A beam power tube, also known as a beam tetrode, refers to a type or kind of thermionic valve or vacuum tube. It divides the electron stream coming from the cathode into several partially collimated beams and comes with two grids.
In addition, it creates a space charge region having a low potential between the screen grid and the anode.
You may have heard of a few famous beam power tubes such as 6L6 and 5881 and the debate between 5881 vs 6L6.
The two have a few similarities and differences, which we will discuss in this article. Before that, let us look into its primary purpose.
A beam power tube, be it 6L6 or 5881, returns the electrons from the anode secondary emissions to the anode.
It does so when the potential of the mentioned component becomes less than the equivalent or same value of the screen grid. Thus, a beam power tube aids in power amplification, enhancing it from audio to radio frequency.
Thus, a beam power tube can generate superior output power compared to a pentode or triode with the same supply voltage to the anode.
5881 vs 6L6 Tubes: Which is Better?
When speaking about 5881 and 6L6 tubes, you can say they belong to the same family. It is evident once you review the two options. However, it does not imply that the two are the same in all aspects with no differences.
Instead, 5881 and 6L6 tubes differ on a few specific points and factors. It gives rise to the comparison between them, making you think which one is the better option.
Let us first delve into and deliberate on the distinctions between the two before concluding the question’s answer.
Firstly, 5881 tubes have lower power than the 6L6 tubes. In other words, the former is a 23W valve while the latter is a 30W valve. It means that you will find less headroom if your choice lies with a 5881 tube.
On the other hand, a 6L6 tube will provide you with a cleaner headroom and more power.
Hence, you should not choose this one if you desire a power tube breakup. Thus, it serves as a significant point of distinction that can influence your choice.
Next, the additional 5W you can get per tube of 6L6 will allow you to drive a bass better. Moreover, you will get to run it clean. However, you should go with a 5881 tube if you want distortion.
Additionally, 5881 tubes cannot withstand high plate voltages. It is due to their smaller plates. Such issues do not occur in 6L6 tubes.
Thus, the answer to which one is better- 5881 or 6L6 tubes will depend on the aspects and elements you desire. For instance, you can say the latter is the superior choice if you want high output power and no distortion.
Are 5881 and 6L6 The Same?
As stated before, the 6L6 and 5881 tubes fall under the same family and category of valves. Thus, they are similar and not identical. It implies there are no 5881 tubes that are the same as the 6L6 tubes and vice versa.
Firstly, the 6L6 tubes were the first beam power tube to experience a successful market launch.
Later, other variants came into the picture, getting manufactured and utilized in high-fidelity musical instrument amplifiers and audio amplifiers.
For instance, the versions of the 6L6 tubes consisted of 6L6G, 6L6GB, 6L6GA, and the most recent 6L6GC.
On the other hand, the 5881 tubes are beam power pentodes. They have a plate dissipation at a maximum of 23W. It is so when you consider a classical short bulb.
The 5881 tubes are exceedingly similar to the 6L6 tubes. However, they have less power. Nevertheless, they can get utilized in any 6L6 amplifier.
You can say that the 5881 tubes serve as a 6L6 or 6L6GC equivalent, as mentioned in the 5881 datasheet. However, the screen values and dissipation remain increased by about 20%.
It means that the design of a 5881 tube will allow it to handle and resist vibrations and shocks better than 6L6 tubes.
On top of that, the application of treated anode and grids in the 5881 tubes improves their overload capacity. It, in turn, increased its longevity. So, you will be able to use it for a significant time.
In addition, the 5881 tube possesses a squat tubular construction, unlike the 6L6 tubes. Furthermore, the cross box anode can obscure or block the other electrodes.
Nevertheless, you will find that the system allows for a suitable and desirable level or extent of heat dissipation.
Next, you will get the 6L6WGC and the 6L6WGB tubes as a 5881 tube equivalent.
Moreover, you can say that the Tung-Sol 5881 falls under the category of the best 5881 power tubes. It is a sensation product and one of the most superior products in its range and type.
Can I Replace 6L6 With 5881?
Before we begin with the answer to the question, let us first clarify and remember one essential thing. A 6L6 tube works on 30W. On the other hand, a 5881 is fundamentally a 23W tube.
The disparity in the wattage plays a significant and crucial role when you replace the 6L6 tubes with a 5881. For instance, the former has a lower tolerance or resistance to high plate voltages.
Thus, it will create scenarios where you can successfully replace a 6L6 for a 5881 tube but not the reverse case.
On top of that, you will be able to use a 5881 tube in amps designated or designed for the 6L6 tubes. It primarily happens when the plate voltage tolerance remains high enough.
