• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Hundreds of 6AL5s


Paid Member
2003-06-12 7:04 pm
Maine USA
> any possible use for hundreds of 6AL5s?

Vacuum-tube digital computer.

Oh, sure, you need some twin-triodes too. But early computers (vacuum, germanium, silicon, and even DTL and TTL chips) use diode-logic as much as possible.

It's been a while since I ran optimizations like this. I'm gonna speculate that "hundreds" of dual-diodes could build an 8-bit full adder. Two sets of 8 toggle switches, one set of neon-lamp outputs, and you can add any two numbers from 0 to 255 as fast as you can work the switches.

If you lived in the land of 120V: put about 20 heaters in series, all 40 plates in parallel, you could build a death-trap trickle-charger to keep your lawn-tractor battery topped-off all winter. "Death-trap" because you have a 50:50 chance of having 120VAC on the battery terminals. This is bad enough, I don't think you should consider 40 bottles for a 240V battery trickler.

> VTVMs. Every one I've ever seen has a 6AL5 in it.

Yeah, but I've never seen one fail? Unless you blow it by probing your 211 amp plate, the total ampere-hours is about zero per decade.