Is it still possible to build a vacuum tube computer?

Back in the 1940s to the very early 1960s computers used vacuum tubes as logical components. They were replaced by discrete transistors, which were replaced by integrated circuits.

There are still companies making vacuum tubes, something I’m assuming individuals effectively cannot do if only because of the costs involved. Assuming a bunch of hobbyists came upon complete and correct plans for a vacuum tube computer and decided to save their pennies to buy all of the hardware and build it, could they? Is anyone making the correct types of tubes anymore?

A reconstruction of Collossus is on display at Bletchley Park. It looks like it was built by a hobbyist too (although he did have some help from the original creators of Collossus).

I wouldn’t doubt it, vaccuum tubes must be in use in some equipment. Obviously it would be impractical but it could be done.

But there are different kinds of tubes. I don’t know what specific kinds were used in computers and I don’t know if they’re still being made.

Szlater: Fascinating! Thank you! However, it seems the guy ‘cheated’:

He was using (very) old stock. Maybe that’s OK, if there are a ton of 1940s-era tubes left in working condition. But I’m more interested in someone building a computer using tubes made recently by one of the plants supplying amp builders.

Ahh I didn’t see that.

I suspect that they were trying to make as faithful replica as possible as the original was destroyed after the war on the orders of Churchill.

Resurrection is the journal of the Computer Conservation Society. It might be of some help too.

To build a computer you need logic gates, and you can build logic gates out of just a handful of very common types of vacuum tubes. Tubes aren’t exactly at the height of popularity these days, but they are still being manufactured. So, sure, you could easily make a computer out of tubes.

engineer_comp_geek: Fascinating. It’s amazing to think that by cannibalizing enough amplifiers you could build a computer. (Well, the RAM and CPU part of one anyway. I/O and long-term storage are left as exercises for the reader. Cost of electricity not included.)

Why not use relays? They are still widely available.

Heh, Tony Sale is mad as a box of frogs. I love his site.

Obviously I’m not planning to build one. I’m not competent to wire a kitchen. I just got curious about the whole idea when I found out that companies in Russia were still making tubes.

Compared to even primitive tubes, relays are slooooow. Yeah, you could do it, but why bother? Plus the noise of all those contacts clattering would drive one crazy, I would think.

Oh, no - It would make a beautiful noise!

You wouldn’t want to build the RAM out of vacuum tubes. Williams Tubes used to be popular, and my very first logic lab project was building a memory out of an acoustic delay line. Using cores would be okay also, but I wonder if those are made any more.

I wonder if vacuum tubes made today are more reliable than the ones made 50 years ago.

You know how hard it is to find Mercury delay lines?

Being an electric guitar player, tube amplifiers are still very sacred and the number one choice of any musician worth his salt. Anyway, that is one reason tubes are still made today.

Voyager asked:

If you ask this question to any guitar player they will give you an emphatic NO !!!
And it just doesn’t apply to tubes. Oh no. Anything made back then is so much better than you can get today. The reasons?? The guy who founded the company left it to his kids, who had no business sense whatsoever. The guitar wood has become extinct and there’s no possible way to get that sound from anything other than that particular wood. They made things differently way back when, before the “suits” came in with their corporate mentality, etc. :slight_smile:


Way to practice your reading comprehension there, champ.

Explain, please. What am I not comprehending?

The original post was tongue-in-cheek.