Twindac+ and Django (BD-Design)

by unknown, Wednesday, September 20, 2006, 14:51 (6434 days ago) @ dr.cube

Correct, a transformer caNot amplify power, but we can increase the voltage due to the turning ratio of a transformer. There is little current draw from the input of the amp. So, the drive of this transformer is sufficient for the amp. If it would not be, you would notice an early roll off in the low end of frequencies.

As you mentioned, a transformer merely transforms a load impedance on its secondary. The turn ratio or the voltage ratio between primary and secondary governs the transformed and reflected load impedance.

By having a transformer as suggested, you caNot achieve a stable impedance at the DAC chip output, as the impedance changes with different turn ratios.

The output transformer is optimal loaded for the DAC. This is critical. The reflected impedance is low. By adding a transformer attentuator, with a high loading impedance (amp), the reflected impedance of the transformer attentuator can be neglected. It does not change the impedance that the DAC sees practically.

In addition, as you mentioned as well, a transformer is always a compromise. Designing, using the right materials, winding techniques etc. is not that simple at all. That is also the reason that a quality transformer costs quite a lot of money.

Mirko

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