What is Reddit's opinion of Valve Amplifiers?

From 3.5 billion Reddit comments

First, this isn't a "get off my lawn post" :D

This is a neat example of the generational gap on electronics. As assembly techniques progress, it's fun to see what the latest generation of hobbyists/professionals are familiar with, it seems like there's probably a curve with a hump extending back about 2 generations of technique. So it's really cool to see folks posting here that haven't seen this sort of thing, whereas folks that came into electronics as late as say, the 80s are reasonably likely to be familiar with it.

Of course there are niches that delve back farther. There are people just now starting to dig into guitar amplifiers for example, to whom this is par for the course.

If any of you are newer to electronics, and are interested in this sort of thing, it's a really fun journey to see how earlier stuff was made, and how design and assembly techniques revolved around the devices available at the time. For example, BGA packages today push us into 4+ layer PCBs, you pretty much see that as a default with those types of devices. Rewind 50 years, and big ol' tubes suggested their own construction techniques like the sort of point-to-point stuff you see in the image attached to this post. Nowadays we of course use PCBs with tubes, but back then the hardware was so big, labor was less expensive, and production numbers were so much lower that hand assembly of this sort of thing made a lot of sense!

And don't get me started on tubes themselves. There are more complete ways to describe this, and I'm sure others will add to my post here, but think of a triode like the 12ax7 as a voltage-controlled-transistor-thingy. It's not really that mysterious! In fact, if you're familiar with basic transistor circuits it's a hop, skip, and a jump to doing all sorts of fun things with tubes. Yes the voltages are higher (and read up on HV safety before you start messing around with this stuff!) but a lot of stuff is very similar. Biasing up things, impedance matching, all that stuff can reasonably be said to be the same from a fundamental perspective. Electrons are still electrons!

<We interrupt this thread for the obligatory car analogy>

You can think of this stuff like looking under the hood of a 1963 split-window Corvette. Yeah, there's no ECU. No forced induction. Timing is completely mechanical. But same as today, the fundamental concept of internal combustion is the same.

If you're interested in tube stuff, I would highly HIGHLY recommend Morgan Jones's "Valve Amplifiers". It contains a great overview of how these glass envelopes control the flow of charge and shows a lot of great circuits courtesy of a real-deal BBC broadcast engineer from back in the day: https://smile.amazon.com/Valve-Amplifiers-Morgan-Jones/dp/0080966403/ref=sr_1_1?ie=UTF8&amp;qid=1542172758&amp;sr=8-1&amp;keywords=morgan+jones+valve+amplifiers (not an affiliate link, also check your local library). There are also some great YouTube videos as others have mentioned, including some neat ones showing how they're made.

Also, if you choose to partake, don't get put off when you Google for tubes and see a bunch of boutique/NOS stuff catering to the musician/audio crowd! That stuff is expensive, but there are some really decently-priced tubes available from overseas. The former Soviets in particular continue to produce new glass, some of which is a direct cross-reference to parts you'll find in classic schematics as well as surplus stuff that is pretty decent in its own right.

Have fun! Be safe!

I learnt a lot from Mr Carlson's Lab and

Blueglow Electronics channels on Youtube.

Also, if you're interested in the audio side of tubes, Valve Amplifiers by Morgan Jones is a great book that covers everything you need to know.

For the history, there are some great documentaries on Youtube as well:

Vacuum Tubes 1943 Training Film

The Mullard Story

Vacuum Tubes Educational Documentary

And this book is a great read on the history of tubes in America: Saga of the Vacuum Tube

For software, I recommend PSUD2 for designing tube amplifier power supplies

If you're interested in building a tube amplifier, these Elekit kits are very high quality Elekit TU-8900 300B Amplifier

One last note, please be careful if you're just going to "dive in". Tube circuits contain LETHAL voltages, often 400V+ up to the kV range. Don't go playing with them until you properly understand the dangers and how to safely build and operate vacuum tube circuits.

Good luck!

I have morgan jones’ valve amplifiers https://www.amazon.com/Valve-Amplifiers-Morgan-Jones/dp/0080966403 .