As an op-amp fetishist (since reformed), there are no op-amps on the board. It's circuit is different. I'm sure an EE here will explain it better then I, but the last Topping with swappable op-amps was the DX7 Pro. It had slots for duals in the headphone and the pre-pro stages. Getting 2 Burson V6 Vivids required a messed up bit of legerdemain, I'd rather not do again. Getting 8 or even 16 into the DM7 case would be grounds for a long stay in rehab. If you spend anytime in ASR, opamps are universally discounted as adding anything to the sound chain other a certain smugness to your listening pleasure (I count myself as a graduate of that school of sin). Enjoy the DM7 for what it is, a piece of tech from 20 years in the future somehow bestowed on the present. Hook up 8 XLR's, play surround music, LOUD and enjoy the ride.