vacuum tubes vs. transistors

Comparison: Vacuum Tubes Vs. Transistors – Noisylabs

Vacuum tubes can be used as an amplifier or switch. Remember, when we explained (briefly) direct current and alternating current in our post on "how to keep amp from overheating?"? 

Well, vacuum tubes also play a role when it comes to direct current and alternating current.

Vacuum tubes have electrodes which controls the flow of electrons.

On the other hand, you have transistors which can also be used as a switch or amplifier.

One big difference between the two is vacuum tubes are made out of glass while transistors are made out of silicon.

The debate here is finding out which one you should use.


Vacuum Tube's Pros

If you read the beginning, you'd correctly assume transistors are used more than vacuum tubes because there are more smaller devices.

But there are instances where vacuum tubes are used.

If you're an owner of a high-voltage audio system, a vacuum tube is a good idea.

If your sound system projects to have a higher frequency of 10 GHz, then a vacuum tube is for you.

The higher the wattage to kilowatt ratio is, the more likely it is you need a vacuum tube.

Another pro of vacuum tubes is its durability.

Durability is a big factor whenever we're talking about outdoor speakers and Bluetooth speakers.

And vacuum tubes are an asset when it comes to durability.

Their material is composed of glass, ceramic insulators, and metal electrodes. Insulating materials get stiffer when compressed, but that doesn't mean you can sit on your devices.

There's a lot of stress electronic devices go through. Durability doesn't just include weather and small particles.

Another component to its durability is a tube's ability to handle current and temperature surges.

Vacuum tubes are meant to handle high voltages. And if a device can handle high voltages, that means it can handle a lot of heat.


Vacuum Tube's Cons

An obvious con are vacuum tubes are bulky. This makes your circuit board less efficient. The more amps/switches you can place in an audio system, electrons will flow better.

As we've mentioned, vacuum tubes can handle high voltages. But high power consumption means you'll need a heater supply.

Heater supply means lower efficiency and wasted heat. But that's not the only disadvantage.

Electronic devices have a tendency to turn mechanical vibrations into unwanted noise. This is what we call microphonics. And vacuum tubes are more probable to pick up microphonics than transistors.

Another disadvantage are vacuum tubes can also cost more than transistors.


Transistor's Pros

To make the complex simple, transistors are used more because they're easy to switch on.

What makes them easier to turn on is its smaller size. That smaller size allows transistors to not need as much charge.

All of the new devices we use today are portable. Examples include Airpods, smart phones, and more.

There's no way vacuum tubes fit in those devices. Small transistors are in these devices. A smaller size also means less power consumption.

You ever wonder how some Bluetooth speakers last so long? Now you have a big part of the answer.

This is from Sciencing.com:

"Transistors can be designed to use very little power. Millions of them in a watch or calculator can run for years on a small battery."

Another big part of small transistors is it reduces the cost for consumers. It makes producing transistors scalable.

And, without going into too much detail, transistors are faster. This is one of the big reasons transistors are used prolifically. 


Transistor's Cons

Transistors are reliable for circuit boards. But there are multiple ways they can fail.

One way it can fail is by shorting out.

A transistor shorting out means it can't regulate current flow. Think of this like a nurse drawing blood from a patient, but the insertion is wobbly so blood sprays out. The nurse will get blood in the IV, but it won't keep control of all the blood coming out.

This happens when a big enough current melts a positive and negative junction.

vacuum tubes vs transistors

positive (red) and negative (black) junction


Another way transistors fail is a transistor being "open." A transistor being open means resistance becomes very high. Too much resistance means electrons can't flow freely.

Here are a couple examples of transistors being open.

One open is between a base and collector. The collector's voltage needs to go down while the base and emitter go up.

Another open is the supply voltage and emitter. 

One way to know if your transistor is bad is to test the resistance between the leg. Measure the resistance between base to collector, collector to base, and more.

Other times transistors come in faulty. This happens in a majority of brand new transistors. Users can usually tell within a couple hours of use whether a transistor is faulty or not.

If one of your audio systems has a transistor and you place it in an area with equipment which uses frequency, then there's a chance it could pick up radio frequency interference.

Another downfall is transistors can self-oscillate because of low voltage diode junctions and slew-rate effects. And slew rate is a measure of voltage over time.

The last disadvantage we'll mention on transistors is they're harder to maintain.

Also, they're probably harder to replace. Their designs are meant to perfectly fit circuit boards. A stock transistor has a high chance of not fitting in.


Winner?

Audiophiles prefer vacuum tubes because of the sound it emits.

There are a lot of reasons why a transistor or vacuum tube will be the right answer.

But our pick is transistors. The answer is obvious the more we think about it. Most, if not all electronic devices contain transistors. There must be a reason for that.

The 2 biggest reasons are because it provides efficiency and are easy to scale. Although its scalability is something consumers don't care about, efficiency is reason enough to go with transistors.

Efficiency makes it easier on power and sound. Your sound system doesn't have to work as hard to produce the same sound.

The winner here is transistors.

1 thought on “Comparison: Vacuum Tubes Vs. Transistors – Noisylabs”

Leave a Comment