• 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.

vibration resistant preamp tube

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Back in the day, Sylvania developed Loctal tubes, specifically for use in mobile applications. Quite a few Loctal types are electrically equivalent to commonly used Octal types. The 14xxn bunch should be fine running off a car's electrical system.

A quick look at a 26E6WG data sheet suggests the type is easy enough to drive. A 14F7 (12SL7) for the voltage amplifiers and a 14N7 (12SN7) for the phase splitters in a setup resembling the Dyna ST35 should be OK.
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Shock mounting even loctal tubes wouldn't hurt. Could be a floating subchassis in the box.

Miniature 6.3V types either Russian or U.S. in origin are a great option and very rugged - designed for harsh environments. The U.S. 6021 is a quite decent sub in applications calling for 6SN7 or 6CG7 types. (observe lower voltage ratings) Higher mu 5744 is another possibility, but linearity is only fair so use in amp with overall or local feedback. For power output I would use 6BQ5 or if you have space perhaps the loctal 7C5 or 14C5 which are 6/12V loctal versions of the 6V6 respectively. 14C5 are currently under $5 if you shop around.
Thanks for the good ideas. I was thinking of rectifying and filtering the output of a power inverter I have onhand but am not using. Was considering high mu LTP to maximize the usage of the limited voltage.

Looked at something like 6N2P-EV but the loctal idea is intriguing. I had completely forgotten about those. Given their intended application one would presume that microphonics was a major design consideration.

I am not sure what voltage we will get from the inverter since it probably is no where near sinusoidal.
So if a did decide to use some of my 26E6WG stash to build a car amplifier what would be some good ruggedized and vibration resistant small signal tubes for VAS and PI stages? I suspect our Russian comrades must have some appropriate choices. :)

6С17К-В (6S17K-V) is absolutely silent, but it has pretty high input currents. Also, for mobile equipment were designed such tubes like 6Н16Б-В 6Н17Б-В. 12Ж1Л, 12П17Л. ГУ-50.
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