1st full tube amp Oldchen EL34

And as others have stated above.

Tube amps are high voltage devices, and can "hurt" (yes, speaking from experience...)

Only ever put one hand in the chassis at a time, unless you have discharged the caps and it is unplugged. I got a rather unpleasant shock when putting one of my DIY projects on the shelf after working on something. Fingers went under the wooden base of the amp and touched some wires. This while my thumbs were on the metal top of the chassis. 

I have a slightly bigger chinese tube amp (Willsenton) running Klipsch Cornwall IVs and without having any tube amp to compare it with I find the combination very sweet. Just yesterday I played some music I hadn’t listened to in ages and again it was sonic revelation. If I had any knowledge whatsoever about wiring, soldering, etc. I’d probably also have a look under the hood. So far I’m happy finding out how far rolling tubes can bring me. 
Enjoy this adventure!

Thanks for all the responses. After a few hours of listening I am generally pleased with the $150 spent. I may pass on upgrading as I saw the silicone inside and have zero interest in prying stuff loose. It will remain as is and be enjoyed. Tubes may or may not be my thing. Stressing over heat, bias, and high voltage may get in the way of just listening. The engineer in me may just be too curious to actually enjoy them. 

Good call on the internal mods :)

After seeing how the amp survived my friends rather “careless” treatment of the amp, I wouldn’t worry too much :)

Oh, and he kept it in a confined space in an entertainment unit. Got really toasty in there!

Live with it for a bit, see how you like the sonic signature. 
 

And tubes, the “maintenance” of tubes and the care one needs to observe, isn’t for everyone. Nor is the sound they produce. That’s in your hands to decide :)

For years I sold new Jolida and Black Ice Audio gear. And I have sold a lot of vintage SS gear. I have auditioned a lot of gear over the years. I bought an Old Chen EL34 amp. Very good build quality. Best sounding amp I ever heard. Self Biasing. Many people wonder if a Chinese made amp is safe- what? Why not? I have a set of kitchen knives made in China- 20 years old and still razor sharp. Also, silver wiring makes for very clear sound, but amplifies the upper frequencies and is not so good with bass. I prefer good quality solid copper. The Old Chen EL34 is not junk. The transformers do not get hot, only a bit warm- that is a sign of good transformers. And one does not need to spend $3000 to get a good SS amp. Any piece of gear can only be so good. Beyond that you are throwing your money away.