I am looking for a smoothest sounding outboard DAC

Lot of good smooth sounding dacs mentioned above.. I too second John's choice of Audio Note,,, there are a lot of decent dacs like mentioned above. The Audio Notes are quite surprising, I even think their entry level tube output dacs are surprisingly smooth sounding and inexpensive,,, to me they blow away dacs like the 24/96 MSB Link Dac which is a surprisingly decent very inexpensive dac,,, Even the old Classe Dac-1 isn't a bad sounding smooth Dac. I like the Audio Note that John mentioned,, don't forget you also need a good cable and transport to complete the smooth sound.. One of those belt driven CEC's and a good Audio Note Dac (like the tube Audio Note)along with a good dig cable will be about as good as anything for CD. The CEC and Audio Note seem to mate well together and a favorite for many top end analog people who strive for the best. John gave you a very good choice along with the others. John may even sell the Audio Notes.

I also own the Audio Note 3.1 Balanced Dac, and it is superb, if your budget permits. Joe at JC Audio can set you up with any Audio Note stuff you need.

Re: the above post, in fact, I just ordered a Spectral SDR 3000 transport to mate with it (will be doing a shootout soon with some other transports- too bad I don't have a CEC to add in the mix!)

There's a Timbre TT1 Dac on here now for $645, which is a steal. An oldie but a goodie, and super smooth.

Wadia 27 would be excellent.

Kora Hermes tube dac. Dynamic, liquid, rich and very, very smooth. I owned Bel Canto Dac 2 before and the Hermes walked all over it. The best dac south of $4K I've ever heard.