Here's an amplifier I made, very closely based on a circuit by Randall Aiken, which had a typical Marshall preamp with one extra gain stage, and a SE EL84 power amp. Yeah it's a High Octane AX84.
I drew up the chassis on Autocad, then took it to a local shop to have their robot cut it out with a laser. I was pretty pleased with the result. I wanted the chassis to be self-contained, and just put a lid put on the top and bottom to cover things. This made it much easier to work on the amp too, as I could turn it upside down and it would lay flat without resting on the tubes or transformers. It's made of 2mm stainless steel, which looks good, doesn't rust, and is non-magnetic.
You can see how internally the chassis is divided in two. The power supply is segregated from the amplifier by a bulkhead. The high tension supply comes through one grommet, and the heater supply comes through another. I was trying to make everything as neat as possible, and hopefully by planning the layout well, keep everything quiet.
The preamp board. I got these neat PTP epoxy turret boards from Antique Electronic Supply. They've got ceramic tube sockets with gold plated holes built into them, and big brass lugs to solder on to. All the coupling capacitors are film foil types rated at 1500V. The cathode bypass caps aren't anything special, just axial. The resistors are all metal film. Resistors on the plates are rated at 350V, the others 250V. I wanted higher but hard to find locally. The heater supply can be seen dropping in from above. It's about an inch away from the board, hoping to keep any hum out of the input.
The power amp board. The 5W resistors are a bit of overkill really, but better over than under. I used solid core wire for most of this board wiring, but if I did it again, I'd use smaller more flexible wire. You can see the hum reduction resistors attached to the heater input pins. They reference the heater supply above ground to help reduce hum being induced in the input. At the top right you can see the resistor setting the bias (attached to one end of the 120ohm resistor). I could put a pot there instead.
The power supply, tucked away in its own little box. Yes there's some EVIL silicon there. The transformer was custom made to work on either 100V or 230V, so it's got some odd taps. Using the terminal board with the spade terminals means I can change taps with a screwdriver.
Here's the amplifer compartment in its entirety. All the green wires are leading the star ground. Lots of cable ties!
Both compartments together.
All these corner trusses have M4 anchor nuts in them. No self tappers allowed.
From the top you can see that the power transformer has been kept as far from the preamp tubes as possible. The output transformer is at 90 degrees to the power transformer. There's also the big stainless shield between them.
Sitting next to my homemade cabinet. The cabinet is golden ratio, polyester filled, 18mm MDF, with stainless corner braces. There's an Eminence Alnico 10" and a Jensen Ceramic 8" in there. It all sounds very nice, much better than I had hoped, and it's deadly quiet, which pleases me too.