Amplifiers have contrasting stages being them voltage amplification, preamp section, power stage, and output stage among others.
Although every component takes place in the whole result, today we will be focusing on the preamp and power tubes, found in their corresponding sections.
Both stages involve glass valves presented in every tube amp but how different are they? Is one of them more important than the another?
Which is more relevant in modeling tone? And which one regarding the volume? This may seem like a lot of confusing information but let me explain it.
In short, power tubes could be thought of as more influential than preamp valves, since when cranked they add a lot of harmonics that color the tone. Preamp tubes have a more functional use and don’t determine that much of the amp’s tone.
In this article, I will try to evacuate every doubt that could come up about this issue.
Afterward, you will know everything about this topic so continue reading until the end and you will become an expert!
What do preamp tubes do on an amp?
Preamp tubes are small glass tubes located in the back part of every valve amp, they are easily recognized because are the tiniest tubes.
What they do is pre-amplifying the signal before it is sent to the power stage section, they pick up and convert the signal level to line level.
Another remarkable aspect regarding preamp tubes is that they raise importance in shaping the tone of your guitar.
Although they do not have as influence as power tubes, they can model and distort the signal as well.
What do power tubes do on an amp?
Contrary to the preamp, power tubes are bigger valves also placed at the back end of the equipment, they come in different sizes and shapes, resulting in various diverse outcomes depending on the type of power tube used.
In the same way preamp valves do, power tubes take an important role not only in shaping the tone but also in amplifying the signal.
The interesting feature of power tube’s performance is how they frame the sound through the natural distortion which occurs when cranked.
This is a characteristic relegated to power valves, as explained before, preamp tubes also produce overdriven sounds but the distortion provided by power tubes is stronger, more noticeable and the one that defines the amp’s outcome.
Which are more influential on tone preamp tubes or power amp tubes?
The resulting sound of an amp is not determined just by a single piece or component, that’s why it is said that the overall sound of any valve equipment is defined by both, preamp and power tubes.
However, it is also true that power tubes may be more dominant when shaping the tone, as there aren’t several preamp tubes, most amps tend to use the same or similar ones, therefore power tubes gain importance in this area.
Although some power valves are alike in terms of sound, we can find a wide and vast range of different tubes which vary their tone.
What is more, they change from amp to amp and from model to model, for instance, Marshall equipment uses EL34 tubes which defined the popular British sound.
Oppositely, Fender Company (and more other American brands) employed 6L6 tubes in the construction of their amps, defining the tone of most American bands.
As you may notice, different power tubes provide dissimilar results plus the overdriven tone it varies depending on the tube used, that’s why we can assert that power valves are more influential on tone.
Do both stages of an amp sound better at high volumes?
As a matter of fact, is well-known that tube amps reach their more glorious spot when turning up the volume, we already said that both stages are involved in the general performance of any gear but regarding this topic, power tubes are the ones who really take profit from high volumes.
In the case of the preamp section, their job is to pre-amplify and model the signal so, even though they take part in the equipment function, the amount of volume doesn’t mind that much, in fact, they don’t change their performance at different volumes.
Power tubes instead are intended to show their real capabilities when cranked, up to that point they truly shine, and they produce a natural overdriven signal which is very musical, nice-sounding to the ears, and in short, what actually defines a power tube’s sound.
Why are there fewer alternatives for preamp tubes?
Within both, power and preamp tubes we can find different alternatives, nevertheless, when paying attention to preamp ones we may notice that there aren’t as many options as power tubes.
This might be due to preamp tubes are not as influential in tone as the power stage, thus less amount of choices.
Having mentioned that, I would like to say that various preamp tubes connected through a gain chain can result in a louder output but they are pretty similar to each other.
In addition, the more preamp valves your amplifier has, the more tonal options it provides but again tubes are very similar and quite finite, that’s why there is a limited number of options.
Would you notice a difference in tone between power tubes at low volumes?
Contrary to the preamp stage, the power section has a broad, extensive amount of options that can make your amplifier sound extremely different depending on the one you are using.
When discussing which tube gains more influence on the tone we stated that power valves do but it always depends on the amp’s settings.
What I mean to say is that you will see the real tube’s job when they are cranked and pushed to the limit, you can do that by turning the volume up.
Otherwise, power tubes won’t be so different, they show their real potential at high volumes, therefore, there’s no point in playing at low volumes, you won’t notice many tonal differences from each other.
Although it is already said, this topic deserves a further explanation, if you still feel curious about it I will suggest you take a look at one of the articles on the website which clarifies everything you need to know about this issue.
I will leave you the link to it below!
Needless to say, when talking about amplifier outcome every component influences the equipment, not only preamp or power tubes but also the rest of the presented sections.
In short, preamp tubes are more related to volume whereas power valves have more to do with shaping tone.
Moreover, their performance regarding tone is really hard to fully explain just in an article so, I encourage you to check out some articles we offer for each of them.
The links will be just right below, hope you enjoy them.
Hello there, my name is Ramiro and I’ve been playing guitar for almost 20 years. I’m obsessed with everything gear-related and I thought it might be worth sharing it. From guitars, pedals, amps, and synths to studio gear and production tips, I hope you find what I post here useful, and I’ll try my best to keep it entertaining also.