The Museum of RetroTechnology | Hacker News Reader

The Museum of RetroTechnology

douglas-self.com

I remember when microphones were physically dangerous. It mentions carbon microphones with the main supply voltage going through them: http://www.douglas-self.com/MUSEUM/COMMS/mechamp/mechamp.htm.... But even into the 80s, microphones plugged into portable vacuum tube amps sometimes ended up with the plate voltage (200+ volts) on them and shocked people when they touched them. Stage performers usually brushed a mic quickly with a finger before putting their lips close to it, to make sure it wasn't electrically hot.

I wonder if it resulted in people being more careful what they said near a microphone too.

Oh, mics are still dangerous. I play a lot of restaurants where you get odd hums... one way to "deal" with that is to remove the safety ground on your guitar amp.. of course, there is then a possibility that there is a difference in potential between yourself as grounded through the amp and yourself as grounded through a microphone... you don't need a carbon element or a tube amp to get badly shocked that way. I and a lot of my dirtbag musician friends still will touch a mic before using it.

Have you tried using an isolation transformer?

http://www.shure.com/americas/support/find-an-answer/transfo...

wow, makes live performance even more 'impressive'

Douglas Self is the author of some really excellent books on audio electronics. Especially "Small Signal Audio Design" (https://www.amazon.com/Small-Signal-Audio-Design-Douglas/dp/...).

I remember pneumatic tubes. Only a few years ago, Costco was still using them to deliver checks/cash to their tills. I cannot say exactly when, but well into the 2000s.

Drug stores near where I live still use them in the drive-throughs.

I was amazed / impressed to read that some of the pneumatic tube systems in cities were operating for over 100 years. That's a long time for any given technology.

The "Combat Cutlery" was absolutely worth the click.

From now on I will be a little disappointed with every spoon I use, that is not also a firearm.

Visit the Prison Museum in Huntsville, Texas.

You'll be amazed by the deadly and complicated things that can be built with little material but a lot of time.

I appreciated the bit about pneumatic tubes. For whatever reason, I have been itching lately to find technical details on modern packet-switched pneumatic tube networks [1]. They're still used in hospitals apparently.

[1] https://youtu.be/W39qQE5jqWk?t=55s

thanks for this, I learned something I never heard of before: compressed air power grid http://www.douglas-self.com/MUSEUM/POWER/airnetwork/airnetwo...

old times weren't so low-tech, this feels like steampunk^2

I'm really digging how the top entry is the Shakespeare Mangle, a cipher machine for conspiracy theory gibberish.

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