There are several points you must keep in mind here.
- A DAC works best with an integrated amplifier or a preamplifier/amplifier combination, and, passive speakers.
- The 3.5mm output of a PC/Laptop is meant for headphones. What comes from this port is an analogue signal.
- In general, digital signals are carried through USB, Co-axial, Optical and HDMI ports. RCA ports are meant for and can only carry analogue signals.
- If you feed the analogue signal to a DAC, in the best-case scenario, the DAC will switch to being just a preamp. In the worst-case scenario, it will fiddle around with the signal and may make it worse.
- Most active speakers have internal DSP in which they fine-tune the audio signal to suit the speaker driver configuration. For example, Edifier boasts of enhanced bass irrespective of the driver size. What they do is to enhance the low frequencies and pump them to the 4” drivers on the 1850. This model also has a sub-out, which means low frequencies are expected to be amplified and played by an external sub-woofer. So there is active frequency separation inside the speakers.
If you insert a DAC between the non-digital source and the 1850, you will certainly hear a difference. Good or bad is doubtful and very subjective.
If you can get a digital out from your source feed that directly to the Edifier. That will be the best option.