Do all tube preamps leak DC?

Hi Paul,  3 years ago Ralph Atmas-phere convinced me to open up my tube/solid state hybrid digital player that I run directly to my modified krell 700cx amplifier to prove that I had no DC leakage,  as a matter of fact, I have two coupling capacitors behind each tube,  krell once accused my player was the fault of on going problems with my amplifier,  it took Dan D’Agostino himself to tell me by speed dial on my phone to share with me what was actually wrong with my amplifier after modifications,  it was two heat sensors on the left side of the amplifier,  the amplifier has a total of six,  three on each side,  when I told krell how to fix the problem with the amplifier,  they wanted to know how I knew that,  of course I could not divulge who told me,  any way,  Ralph is a good friend of mine,  when it comes to this subject here of DC leakage,  I learned every thing I know on the subject from him,  I assure you Paul,  you can take what he has said as the gospel! 

Hi Keith, I believe you are correct about Ralph & would agree that he is very knowledgeable. It is nice to know that we have people like him to provide reliable info on most given subjects (questions) but you are also in the "A" Class, an asset to the audio community and a hell of a good guy to boot.

Paul,  have you taken the hood off the Audible illusions l1 preamplifier to visually check if you have coupling capacitors located next to the tubes?, and check the condition of the capacitors?, also,  I would ask Ralph here how to check if the specifications are up to par on the coupling capacitors even if they pass the visual inspection,  sometimes capacitors dry out,  or are just to old,  if all this passes,  I believe you have no worries of DC,  however,  if the capacitors fail any of the mentioned here,  I would replace before proceeding,  cheers. 

Keith yes, although this particular Audible Illusions L1 is factory refurbished, I removed the top cover after I received it to inspect the tubes. There are two large caps near the output and four smaller Panasonic caps next to those. According to the manual the four dip switches are there to turn off the four smaller Panasonic cap only leaving those two bigger caps remaining in the signal path. At this point I feel very confident based on what I have read here on this thread, that I don't need to be concerned about DC and would like to thank all those that participated!