Uploaded September 2024 | Updated September 2026, 2 weeks ago

---

This is part 4 of 4, tuning up for the first time using new Penta Labs 3-500zg with Jim Heath W6LG YouTube Elmer. Jim gets about 1500 watts out of an old Drake L4B. Initially some failures inside the amp made it look like the tubes might be defective. As you may already know, the tubes were fine.n

Please do support the channel:
patreon.com/JimW6LG
or for a single donation
buymeacoffee.com/hamcq73c

Part 1 of 4, Jim W6LG tells how he was almost electrocute in 1967 testing a homebrew linear amplifier. The point of the story is to be extremely careful when dealing with the voltages in a linear amplifier.
In Part 2 of 4, ordering replacement 3-500zg tubes for an old Drake L4B linear amplifier. Getting a matched pair that can deliver 1500 watts output with Jim Heath W6LG YouTube Elmer.
In Part 3 of 4, replacing 3-500zg with new tubes in a Drake L4B Linear Amplifier. Jim Heath W6LG talks about the process.