What preamp tubes do you have in your Deuce? white noise or hiss can be common with JJ or Mesa JJ tubes after a few months of use.
It may just be a preamp tube causing you the grief. That being said, I have had similar issues with Mark V and Mark IV, as well as RA100. Not yet with the Roadster. Tube rolling is one way to fix or find the cause of the hiss. Characteristics of most current production 12ax7 tubes will change with use, some will get the onset of white noise (JJ and Chinese), some will develop parasitic hum (prone with Russian tubes TS, EH, Mullard, etc....), and all of the above may get popcorn noises. Note that Rectifier series amps have two Cathode Follower circuits (tone stack and Effects loop, do not use any Russian tubes in those positions, only JJ or Chinese).
If unrelated to preamp tubes, it may associated with bypass cap on a gain stage, or carbon composition resistor (which tend to be noisy in audio circuits). Tubes may test okay since most tube testers do not listen to the tubes, they only check gain compared to applied voltages. I would definitely tube roll your Deuce, a tube may make hiss in one position but not in another. Keep in mind that with some channels or gain shift, there is also a voltage change so that may make a difference. Considering the Mark V, I was getting parasitic hum with CH1 clean, and CH3 but totally quiet in CH2. The Mark V shifts voltage levels to some tubes which is higher for CH1 and CH3 and lower for CH2. Now it is very quiet on all three channels with no guitar input, took me a while to find tubes that remained quiet with all modes and channels. When it comes to tube amps, there will be some noise and will not be dead quiet with very high gain settings but it is possible to find tubes that sound great and yet remain stable and quiet without any signal applied.
The Mark V is an incredible amp. I have had mine for 2 years now and it still has the WOW factor. The Roadster is still new to me and is getting more attention at the moment, when I power up the Mark V and get lost in a host of satisfying tones I do not want to play though anything else. Perfect amp for Humbucker or single coil guitars. The only thing I have not tried through it is a Semi or hollow body guitar. What is even more exciting is the response to different preamp tubes if you so desire. I actually prefer the Mesa Stock preamp tubes in this amp over anything else. In all honesty, I love the Mark V, Roadster and RA100 equally. if there was an amp with specific character, gain structure and tone to be used as a bench mark to compare all others too, I would consider the Mark V to be it. Definitely something to try out at a local Mesa dealer. I am not trying to plug the Mark V, I am just offering my opinion.