Though designed to do the same thing, tube and solid-state headphone amplifiers (amps) differ in a number of ways, ranging from design to functionality. The solid-state amplifiers for headphones use a range of electronic transistors to drive their amplification. Tube amplifiers, on the other hand, use vacuum tubes or thermionic valves to amplify the input sound signal.
Theoretically speaking, both solid-state and tube amplifiers are designed to yield similar results, with regards to output sound quality. However, this is not the case in real life. In this regard, the leading solid-state headphones are known to give out an accurate sound with minimal or no coloration at all.
On the contrary, Tube headphone amps are known to introduce a considerable amount of distortion—which may be perceived as added warmth. Get to know how the two headphone amplifiers compare and contrast to each other throughout this guide.
Tube headphone amps are relatively modular units, hence can have varying effects on the input signal. As opposed to this, the design of solid-state headphone amplifiers allows for reduced coloration, which results in amore accurate sound. When pushed to the limit, a solid-state amplifier will not distort sound pleasantly as a tube amplifier would.
As compared to tube amplifiers for headphones, solid-state amps differ significantly in terms of size/portability, output power, pricing and output sound quality. Either of the amp types may be used separately or as combos to suit different applications.
- 0.1 What are Tube Headphone Amplifiers?
- 0.2 What are Solid-State Headphone Amplifiers?
- 0.3 Solid-State Vs. Tube Headphone Amplifiers
- 1 Final Verdict
What are Tube Headphone Amplifiers?
Also referred to as Thermionic valves or Vacuum amps, tube amplifiers for headphones use vacuum tubes or valves to amplify the input signal. It is the oldest sound amplification technology that features controlled flow of current through a vacuum-sealed glass valve(s).
Although it is a rather old technology, tube headphone amplifiers the perfect blend of design, output quality and overall performance. These amps have been proven to offer a greater sense of ‘bloom’ as well as enhanced sound texture and realism for vocals, and musical instruments.
The leading tube headphone amp models will offer you a great value for you money (Watts per dollar), while allowing for faster sound delivery and greater detail. In their design, tube amps feature a power transformer and two output transformers—one for each channel.
Generally speaking, tube amps sound better as a result of their euphonic distortions, as well as a range of other benefits they have to offer. So, what exactly makes Tube headphone amplifiers stand out?
Even-Order Harmonic Distortions
As opposed to solid state amps, tube amplifiers produce considerably more distortion—most of which is second-order sound distortion. Second-harmonic distortion is essentially the same not, at an octave above. This effect is often referred to as Harmonic distortion.
The harmonic distortion produced by tube headphones increases as you increase the output volume, making it suited for musical performance. Again, the percentage of harmonic content produced by the headphones tends to drop as the notes decay.
In some of the leading tube amps, such as the Woo Audio WA7 Fireflies, the level of distortion of distortion increases directly with an increase in output volume level. This results in a progressive ‘dynamic’ sound distortion experience.
As such, tube amps incorporate sharper ‘attacks’ while retaining the long, floating ‘sustains’ for each musical note they produce. This is precisely why tube amplifiers sound great when played softly. In contrast, you need to turn solid-state amps volume up to improve sound quality.
Optimum Sound at Extreme Levels
Although tube amps do not give impressive lab results, their distortion results in a great sound quality that sounds good at almost any volume you play it. With solid-state headphone amplifiers, you can only get the best performance and sound quality towards the maximum output level.
As you may be aware, solid-state amps sound their worst when played at low output levels. This is not the case with tube headphone amplifiers—these will give a great output quality at almost any output level.
Owing to their design, most tube amps tend to overload gradually—they distort more with increased input. However, these headphone amplifiers do not have a particular point (either above or below), at which they suddenly start to clip.
As opposed to this, almost all solid state amplifiers have a rather definite clipping point. When analyzed, the waveforms produced by tube amps end up clipping, but do not have sharp edges at any point. With solid-state amplifier waveforms, there is a sharp edge where the waveform clips (as if the waveform was snapped using a pair of scissors).
