Many high end car makes feature audio systems designed by famous audio firms (like Bose, Mark Levenson, etc.). Has anyone yet offered a system which utilizes vacuum tube based amplifiers?
Vacuum tube amps are supposed to offer the best sound-could anyone tell in an automotive environment?
The “better” sound of tube amps is a complete load of crap. But, if you’re the type of person that buys into all of that nonsense, there are several manufacturers who make car amps that contain tubes. Butler and Milbert are the first two manufacturers that show up on google.
I wonder how the significant power draw of a tube amp would effect the car’s fuel economy.
I had a car with a vacuum tube amplifier once. But that was only because it was build before the invention of the transistor. It was damned annoying to have to wait for the radio to warm up before it started playing.
I thought this too, too much power. But the Google’s (and Car and Driver) tell me that indeed there were many years of tube-only car radios until 1963 when the first all-transistor one was introduced. Apparently they developed some low-voltage tubes or designs (still reading this one: Space Charge and Other Low-Voltage Tubes )
I’ve never been part of the audiophile world. But I thought if you were in it at the level where you were using vacuum tubes, you’d already have reached the sound room level. You’d dismiss the possibility of achieving “perfect” sound in an environment like a car.
I only looked up the specs on one, and it drew 1.8 amps at idle, or roughly 22 watts. That’s low enough that it’s going to be hard to measure in your mpg. A lot of car headlights draw more power than that.
It takes about 40 hp to drive a normal car on a flat road at highway speed. This is about 30,000 W. Even if the amplifier is consuming 100W extra, we’re still only talking about fractions of a mile per gallon difference.
**troub **beat me to it. There have been plenty of tubes designed with 12 volt filaments and higher voltage (eg: the 300 or so volts for plates) was not hard to come up with thanks to vibrators and step-up transformers that worked remarkably similar to the car’s distributor points and ignition coil. They sounded much like canned bumblebees when running.
no, because it would be dumb.
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the “superior sound” belief for an audio amplifier* is garbage. Even when not overdriven, tubes will add some measurable distortion to the signal. even a mediocre solid state amplifier should have total harmonic distortion numbers well below 0.1%.
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tube amplifiers have a practical limit to how powerful they can be, thanks to their limited capacity to dissipate heat away. this plus the heat from the cathodes would make them incredibly difficult to keep cool when packaged where OE car amplifiers/radios are.
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tubes are fragile, with short lifetimes. automotive manufacturers typically specify a design life of 10 years, 150,000 miles. I’d say it’s virtually impossible for a tube amplifier to meet that, especially when the validation testing requirements involve things like having to operate at -40°C, +85°C ambient and all points in between, and endure vibration testing which would rattle your teeth out.
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the tubes used for the output stage cannot drive speakers directly, there needs to be a (beefy) transformer between the output tubes and the speaker. adds cost, size, and weight. solid-state amps have inherently low output impedance and drive speakers directly.
so no, nobody is doing it because they would be underpowered, hot, heavy, and insanely expensive for no perceivable benefit.
- I’m specifically ignoring amplifiers for musical instruments e.g. guitar amplifiers, because frequently those are intentionally overdriven by the player and the resultant distorted sound is desirable.
The transistor was invented in 1949 (IIRC). It took a few years for manufactures to re-tool.
Until they did, everything used tubes - including the first car radios ca 1938.
(and you know the folks who couldn’t afford them were bitching about what a safety hazard they were).
up until the 1970s, cars with radios had one channel, with the single speaker up on the center of the dash. some could have had two, with the second in the back on the parcel shelf. they had a few watts per channel at best.
with most modern cars, the radio has a four channel amplifier IC made by a number of manufacturers (the ST TDA7388 is an example) which can output 16 watts x 4 channels. branded audio systems use a separate amplifier which can have anywhere from 6 to 20 channels of amplification. you ain’t going to do that with valves.
We’re probably all talking about at least two different things here.
In the 50s and early 60s car radios were tube amplified. But they only had a couple watts of output power on their single, not stereo, channel and one or two small tubes total. By small I mean like 2 knuckles of an adult little finger. And the radio cases and the dashboards were hardly packed in the ginormous blimbmobiles of the day so there was plenty of room for airflow.
Conversely, if somebody wanted a modern tube-operated bass blaster that could rattle windows 3 blocks away, and wanted that as OEM in-dash equipment, well now that ain’t gonna happen. There’s not room for the components nor room for cooling.
I suspect the unit **troub **found in post 4 isn’t very powerful, and/or includes transistors for the serious grunt work of making power. My admittedly cursory Googling found a bunch of old ebay sales and a couple of clickbait teaser articles, but no real specs or details.
Some aftermarket builder could sure do it though. You might lose the back seat or trunk or both, but it can be done.
Late add: A search on Panasonic.com official website for troub’s model number returns nothing. Not even on the support page where it says to enter a model number. I wonder what year(s) they were built?
while I think you and I are mostly on the same page, I need to point out that the Panasonic head unit troub linked to was released more than a decade ago. and I think it was Japan-only when Panasonic was actually selling the thing.
Agree we’re in agreement.
You and I were simultposting, mostly because I forget to refresh stale tabs before launching into my speechifying. Bad habit. I apologize if it appeared I was nitpicking or piling on with your immediately previous posts.
People might remember a once well known electronics manufacturer, one that once ruled the roost on mobile phones, and had a massive semiconductor arm. Now reduced to essentially nothing more than a badge-name. The good assets long since sold off. I wonder if anyone thought where their name came from? I refer of course to Motorola.
The advent of transistors didn’t instantly render tube based designs obsolete. Early transistors had a huge range of restrictions, and it took quite some time before cheap, reliable and useful power handling came to be.
The whole thing about tube sound comes in two flavours. A misguided idea that tubes have an inherently better transfer function, and thus can be used in ways transistors cannot with a sort of purity of purpose that translates to the sound. The other is simply that tubes do have a different transfer function, one that can be exploited to craft the sound. In the extreme you get tube based guitar amplifiers that are designed from the outset to distort, sometimes tearing the waveform into shreds, othertimes just adding a nice warmth or edge. In the recording studio there are prized tube devices that are used because of their sound. Anything from tube based microphone amps to devices like a LA-2 or Fairchild 670. Reproductions of these are still made, and are a steal compared to a real vintage device, if you can find one.
You can get a tube warmth with little more than a single tube and an appropriate circuit - a simple cathode follower to get just a weeny bit of colour. But the idea of using a tube based amp in a car is just plain silly. I suspect any commercial car system will only have a single tube used like this.
I’ve been out of semi-pro audio for 30+ years. ISTM that nowadays it ought to be trivial to map the actual transfer function of actual tubes and tube-based amps. And to DSP that into any signal you want.
So it ought to be practical to have digital-domain amps with various settings to mimic the sound of any well-studied amp in history to any desired degree of fidelity.
Are there such in production today?
I don’t know about finished products, but yes it should be trivial. An Analog Devices SigmaDSP like the ADAU1701 could easily do it within its 50 MIPS budget, and they cost like $5 in quantity. Even a pretty powerful floating-point SHARC is less than $10.
actually now that I think about it, I believe a lot of guitar effects boxes do just this to simulate the “Tube sound.”