Mark Levinson 36 dac or Theta Gen V Best?

Based entirely on readings, of used ones on Audiogon now $1-$2k, two Altmann Attractions optioned with Jisco jitter reduction, or perhaps an Audio Note 2.1. Check out the Positive Feedback review on Altmann vs. AN. For Altmann you will need a fast 12V battery like Optima Yellow or Red Top. If cost no object perhaps Empirical Audio.

I still have a balanced Gen Va DAC that I compare from time to time to my modded Sony. The Gen Va is a pretty good DAC with a high-quality analog section. However performance depends very much on the quality of transport. With either of these units you are taking your chances on service. Theta no longer supports the older models, and Levinson will probably charge more than it's worth to repair the 36.

Gen Va slightly surpasses the stock SCD-1's DAC section, but my modified Sony DAC section is far ahead. In the price range of a used Gen Va or ML 36, perhaps think about something like a battery-powered Altmann Attraction with dejitter option. Any good reclocking DAC will tend to be less sensitive to transport quality. If budget allows another $1K, probably at least worth auditioning a new Bryston BCD-1.

I don't know all the Pioneer stuff. But based on the Elite multiformat players that I've heard in showrooms, I think a good minimimalist 2ch DAC from a manufacturer other than the consumer giants, should get RBCD close to the level of SACD or DVD-A on the Pioneer. IMO the older ML stuff sounds sterile. The Gen Va is a better choice, but has a slightly synthetic mid/treble region by comparison to more recent top units.