Benchmark DAC-1 vs DAC-1 HDR

The Benchmark DAC-1 has recieved stellar comments on this site. Their HDR offers additional benefits and appears to have no drawbacks in comparison (other than price). I know they switched op amps between the DAC-1 and the DAC-1 PRE and DAC-1 HDR. Has anyone found a downside between the models as one goes up the line ?
I've owned a dac 1 USB for a couple of years, and just took delivery of an HDR. Although I haven't compared them side to side, I have had them in the same system and have not noticed a difference between the two. On the other hand, the two systems couldn't be more divergent. Tannoy with vintage tubes vs Soundlab with high power solid state. Have you tried different power cords/conditioners, as they are sensitive to them?
If you ever find the DAC-1 sounded a little white or edgy and not as smooth as you expected, make sure you put a pair of snap-on ferrite cores on each end of all digital cables except toslink, as well as on the power cord; it is particularly important if you use USB.

Those snap-on ferrite cores are cheap and you will be surprised what a difference they make.
Is anyone running a Benchmark DAC-1 output to a preamp rather than directly to an amp (i.e CDP to DAC-1 to Preamp to amp)? Even better, is anyone running it to a Mcintosh solid state preamp? If so, what attenuator setting did you use ? Additionally, what was the effect of inserting the DAC-1?

You can do that - but you will likely need the 20 db attenuation - you can verify that you are not overdriving teh pre by using the volume control on a loud loud CD track and see if you reduce distortion by reducing the volume.

You will lose the benefits of balanced XLR if you go to a preamp with only RCA (although the difference in most cases may not be audible but could be a significant factor on long runs).
I ran thr benchmarck dac1 directly into my amp, balanced, and was unimpressed. I think it sounds awesome into my preamp. Into the amp directly, it had no emotion, body, soul. I didn't bob my head, as I do through the preamp. Just my experience with these old ears.
I also tried running it directly into my amp. It sounded better when my preamp was in the chain. More bloom an depth to the soundstage.
I run my benchmark to a Mcintosh C220 Tube....Tried it without directly into Tube mcintosh 2102.I like the preamp in the chain.I like the bloom and roundness that it provided.