It is these sharp edges at the clipping that results in insane levels of very high order ultrasonic harmonics in solid-state headphone amps. As a matter of fact, this phenomenon is known to blow out tweeters connected to solid state amplifiers.
Maximum Power Output
Regardless of the make and model, tube power amps are normally rated for their power output capacity, often ranging between 8 and 80 Watts per channel (WPC). This is actually the range you need and are likely to be using for most amplifier applications.
Some solid-state amps can be rated as high as 300 WPC, which is too high for normal applications. While these will sound better at high output levels, they sound bad at the rational levels.
Zero DC Offset
Almost all solid-state amps have a negligible amount of residual direct-current (DC) voltage at the output. This is the case for even the older solid state amps that feature a single supply and large electrolytic output coupling capacitors.
Under the normal condition, the DC offset is rather low—often less than 10 mV. However, even the slightest of DC offset has been proven to displace the woofer cone slightly. Depending on the application, this may, in turn, result in added speaker distortion.
Well, this does not happen on tube headphone amplifiers. By design, tube amps are transformer-coupled. As such, they produce zero DC offset—a fact that is backed by lab test results.
High Output Impedances
Another good thing about tube amplifiers is the fact that they have comparatively higher output source impedances—often referred to as lower damping factors. This may be attributed to the output transformers and negative feedback of the amplifiers.
The leading models have a 1Ω output source impedance (which translates to a damping factor of about 8). Solid-state amplifiers, on the other hand, have near-zero output source impedances, especially for damping factors higher than the speaker connecting wires.
This is not a particularly good or bad thing, but the reduced damping factor in tube amps alters the transient response and frequency of the system. It results in reduced low-frequency damping, hence appears to bloom the bass.
Entirely Isolated Outputs
Some of the leading tube amplifiers, such as the McIntosh, feature a separate feedback winding, which isolates the output taps from other amplifier components. Since this can drive almost any load impedance, you can connect the output in series or parallel for enhanced mono experience or increased power output.
For instance, the MC225 and MC275 amps can safely power any 2Ω, 4Ω, 8Ω, 16Ω or 32Ω loads in mono. Such amplifiers also have exceptionally-high impedance outputs—150Ω to 600Ω in stereo, and even higher in mono.
This being the case, you will not need to worry about ground loops or interference, regardless of how you wire the outputs. In solid-state amplifiers, the outputs are not isolated. As such the mono options on stereo solid-state amplifiers are often bridge connections, which tends to lower their performance.
Tube Headphone Amp Pros
- Tube amps are inherently more powerful than any solid-state headphone amps
- Tubes add a bit of warmth, which can correct the output in bright sounding headphones
- Their design features glowing filaments that many find aesthetically appealing
- Sounds great at almost any output volume level
- Most tube headphone amps are known to reduce background noise considerably
Despite producing the best sound quality for most applications, the vacuum tube technology is very old, hence bound to have serious drawbacks. For instance, the older models may need to heat up for about 10 minutes before use.
Again, these amplifiers feature a bulkier design and are more susceptible to hearing problems.
What are Solid-State Headphone Amplifiers?
In their design, solid-state amplifiers feature transistor circuits that are used to convert electric current to audio output. Such headphone amps produce a clean tone and are quite versatile, allowing you to switch between different styles with ease.
This may be attributed to the emulation feature that is built-in to the amplifier. This makes them a great choice for users who love listening to a wide variety of music genres. As compared to tube headphone amps, solid-state amplifiers are comparatively cheaper, easier to maintain and portable.
However, they do not sound as good as the tube headphone amplifiers.
Solid-State Amp Pros
- They are comparatively affordable
- They produce accurate sound that is free of any form of coloration
- Deliver clearer audio and transparency
- Solid-state headphone amps feature a compact and lightweight design
The parts on a solid-state amplifier are harder to replace when faulty. Again, the sound quality produced by a solid-state amp at low volume levels is not impressive. You can only get great sound by cranking the volume up.
