The speaker sensitivity hypothesis is just my guess. Learning that it is well within the tube rush generated by some tube amps is helpful as a reference.
The sensitivity on my speakers is 87db.
There’s no hiss with my DAC with a tube output stage when it’s connected directly to my amp.
Which is, as others have asked, what exactly? And this relates to the specific discussion of the DS how? 
On topic, I assume you understand the hypothesis of hiss with a combination of amp sensitivity, gain structure and speaker sensitivity is specific to why some hear hiss with the DS and some do not. Yes?
There is a 20dB attenuation option for those with more sensitive systems that often helps.
Excellent suggestion. I should have thought of this.
Elk said ... the hypothesis of hiss with a combination of amp sensitivity, gain structure and speaker sensitivity is specific to why some hear hiss with the DS and some do not.To each hiss own
Ted Smith said There is a 20dB attenuation option for those with more sensitive systems that often helps.Only problem is with the DS directly connected to an amp with the low level setting, 140mv unbalanced and 280mv balanced isn't going to drive any amps I know of and the hiss will still be there and get modulated with the rest of the signal.
The DS with attenuator still drives my amps way too loud for nighttime listening. The attenuator attenuates the hiss as well as the signal and the hiss doesn’t get modulated by the signal.
Ted Smith said The DS with attenuator still drives my amps way too loud for nighttime listening. The attenuator attenuates the hiss as well as the signal and the hiss doesn't get modulated by the signal.Never said the hiss gets modulated by the signal. The hiss attenuated or not will always be there and get amplified along with the rest of the signal.
Ted Smith said The DS with attenuator still drives my amps way too loud for nighttime listening.+1
For that matter, the DS with attenuator drives my amps loud enough for daytime listening as well, with rare exception.
dan said I don't think there anything wrong with my DS, the hiss can't be heard at the listening position.Exactly.
So what DAC did you concluded works better in your system with which you are replacing the DS?
wim said To each hiss own
Well done.
dan said Never said the hiss gets modulated by the signal.Nor did Ted indicate you did. :) He is adding additional information to the discussion.
The hiss attenuated or not will always be there and get amplified along with the rest of the signal.I would be extremely surprised if the hiss is amplified with the signal. I expect the hiss remains at precisely the same level of audibility, regardless of volume setting, including at zero.
That is correct. The hiss is 120dB down (or more, Ted will have to interject). The his never modulates or changes with signal.
[This post and succeeding posts moved from the Stereophile review thread to here]
Hi Dan -
You still haven’t told us the DAC you’ve found that bested the DS. Or is there one?
In the meantime, you keep hanging around here, complaining and criticizing other forum members.
IMO, time to put up or…
Bill
PS (no pun intended) I hope this isn’t deleted!
DS mute function thread post #15.
Then why did you bring it up again?
[Last of moved posts]
I think it’s this one:
Aesthetix Romulus / Pandora