• 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.

Is anyone using the AC2/HL indirectly heated triode

That's an old radio triode. I collected a lot of these radio triodes and some were pretty good, like REN904, TDD4, AC2 for instance. But they all have high Rp so I never used them in the end. I found other solutions. I still have quite a few of these tubes and they are all for sale cheap. PM me if interested.