Solid-State Vs. Tube Headphone Amplifiers
A headphone amplifier is a low-powered audio device that is particular designed to amplify sound on headphones. Just as is the case with other amp types, headphone amps are available in two main types: tube and solid-state amplifiers.
Regardless of the type, headphone amps are often embedded within electronic devices that feature a headphone jack. They are commonly used on such devices as portable music players, integrated amplifiers and televisions. You can also get standalone headphone amps, especially for professional audio applications.
Solid-state amps differ from tube amps considerably, making them ideal for different applications. Discussed below is a detailed comparison between tube and solid-state headphone amplifiers:
While both are amplifiers and designed to do more or less the same thing, the sound produced by solid-state and tube headphone amps differs. With regards to output should quality, here is how the two headphone amplifier types compare:
Tube Headphone Amps
The leading tube headphone amplifier models are known to deliver a smooth, more responsive sound. This may be improved even further using high-gain pedals. Subtlety is another great quality of the tube amps, allowing for music to be produced at a more precise level.
Tube amps are considerably louder, hence a perfect choice for guitarists as illustrated below. With such an amplifier, you will also get a more natural and warmer audio output. The added warmth on these amps will come in handy if you have bright-sounding headphones—it will particularly tame the tremble peaks.
The vacuum tubes on these amps may be replaced with different types. This modular aspect of the amplifiers result in different sound effects. Despite all these benefits, tube amps increase the level of distortion—which may be a good or bad thing depending on the intended application.
Solid-State Headphone Amps
Well, some of the leading solid-state headphone amplifiers produce remarkably clean tones. Thy also feature built-in emulsion, allowing you to switch between different sound styles with ease. The output would quality produces by solid-state amplifiers—to a great extend—depends on the circuitry used on the amp.
While their sound quality cannot match the output sound quality produced by tube amps, solid-state amps have their benefits. They may sound inferior to you, but are actually suited for certain applications, as discussed later in this guide.
As you may be aware, solid-state amps and tube amps differ from each other in terms of construction, functionality, and output sound quality. As a result each of the headphone amplifier types is suited for a specific application, as follows:
As mentioned earlier in this guide, tube headphone amplifiers are considerably louder. This makes them ideal for use by guitarists in a band as they need to match up with the drummer’s sound volume. For such an application, a tube amp rated 50 Watts or more will suffice.
If you are looking for the maximum headroom (referring to clean, relatively loud, and undistorted audio output), a solid-state headphone amp would be a great choice. Due to the lack of distortion on their output signal, electric guitars will probably sound brittle when played through a solid-state amp.
Even so, these amplifiers are a preferred choice for keyboard players and bassists. It is also a great amp choice for Jazz players, especially the ones who play with minimal or no overdrive at all. In addition to the tonal benefits, such professionals love solid-state amps for their lightweight and compact design.
Voltage-driven Vs. Current-driven amps
The vacuum tubes used on tube headphone amplifiers are essentially voltage-controlled devices. In this regard, the voltage of the input signal is applied to the triode vacuum tube grid. This voltage is then used to regulate the output of the vacuum tube across its anode and cathode electrodes.
The dual bipolar junction and op amp transistors used in a conventional solid-state amplifier circuit are all current-controlled. Current flow from the base emitter is used to control a larger ‘amplified’ current across the collector emitter.
This being the case, we can conclude that the tube amp circuitry is voltage-controlled while the solid-state amp circuitry is current-controlled.
Owing to their varied designs and circuitry, tube amps sound a bit different from solid-state amplifiers. Holding other factors constant, tube headphone amps sound a lot better as compared to solid-state headphone amplifiers.
In this regard, tube amps will give out loud, smooth and more responsive sound with added warmth. These amps produce a considerable amount of distortion, which can be an added advantage in certain applications. Solid-state headphone amps, on the other hand will offer you enhanced versatility, and cleaner sound. Although they may sound inferior, solid-state headphone amplifiers are the perfect choice for piano players and bassists.