

Suggestions?

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