If you’re old enough you might remember seeing one of these in a drug store, grocery store or even Radio Shack. You could pull all the tubes from your radio or TV, put them in a paper bag, and take them down to your local store to test. And hopefully you wrote down which one came out of which socket. Once you found the bad tube or tubes, the store proprietor would unlock the bottom and find new replacement tubes. And the price list is taped right inside the door.
I remember using these. You didn’t have to write down which tubes went where because the store had a sheet of stickers in number pairs, one for the tube, and the matching sticker for the socket.
Memory Unlocked. We had moved into a house that had an old 60s tube radio built into the wall, it was broken, but my dad went through steps to sort out the issues and pulles a few tubes out. I recall the door with the chart of valve types.
The radio/amp sounded great once fixed. It had these two luninous stripes that you watched as you dialed in a radio station. It was a tuning aid. you tried to get the lines as close as possible to know you had matched a frequency, but if you over dialed the stripes dissapated, and you had to scroll back a bit.
There are also testers in carry-cases.
And there are companies that sell tube amp kits with very detailed instructions, some based on the Dynaco specs and designs from the 50s-70s. Repro parts are still made. Dynaco sold Dynakits back then.
The tubes are mostly Chinese or Russian made, possibly some in Ukraine.
Thing to remember is they run very high voltages and they can self destruct when one’s back is turned.
This vendor has been around for decades and has a supporr forum… http://tubes4hifi.com/
I have an old (probably '60s) hifi amp. It’s awesome. Replaced the selenium rectifier with silicon, replaced a few caps, and put fresh tubes in it.
It sounds…basically the same as modern solid state stuff to my untrained ear. It’s pretty cool that in a sense we “solved” the problem of amplification back then. Most of the speakers of the day were probably complete crap by today’s standards (unless you had something upscale like a pair of AR-3s), but a well designed amplifier from the era holds up well.
