Why don't 12AX7 heaters in Eico HF-85 preamp glow?

Tubes Asylum

Questions about tubes and gear that glows. FAQ

The heaters of the five 12AX7 in my Eico HF-85 preamp barely glow, if at all. None of them. Are they being run at a lower voltage?

Regardless, the piece works well and sounds great. I like it more than my McIntosh C36 (no surprise). Maybe as much as my inactive C22...can't tell...the C22 needs a visit to the Audio Classics bench.

Your interest may vary but the results will be same. (Byrd 2020)

I can't compete with the dead. (Buck W. 2010)

Cowards can't be heroes. (Byrd 2017)

Why don't catfish have kittens? (Moe Howard 1937)

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Topic - Why don't 12AX7 heaters in Eico HF-85 preamp glow? - Byrd69 07:05:39 04/30/23 (6)

RE: Why don't 12AX7 heaters in Eico HF-85 preamp glow? - Tre' 10:28:27 04/30/23 (5)

Oops...Eico on my mind - a correction - Byrd69 11:27:01 04/30/23 (4)

The PAS runs the 12ax7s on low DC heater voltage (11vdc) and ... - Tre' 12:15:26 04/30/23 (2)

RE: The PAS runs the 12ax7s on low DC heater voltage (11vdc) and ... - Byrd69 12:43:52 04/30/23 (1)

You're welcome nt - Tre' 13:36:20 04/30/23 (0)

RE: Oops...Eico on my mind - a correction - Jonesy 12:07:18 04/30/23 (0)

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