CAL Sigma tube DAC question....

Contemplating adding a tube DAC to my existing player...are there any significant sonic benefits to this?...I am not made of money, so any honest feedback would be appreciated...also,if there is a better,cheaper all means...let me know..thanks...
I got rid of my CAL Alpha for an Audio Alchemy 3.0 and love it. It was less hassel, very clean and no tubes. The Alpha constantly searched for input if I was using a different source than digital. Also, getting up off my butt to chose toslink/coax or ? defeated the purpose of relaxing to music. All CAL d/a's are nice but usually come with garbage chinese or russian tubes. For around $250, you can't beat it.
I've had a Sigma since it came out and have never had any

I have done a lot of mods to it:power supply,
caps and resistors in the signal path,bypassed
the toslink/coax switch, upgraded the 12ax7 and
other active parts.

I tried other DACs, DVD-A and CD/SACD players, and my Delta/Sigma combo still sounds great on redbook CDs.
I don't know what kind of cd player you have. I have briefly owned a sigma. It was very detailed and dynamic. However, it was not smoother or richer sound than the dac I already had, a Micromega Duo BS2. If you're looking for something to smooth out or warm up a clinical sounding cd player, I do not think a sigma is the answer. Suggest you try some rich sounding interconnects, such as MIT or Harmonic Technology before adding a dac.