They used a number of DAC's in their CD players and even the cheaper ones I think use 2 pairs or something like that with one pair in dual differential configuration I believe.
More complex is not always better. I can't comment on sound on any of the above but when one of Leema's players was measured it was below what is possible with todays technology. As it happens, in the subjective listening test it fared very well. It leads me to believe there was some deliberate engineering to make it sound the way it did, rightly or wrongly but it was not as accurate as others. Oddly enough, the same result in one of the mags for the Audiolab CD player. Seems that complexity does not equal good measurement which in turn does not equal bad sound but it seems removed of what is possible technically with these chips.
Leema's unique selling point for their digital sources/DAC's just happens to be the use of multiple DAC's. I really dont know if that technically adds anything that can't be achieved with a far simpler solution, especially as modern DAC boards have been quoted as being very good the way they come.
Other manufacturers use different topologies. They all have their own take but I like the look of Leemas more expensive products if that counts.
regards