Firstly changing/swapping/rolling Op amps can actually make the circuitry worse than using the stock Op amps.
Now that I have that out of the way.
The JDS Labs Atom DAC+ measures and tests very well here @ ASR. It uses SMD type Op amps that would require a soldering iron, solder, some liquid flux, isopropyl alcohol and tools for disassembly and reassembly. It is more work than just unplugging and plugging in a Op amp to a receptacle/socket. If you are going to roll Op amps then you could at least use solder and learn to solder while you are doing it.
This is a review and detailed measurements of the JDS Labs Atom DAC+ desktop USB DAC. It was sent to me by the company and is an early production sample. The product was just announced at a retail cost of US $109. I accepted the sample in the interest of getting this information to you early...
www.audiosciencereview.com
Atom DAC+ is built to pair with the enormously popular JDS Labs Atom Amp, now with even higher performance, both USB and TOSLINK inputs, and our latest upgradeable XMOS based firmware with UAC2 support and UAC1 fallback*. Atom DAC+'s subtle light ring glows when in use, automatically powers down...
jdslabs.com