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From the Q&A

With TJ Byers


Lafayette Tube Amp Restore

Question:

I'm currently restoring an old Lafayette two-meter 6146 tube amp. It's in pristine condition, minus a plate transformer and a few unknown connections, specifically pins 3, 5, and 6 on both tube sockets. Do you have any knowledge of these pins and what their function might be? I also need to know what the plate voltage for both of these tubes should be.

Tim Terrorisi
via Internet


Answer:

The 6146 is a small, lightweight beam-power pentode designed for service as a very high-frequency amplifier. Its high power output, low driving power requirements, and sturdy construction make it ideal for mobile and compact equipment. Here are the specifications you're looking for.

Shielding and effective RF grounding are facilitated by the cathode (pin 1), grid 3 (pin 4), and an internal shield (pin 6), all of which are connected inside the tube. Isolation of the output from the input is further enhanced by a top-cap plate connection. The maximum plate voltage is +750 volts, but +500 volts is considered optimum. The voltage on grid 2 (pin 3) should be half the plate voltage or +250 volts, whichever is smaller.


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