Since then, I measured the output impedance of the Signstek DAC - took multiple measurements at different output levels. It is: 3.74 - 4.43 ohms, ~4.2 average. Not too bad... Also, the headphones are working great!

Thanks for the responses! >>The DACs with the MPCM2704 DAC chip, might have a headphone jack with a high output impedance This might be a true statement - appears that the same circuit is shared between the RCA and line-out... the DAC chip's reference design calls for multiple resisters in...

Hello! I'm hoping someone can help me with my question. I have a USB powered DAC with a built-in amplifier - model Signstek HIFI USB. This DAC has a PCM2704 chip (great sound BTW!) and according to its datasheet, the output power is 12mW with 32ohm load - also 1.8Vpp with 10k load. I'm assuming...