Sony S7700, S7000, or ??? best low cost transport?

It depends very much on the DAC and its sensitivity to jitter. Many transports sound different because of the amount of jitter they produce and how well the DAC is able to correct for it.

The better your DAC handles jitter, less difference you’ll have between transports.

I have the Sony DVP-S7700 as my transport with a Bel Canto DAC-2. The Sony is well-built and sounded a slight bit better in base resolution than a few other transports I tried (on the coax output). But, it was not a BIG difference. The Benchmark Media DAC1 is also very jitter immune and the different transports I tried with it all sounded pretty much the same.

A dissenting opinion:
For the used prices the 7000 & 7700 are going for they're hard to beat as transports.

Sure, an expensive transport like a CEC or SCD-1 will better it, but when modded (total<$1K) the cheaper Sonys will generally provide more detail in a musically satisfying way than the most of the cheaper CD players and transports, IMHO.

My 7000 is stock and my 7700 is Modwright modified w/ bybees. I've used several other <$2,000 transports over the years, and still run a Micromega in one system (which is smoother, but more opaque, and which, BTW, replaced a Delta).

None of them, however, were overall better than the modded 7700.

I agree that the Thetas and EADs provide good competition though.

Reubent - you just didn't select the right modder. The Sonys make superb transports: 7000, 7700 and 9000es. I prefer the simplicity, low power usage and size of the 7700. Mods focused on the digital output electronics by an experienced digital design engineer make a world of difference. See these posts:

http://www.audiocircle.com/circles/viewtopic.php?t=1998
http://www.audiocircle.com/circles/viewtopic.php?t=3602

Can the S7700 play CDRs?