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Tube amp for car audio

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New Member
Hi. I would like to design a tube amplifier for car usage. I understand that i'll need to use a switched-mode power supply to boost voltage from the 12V to whatever the amp requries. I take it i could merely use an off-the-shelf power supply. In terms of the amplifier, can anybody recommend any good approach to take?
I was, for a time, thinking about using a simple tube guitar amplifier, but i'm not sure if it would be a good idea.
Durability is obviously an important factor, and i'm concerned that the delicate tube glass could easily fracture if going through a pothole, etc.

Can anybody inspire me?


Nigel Goodwin

Super Moderator
Most Helpful Member
I don't know about 'inspire' - but it's such a completely stupid idea! - why on earth would you want to do such a thing?. Valve amps are massively inefficient, have high distortion, high noise, poor frequency response, and only have relatively low output powers.

Many guitarists like all these failings, but it doesn't have any use for an in-car amp!.


New Member
Yeah voices would sound absolutely terrible...unless you were playing guitar while driving this seems stupid.


Active Member
Some thoughts or comments -

A. The construction/component requirements for a vacuum tube device can be challenging for mobile applications. Not all tubes like to be shaken/jolted.

B. Amateur radio operators were faced with the same challenges and you may find power supply designs in amateur literature - especially when transistors started replacing tubes. I wasn't thinking of the electro-mechanical vibrator supply but rather something solid-state.

C. My thoughts on the debate on sound quality (solid-state vs tube): you need to define what quality means. In my opinion, a high quality amplifier will faithfully reproduce the input exactly with no distortion - within the limits of my ability to hear the output. That can and has been done quite well with both tube and solid state amplifiers. Factor in cost, reliability, power handling and there is likely to be a clear winner.

D. Sound quality and distortion appear to be points worth discussing - based on the debates I witness. I assisted a young man in his final EE degree project - a tube guitar amplifier. The power handling end met my definition of high quality and the difference between it and a solid state version might be incredibly small. The pre-amps/front end were a different story. They are high quality by some measures however they were designed to produce distortion/harmonics to make the guitar sound just the way some people like it. It is my understanding that tubes are different than solid-state devices in this respect (intentional distortion). I would think it likely that a solid-state amplifier could be carefully designed to accomplish similar behavior. By the way, the guitar sounded great.

The whole point of the discussion on quality and distortion suggests you may not want to use a guitar amplifier as an amplifier for your CD player - unless you really do want that behavior/sound.


I don't know, perhaps he's a street performer.

You could buy an inverter and build a normal valve amplifier.

However I can understand the requirement for something light weight so a DC-DC converter sound like the best way to go but you need to know what voltage and current you need first and you'll need a lot of filtering on the output so it doesn't interfere with the audio.

Also be warned that valves are extremly fragile and can be broken all to easilly by rough handling.
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