The only diff in routing is the signal passing through an OPA1656 and some extra coupling caps before going to the volume pot. Aside from that, identical path. MA12070 chip only accepts differential input so the OPA1656 makes an extra 'signal.' It's a good opamp. Most opamps are audibly transparent in any setup outside of a complete isolation environment so I wouldn't fret. MA12070 also only accepts 1.7Vpp input anyway so full SE is pretty close to saturation.
My mods to remove the relays / SE from input chain since it is always active and goes via relays. You can ignore everything circled in red.
Both potentiometers in my units showed up to a 10% imbalance between channels at some points so buyer be warned. Both units at max volume showed ~300-Ohm discrepancy between channels (it;s a 5k pot) so.... yeah. No idea if audible, but seems like a poor showing.
