Don't be surprise if you change your mind after actually giving the Femto DAC a serious audition. To my ears, It does not sound 'anything' like "those middling op-amps". My brother in London, England just traded in his $11,000 dCS Debussy for a Femto DAC and claims that it delivers significantly superior performance. Don't knock it till you've tried it.
I wasn't claiming that the Femto DAC uses middling op-amps. I don't know what it uses. I haven't seen anything about the internals at all. All I know is that it uses the XMOS chip again, and the Sabre DAC as well. I'm sure the components have been upgraded significantly over the standard Calyx DAC, but I'd like to know a little more about what they actually did before dropping nearly $7K - especially when there's the Overdrive SE available for around the same price.