I’ll try to summarize the posts and threads on this subject:
The DS has a higher noise floor that most PCM based DACs. That higher noise floor is inherent in single bit DSD DACs. E.g. check the review of the well received Playback Designs MPS-5 (https://www.stereophile.com/content/playback-designs-mps-5-sacdcd-player-measurements) One of the trade offs is that single bit DACs are also inherently linear and getting great linearity in PCM is costly. A ideal PCM DAC will have the same step size between all possible outputs (e.g. 65536 identically spaced steps for a 16 bit DAC…) but this can only be done with exacting components or by using randomness to average out the imperfections in the components that are not quite so perfect.
If the DSD based DAC’s output level is matched to the rest of your system, tho you might hear a hiss with your ears to the speaker, you almost certainly won’t at your listening position at any reasonable listening level. To help match the DAC’s output level to your system better the DS DACs have an optional 20dB analog attenuator. That attenuator will lower the output level, but it will also lower the noise by 20dB. It’s intended to be used if the majority of your listening is with the DS’s volume at 60 or below. Some systems seem to fall in the crack where the noise is too high when the attenuator isn’t used and the music is too low when the attenuator is used. Some of the people in this boat have chosen one of 1) if they were using a single ended connection using the balanced output to get 6dB more gain (see below) 2) use 10dB inline attenuators in their analog interconnects out of the DAC, 3) use a good audio transformer to change the levels 4) use a preamp, 5) if they have a DS Jr they get a DS Sr. (see below)
For option 1: Some systems have a balanced connection on the amp/preamp and can use the balanced connection directly. Some users buy a balanced to unbalanced converter: that can be as simple as a good audio transformer. A few systems have a preamp or amp with an isolated input (an input which isn’t connected to the ground) and can use the balanced connection directly or they can use a XLR to RCA adapter which is directly wired to put the balanced connection across the RCA (DON’T do this if your amp or preamp doesn’t have an isolated input, few do.)
The DS Sr has a 6dB quieter analog noise floor than the DS Jr - it achieves that by having four copies per channel of the digital switch and analog filtering which join at the output transformer. The DS Jr only has one copy of this circuitry - that’s one reason for the price difference between a DS Jr and a DS sr.
On the other hand the digital noise in the output of all of the releases before Redcloud was too colored. The ear is very insensitive to while noise, but noise with any sort of character (a slight pitch, quiet whistles, changing tone, etc.) is much more noticeable and intrusive. Redcloud addresses this directly and sounds noticeably quieter.