Tube Pre-amp Noise problems HELP


Does anyone know or have the knowledge about static sound in a tube pre-amp? How this happens, why it happens what could be done to fix this problem.
This is my 5th tube pre-amp. First was a Conrad Johnson PV10A, the moment I switched the tubes, I heard a very very annouying static sound. I cleaned the tube pins and sprayed clean the tube sockets it helped a little but the problem existed. Audio Research LS7 had no issues. Then Conrad Johnson PV10B I had the same problems as the PV10A, I sent to conrad Johnson and got it upgraded and yet the problem existed. Then I tried a Sonic Frontiers SFL-2 SE again this static issue came after some time, this time I did not change the tubes. Now I have a Audio Experience A1 and the moment I switched the Original tubes I heard the annoying static sound, I switched back to original tubes but problem exists. They all have the same kind of hiss. Some call it tube stress, I dont know what it is. Even when I switch the tubes the hiss still continues, suddenly it goes away but eventually it returns. Can anyone help me on this?
128x128dseanm
Post removed 
Hello,

I now have a Monarchy NM24 DAC/Linestage which uses 4 6DJ8's. I changed out the stock Phillips and substituted some Amperex Bugle boys and have experienced hissing,dog whistles. I had a matched set of 8 and changed them 1 by 1.

I was able to eliminate the hissing but the D whistle persisted in one channel. I continued to substitute different tubes and it finally disapeared.

I must say low level noise can have many sources. Here are some things to check.

Remove all sources of RF emitting devices from your listening room. This includes portable phones,cell phones,remotes ect.

Check that all interconects are seperated from each other as best you can. Power cables should not be in close contact the interconnects or speaker cables.

If possible think about having direct circuts for your sound system. I have 4 20 amp Porter ports which are Hubbel 8300H hospital grade plugs. This cost me about 800 dollars for the wiring and 150 for the ports well worth it in my book.

Checking all these things and your issues are'nt resolved. I can only say it can be one big pain. I would talk to your manufactuer tech's and see what they think.

BTW the Monarchy sounds extremely musical with the BB's and I really like eliminating 1 pair of interconnects in my system. I am having a Accupuhase C200 upgraded to lower the noise floor. The C200 was extemely quiet but I am hoping for improvement. I will post a squib on my system when I get it complete in about 2 weeks. Good luck on your problem.
I HAD A TERRIBLE STATIC PROBLEM WITH A CARY SLI80.I WAS TOLD IT WAS MY CD PLAYER,IT WAS BRAND NEW (ORACLE 1500).I RECEIVED ANOTHER ONE SAME PROBLEM.SO I UPGRADED THE INTEGATED TO A PAIR OF CANARY AUDIO MONOS AN NAT AUDIO PLASMA PRE AMP AND NO MORE PROBLEM.I CAN FEEL YOUR PAIN.GOOD LUCK!!