I recently contacted and have been in communication with a quality U.S. distributor for op amps and we were discussing the upgrade cost of the Maverick DAC upgrade. At only $30 for a total of four OPA627 op amps (2 mounted to each adapter), this would come to $7.50 per chip, and that doesn't include the adapters or the labor to mount them. Unless they have some extremely cheap wholesale source of this component, or are making a loss on this part, I question their authenticity. Even purchasing 500+ units on Mouser, the unit price is $17.75, which would come to $71 for four. I don't know how they could afford to sell this upgrade for $30! These are not BrownDog adapters either. I contacted Ryan at Maverick and asked if they can send me a copy of the packing slip from their vendor they purchased the OPA627 op amps from. I imagine my request will fall on deaf ears. Just be warned everyone. IMHO I would save your money and put towards a known USA supplier who certifies the chips he sells.