Am I asking too much?

You'll feel for me more after you hear this one.  So, I'm trying to get my tube amp out of the rack to check out the tubes, disconnected the speakers (or so I thought) and dragged the amp to another rack when my audio physic bookshelves toppled and I got the second ding in a month.  This one to the still pristine speaker which I've had for a month and a half.  Aaaaagh!  I'm beside myself for the second time in a month.  $3000 speakers all banged up.  Will deal with the ****ing tubes tomorrow.  I do think the tubes may be the culprit.  To answer some of the other posts, at low levels I don't hear the hiss, but I know it's there and don't know exactly when it creeps in.  I'm trying to demo a Symposium isolation platform and my heart isn't into it if I don't have a good base level from which to compare.  
Aaaagh!

Consider the ding a blessing!  Now you will not need to worry about dinging your brand new speakers. Rub some shoe polish in it and forget about it.

Also if you cannot hear it when listening to music...

Udog, it sounds like it's a noise floor issue. Your DC likely isn't quiet enough so you are hearing some noise that it isn't filtering out. You have a few options, you can, if you know how to work on audio equipment without killing yourself, add smaller filter caps to bypass your current capacitors. .1 and .01uf may help. One common problem is the heater voltage, it's usually AC. If your amp is push-pull, than only the driver tubes on the input would need to be converted to DC, but AC uses less current as it's only putting out full voltage/current at the peaks of the sine waves, so while you can buy AC to DC converters on eBay, your transformer almost certainly can not sustain the higher current DC supplies, so you would have to buy another transformer just to run the DC which I believe uses 1.8 times the current AC uses, but just double it to be safe. I think 6SN7s use about 1.3 to 1.5 amps AC, so you would want a transformer that can supply about 3 amps per tube. Often that will cure your problem. Otherwise if it's really driving you crazy, a completely new power supply may be needed. Another option might be a new amp. Don Sachs makes an amp that puts out DC that is so quiet that the AC noise is in the micro volts, you can't hear that even with the most efficient speakers there are.

The small filter caps won't help. The heater voltage hypothesis is not relevant in this case. The user is hearing quiescent current flowing through the electronics. This is normal.

So you hear a hiss at volumes you don't listen to and you're  worried about it? HaHa, Ok!