First vacuum tubes are not preferred by audiophiles because they like the sound of non linear devices as opined by someone above.
Just the opposite in fact. Audiophiles use them precisely because they ARE the most linear amplifying device available.
No solid state device competes with a triode vacuum tube when it comes to linearity. And for home audio, linearity is important.
Its not the only important parameter, but it is one of the most important.
The problem is… it’s costly in terms of power, size, weight and electrical efficiency to use vacuum tubes for home audio.
For home audio power amps you also need to match the high impedance output of the tube to the low impedance of a speaker.
This means in most cases the use of an output transformer. In addition to being difficult to design well, output transformers add to the overall size and weight of an already large and heavy amplifier.
The only folks that use tubes for the sound of their non linearity are the guitar amp folks.
And this only happens when the amplifier is purposely overdriven into its non linear operating region.
This produces a distortion that guitarists from Jimi Hendrix on up to current day talent especially love.
There are tons of solid state devices on the market that try to emulate that special distortion that overdriven tubes make.
With regards to the Mig fighter using vacuum tubes, it’s true, at least from what I have heard.
The Mig-25 and perhaps others used vacuum tubes in its power supply that supplied the avionics.
That tube is called a 6c33-b (and /or other variants) and has been made in Russia (only) for many years.
It’s built like a tank.
And since the opening of Russian markets after the fall of the Berlin wall, the tube has been available to western markets.
The biggest demand is from the audio crowd as the tube has some very unique characteristics.
I have about 20 of them and indeed…. they are monsters.
Thats one laying in its side next to a coke can and as seen in a home audio amplifier. Those nipples you see at top are the top ends of tube pins that
start at the bottom oof the tube and go all the way thru the tube to the top and are buried in glass to keep microphonics and larger vibrations (like you would find in a jet fighter) from having an adverse effect on electrical performance.
A beast.
Curt
