I was tinkering in LTSpice with adding a Jensen line input transformer to the B1K preamp. As I tried to educate myself on audio transformers (largely from materials on Jensen's site), I realized an idealized transformer in LT Spice didn't really seem to represent an actual transformer. (shocker )

I'm interested in a 1:1 Jensen line input transformer (JT-11P-1HPC). I tried contacting Jensen to ask if they had simulation models available - no response. So here is my attempt to model this particular transformer in LTSpice.

I used the "Test Circuit 1" from the transformer's datasheet. I used these steps to create the model:

The frequency response and voltage gain of resulting model seems to conform to the datasheet with one exception. The deviation from linear phase at the high end of the audio frequency range is accumulating faster than the datasheet.

I've also noted that the imputed parallel resistance forms a voltage divider to arrive at the voltage gain stated on the datasheet. As a result, the gain of the circuit seems to be highly dependent on source resistance.

Any thoughts on this approach? Does it have any validity, or is this a misguided effort?

I'm interested in a 1:1 Jensen line input transformer (JT-11P-1HPC). I tried contacting Jensen to ask if they had simulation models available - no response. So here is my attempt to model this particular transformer in LTSpice.

I used the "Test Circuit 1" from the transformer's datasheet. I used these steps to create the model:

- Inductance imputed from datasheet primary series resistance and low frequency corner (0.25Hz).
- Leakage imputed from datasheet secondary series resistance and high frequency corner (80kHz).
- Parallel resistance imputed from datasheet source resistance and voltage gain (-3dB).

The frequency response and voltage gain of resulting model seems to conform to the datasheet with one exception. The deviation from linear phase at the high end of the audio frequency range is accumulating faster than the datasheet.

I've also noted that the imputed parallel resistance forms a voltage divider to arrive at the voltage gain stated on the datasheet. As a result, the gain of the circuit seems to be highly dependent on source resistance.

Any thoughts on this approach? Does it have any validity, or is this a misguided effort?