This outta get under the tubies skin..

ProAc_Fan

Addicted Member
looky looky a CAR tube amplifier.
ebay auction

I'm not a tubeaphile but I'm not against tubes either. Wouldn't the dubious nature of car voltage and the inherent fluctuations inherent in car voltages be detrimental to the use of tube amps? Could this really survive long in the trunk of some punks Honda Civic?

Mike
 
um...no...tubed car radios have been around forever...that's what they started as. Although...it's tough to find them any more...gotta go to swap meets and stuff.
 
This amp uses a solid state inverter circuit to derive the 450 volts B+ for the tube circuitry. In the older car radios they used a mechanical buzzer type vibrator and iron step up transformer to run the voltage converter. Ohhhhh shoulda mounted that under the drivers seat! :) When the early germanium output transistors replaced the output tube in car radios they were able to run the rest of the tubes on just 12 volts DC plate voltage.

The biggest problems I see in a trunk environment will be moisture and dirt degrading tube socket contacts and coating the circuit board with slightly conductive dust that will be humidity sensitive. Vibration might loosen the tubes if retainers haven't been employed (simple solution). Some tubes by the way they are made won't handle vibration as well as others on the long haul. A well built tube amp should be able to survive living in a trunk that isn't open underneath to the road IMO.

Another potential problem is that some purchaser is likely gonna try to park as close to a nuclear test as he can to try to disprove a statement made in the sales literature about survivability in the event of a nuclear blast. Can't change human nature.

Rob
 
Gone,

I was thinking more the pleasure from the vibrator than the heat. :)

The 300B has a rather thin fragile filament. I wouldn't want to bounce one of these around, especially given the prices they command these days. This is clearly a better environment for indirectly heated cathode tubes like 6L6, KT-88, 6550, 6146 (they ran 6146's in early mobile VHF car phones)...etc. Maybe a set of 6AV5's wired triode to simulate 2A3's?

Rob
 
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