This Philips QB 3.5/750 Tetrode vacuum tube is designed for use as a High Frequency amplifier and oscillator. It has an output of around 750 watts!
I received it as a gift some years ago and it's been sitting in a box in want of a new home. Since I'm not going to put it into service, I thought I would make up an acrylic display housing for it, so now it sits in my lounge room where I can enjoy it!
This is a big tube - Really big! The tube is 145mm high x 87mm wide.
Want to see what this tube looks like running? Check out this!
This 1000w amp has two :)
I found a data sheet on line with a sketch of the base, so was able to transpose this into CorelDRAW. I lasercut the box with enough clearance for the tube to 'float' in the middle. The Philips logo is engraved into the inside-surface of the sides.