Hi Ralph,
See the following datasheet, and the note near the bottom of page 1 of the user manual for the PI2XX (the unit shown has balanced inputs and balanced outputs, but a similar model can be ordered with unbalanced inputs):
Datasheet: http://www.jensen-transformers.com/datashts/pi2xx.pdf
User Manual: http://www.jensen-transformers.com/datashts/pi2xx_usr_man.pdf
Note that the recommended load impedance range is 10K to infinity. And that the output impedance of the transformer at 1kHz, with a 600 ohm source impedance connected, is very high at 4.65K, of which 1.9K is dc resistance.
Given the very high output impedance, it would seem to make sense that cable capacitance should be kept very low, to avoid high frequency rolloff. That would apply whether the output is balanced or unbalanced.
Your comments appear to be applicable to output transformers, such as this one, which as explained in this application note will not perform as well in terms of cmrr as will an input transformer.
Best regards,
-- Al
See the following datasheet, and the note near the bottom of page 1 of the user manual for the PI2XX (the unit shown has balanced inputs and balanced outputs, but a similar model can be ordered with unbalanced inputs):
Datasheet: http://www.jensen-transformers.com/datashts/pi2xx.pdf
User Manual: http://www.jensen-transformers.com/datashts/pi2xx_usr_man.pdf
Note that the recommended load impedance range is 10K to infinity. And that the output impedance of the transformer at 1kHz, with a 600 ohm source impedance connected, is very high at 4.65K, of which 1.9K is dc resistance.
Given the very high output impedance, it would seem to make sense that cable capacitance should be kept very low, to avoid high frequency rolloff. That would apply whether the output is balanced or unbalanced.
Your comments appear to be applicable to output transformers, such as this one, which as explained in this application note will not perform as well in terms of cmrr as will an input transformer.
Best regards,
-- Al