Beauty of old electrical and measuring things, etc.

[Ivan Nikiforov]

I have such a device. A galvanometer with an optical pointer. This is a very sensitive device. It reacts if a magnet is simply brought closer to the wire. This device has an amazing history. In 2000, when I was a student, my classmate worked as a watchman at a municipal landfill. One evening I came to his office and he showed me various things he had found in the landfill. This device was among them. My friend didn't find anything valuable in it and wanted to throw it away. I asked for the device for myself. Only the incandescent lamp was defective. This device allowed me to conduct many experiments and allowed me to learn a lot about the nature of electromagnetism. The research I am currently doing would not have been possible without this device

 

[Baluncore]

That appears to be a "ballistic galvanometer".
https://en.wikipedia.org/wiki/Ballistic_galvanometer

 

[khaledsalman]

Absolutely love this thread. There’s a timeless elegance in old electrical meters and devices—each piece tells a story of engineering with soul. At [Company reference redacted by the Mentors], we often come across vintage panels and enclosures during restoration or upgrades, especially in older industrial buildings around the Gulf.


Interestingly, we still find original Tapes used for insulation—some of them cloth-based or rubber types that stood the test of time. It's fascinating to compare those early materials with today’s modern PVC and high-performance Tapes that offer far better durability and resistance.


Restoring old equipment isn’t just about function—it’s preserving history. Hats off to everyone here keeping the legacy alive.

 

[DaveE]

‘Hands weaving magnetic-core memory, IBM, Poughkeepsie, New York,’ 1956. Photograph by Ansel Adams.

This photograph was made on a commercial assignment for IBM.

PS: my rough estimate, 3Kb

Also this from Wikipedia:

 

[DaveE]

I love this old steampunk data sheet. Especially the draftsman lettering. Thank god I never met one of these tube amps IRL, they look like a PITA to a guy raised on ICs.

http://www.philbrickarchive.org/k2-w_refurbished.pdf

 

[Baluncore]

Thank god I never met one of these tube amps IRL, they look like a PITA to a guy raised on ICs.

The 12AX7 continues to be used in guitar amplifiers today. I don't know why they worry you, it is just a matched pair of N-channel FETs, in a hermetic glass envelope, with a 12V pilot lamp.

 

[DaveE]

I don't know why they worry you

It might be that I think ±300V power supplies are a PITA. It might be the reliability of things that require heaters and vacuum seals. It might be that they are just really big and expensive for what they do. Maybe it's about supply chain and manufacturability issues. The market place has voted, and tubes like this lost a long, long time ago.

It might also be that you only see this sort of thing in the audiophile world. I'll spare you my diatribe about audiophile opinions about electronics, mostly based on my dislike of marketing types, except to say it's an outlier. YMMV.

But, I love the historical part of the technology and the data sheets made by hand!

 

[DaveE]

Perhaps the most risqué HP ad. Circa 1972. I recall this from a poster in the hallway of the Caltech EE building when I was an undergrad. Somehow it was moved to a hallway at Stanford, but I couldn't won't say how.

PS: That's an HP5451A/5466A Fourier Analyzer, before the computers took over.

 

[nsaspook]

 

[Borg]

Minivac 601 Simulator - A 1961 Relay Computer Running in Your Browser
https://minivac.greg.technology/

 

[davenn]

‘Hands weaving magnetic-core memory, IBM, Poughkeepsie, New York,’ 1956. Photograph by Ansel Adams.

This photograph was made on a commercial assignment for IBM.

View attachment 361331

PS: my rough estimate, 3Kb

Also this from Wikipedia:
View attachment 361332

my piece of magnetic core memory :)

 

[NTL2009]

It might be that I think ±300V power supplies are a PITA. It might be the reliability of things that require heaters and vacuum seals. It might be that they are just really big and expensive for what they do. Maybe it's about supply chain and manufacturability issues. The market place has voted, and tubes like this lost a long, long time ago.

It might also be that you only see this sort of thing in the audiophile world. I'll spare you my diatribe about audiophile opinions about electronics, mostly based on my dislike of marketing types, except to say it's an outlier. YMMV.

But, I love the historical part of the technology and the data sheets made by hand!

But as mentioned above, tubes are desired not just by some audiophiles, but also for guitar amplifiers. Most electric guitarists use amplifier (and speaker) distortion as part of the sound. I'm not saying you can't replicate a tube amplifier with solid state, but there are a lot of inter-related aspects to that sound. Even things normally considered outside the signal chain, like replacing tube diodes with silicon diodes. I've been told the different impedance curve of the tube diode results in a different sag of the power supply, which then changes the clipping/distortion over time as a powerful note is held. And it may not be as simple as adding resistance to the silicon diode, as there is probably a non-linear curve.

These might not be obvious to many listeners, but the guitarist responds to what they hear, and play a little differently, so they can be aware of it in a way the listener really isn't.

Now there are software models of guitar amplifiers, I haven't looked into those in any depth as to how accurately they replicate the hardware, and of course, opinions will vary.