i know a fair amount about tubes and tube amps but im still cloudy on some details
like: what is the difference between a rectifier tube and a regular tube? and are they interchangeable?
what about kt66 vs el34 vs 6l6gc pros? cons?
how about those other ones that can be exchanged for 12ax7's some vox amps have them?
whats the difference there

please bestow all the knowledge you have upon me or at least pos a link to a place of such knowledge
There exist three types of tubes, at least in guitar amp circuits:
'Preamp' tubes usually of the 12A?7 family, where ? can be X,T,Y,U, etc. The 5751 is a notable addition. These are small tubes, and are used for preamp amplification, phase inversion, effects loop drivers, and tremolo/reverb drivers. They can, for the most part, be interchanged.

Power tubes are larger tubes. Amps, with rare exception, have either one, two, or four power tubes. They have names like 6l6, 6v6, 5881, EL34, EL84, KT66, etc. They are somewhat interchangeable, but not usually to any practical extent; some amps can switch from 6l6 to EL34 with only a bias adjustment, and there are converters to change many tube type amps to El84s to lower volume, but the difference in tone is often much less pronounced than one might initially expect. The tube type matters far less than the circuit it's in. For example, a Twin reverb and a dual rectifier can both use 6l6 tubes, but the difference in sound is rather obvious.

Rectifier tubes convert power from AC to DC. The most popular rectifier is the GZ34(5AR4), but others get occasional use: 5U4, 5Y3, EZ81.
if your amp doesnt come with rectos can you put them in without dynamite?
The two primary things that determine which power tubes you can use are the heater current draw and the plate voltage. EL34's (typically brighter sounding) and 6L6GC's (typically darker sounding) are close enough that they can be interchanged in most amps with only a bias adjustment. Tubes like the KT66 and KT77 typically have a larger heater current draw and can withstand higher plate voltages (they tend to run hotter than EL34's and 6L6GC's) however the numbers are close enough to where most 6L6GC equipped amps can run KT66's and most EL34 equipped amps can run KT77's. The 5881 tube is a 6L6GC variant that is almost the same but was manufactured for industrial use as opposed to consumer use. Also note that some amps can use 6550's and KT88's though many can not, the plate voltage runs so high that it can cause damage to the transformers in some amps (KT88's can also produce up to 50 watts per tube versus the 30 from a 6L6GC or the 25 from an EL34).

There's tons of information on tubes floating around, some in this forum and much more elsewhere. It's worth the time to go researching a bit.
ESP LTD EC-256 and a Fender Deluxe VM
Quote by MOLAAAK
if your amp doesnt come with rectos can you put them in without dynamite?

It will have a rectifier anyway, it just doesn't necessarily have a tube rectifier. In fact solid state rectifiers generally perform much more efficiently than tube rectifiers, and they aren't in the signal path so a solid state rectifier doesn't negatively affect the tone. There are some people who have replaced solid state rectifiers with tube rectifiers and vice versa, so it can be done.
ESP LTD EC-256 and a Fender Deluxe VM