What is an ideal humidity for tube amps pre amps and speakers?  All around equipment?

The expert also informed me I was probably getting ice in the walls as well that's why it's best to let the humidistat control the humidity as it adjusts for outside temperature changes. 
Thanks to all. I'm in Fl so with the a/c it's usually 38 to 46% sometimes lower in the winter.
You must run your A/C almost non-stop if you're achieving those levels in FL. You might want to check the accuracy of your hygrometer. Normal "comfort zone" is between 40 and 60%, above that exists high potential for mold, below that leads to static and greater potential for airborne illness. The important thing for speakers is to avoid sudden, large shifts in relative humidity, this is especially true for cabinets constructed of solid wood or plywood.
I set my a/c at 79-80 degrees. Humidity is 38 to 48% I average 24 kwh during the hottest months and 14kwh the rest of the year. I have great insulation. The room is 18x12.5 8 foot ceilings and about a total of 1185 sq feet. I check the meter daily and keep my elec bill under 100.00 per month. Very rarely open the windows.
I live in the south too. Keep the A/C at 77 or 76 in the summer. Old drafty house. Humidity is kept at comfortable levels. What number? Who cares? If our equipment can't run optimally at comfortable temperatures and humidities then we need different equipment or a less insane hobby.
Not only does humidity affect equipment but humidity, and temperature, also affect the acoustic envelop in your listening space ( a 10% swing can dramatically change the reverberation field by messing with the response of the higher frequencies which provide much of your spatial cues ). Concert halls are generally designed with HVAC systems that can easily ( and quietly) produce constant temperature and about 50% humidity with any and all crowd configurations.