However, you will essentially or fundamentally be downgrading the plate voltage and valve power rating if you do it.
The 5881 tubes are more rugged compared to the 6L6 tubes. On top of that, the former may break up faster or earlier if you put the 23W one in place of a 30W one.
It stands true when the other samples idle cold while the individual tube samples remain idle hot.
In other words, the 5881 tubes will run on a comparatively higher rail if they replace the 6L6 tubes. However, you will find that it cuts their lives short.
Another consequence of replacing a 6L6 with a 5881 tube is the issue or effect of distortion. The problem happens faster for the latter than for the former.
Nevertheless, you can go forward with the replacement if you wish to get a “dirtier” or “grittier” sound.
Thus, strictly speaking, you can replace a 6L6 with a 5881 tube. However, you may get a few undesirable and unappreciated effects and consequences.
In addition, the decreased lifespan or longevity of the beam power tube may not play in your favor.
What is the Difference Between 6L6 and 5881?
As we had discussed before, 6L6 tubes and 5881 tubes have a few differences between them. It may be on the parameter or basis of their construction, wattage, application, effect, etc.
For instance, you can compare the two beam power tubes under the headings of 5881 vs 6l6 sound or 5881 vs 6l6 tone.
Let us make a comparison table to understand the differences between 5881 and 6L6 tubes.
|Serial Number||Basis of Difference||6L6 Tube||5881 Tube|
|1.||Wattage||L6 tubes can work or operate on wattage of 30 watts.||The 5881 tubes can work or function on a wattage of 23 watts.|
|2.||Headroom||6L6 tubes provide more headroom. In addition to that, they are cleaner.||The 5881 tubes provide comparatively less headroom.|
|3.||Plate Voltage||6L6 tubes can withstand and work with relatively high plate voltages.||The 5881 tubes can withstand and work appropriately when the plate voltages are high.|
|4.||Sound||A 6L6 tube can help you make a full-bodied and warm tone generally well-suited for the country, blues, metal, or rock. It can get owed to its more present midrange and higher headroom. It allows for a “full” yet versatile sound.||A 5881 tube can help you make a more distorted sound. It allows for a warm and rich tone well-suited for jazz, R & B, fusion, or blues. It can be because of its deep bass, tapered highs, and articulate mids.|
|5.||Mechanical Ruggedization||6L6 tubes are not ruggedized if you compare them to the 5881 tubes.||The 5881 tubes are ruggedized if you compare them to the 6L6 tubes.|
|6.||Gain||6L6 tubes have a comparatively lower “gain.” On top of that, you will not find them breaking up easily.||The 5881 tubes have a comparatively higher “gain,” though the value is exceedingly low. Thus, you may find them breaking up easily.|
|7.||Power Output Capabilities||6L6 tubes have comparatively more or higher power output capabilities.||The 5881 tubes have comparatively less or lower power output capabilities.|
|8.||Power Dissipation||6L6 tubes have a comparatively higher power dissipation. They have specific ratings for the mentioned parameter for the combined screen and plate and only the screen. The value for them stands at 24 watts and 3.5 watts, respectively.||The 5881 tubes have a comparatively lower power dissipation. The value stands at 23 watts. In addition, the second grid power dissipation has a rating of 3 watts.|
How Long Do the 6L6 Tubes and the 5881 Tubes Last and When to Replace Them?
The longevity of the 6L6 tubes and the 5881 tubes is a relative term. It signifies that they will last for an extended period if you do not use or utilize them minimally.
However, they might end their lifespan considerably faster if you use them extensively, such as almost daily.
On average, the two beam power tubes have a specific lifespan. For instance, the 6L6 tubes can last for approximately six to twelve months.
On the other hand, the NOS 5881 tubes, such as the OS Tung-Sol 5881, can stay in operation for almost 10,000 hours while functioning with a plate voltage of 450 volts.
Generally, you will notice that beam power tubes keep wearing out primarily by the sheer number of hours they get used.
On top of that, the values of how hard you work on them and allow them to heat up from the box heat play substantial roles in determining longevity.
In addition, thermal shock, or the number of times the tubes get switched off and on, is a significant factor.
For instance, suppose you play a beam power tube at maximum warp and into a dummy load such as an attenuator or power brake. In such cases, it gets considered that you have been playing it “hard.”
Then, you may think the tube has ceased operation or undergone malfunction because you will not be able to hear any sound.
So, fundamentally speaking, your ears will guide you when to replace the beam power tube. You should change them when they do not sound as sweet or pack a punch.
How Does a 6L6 Tube Differ From EL34?
On a comparative basis, the EL34 provides more distortion than a 6L6 tube. It implies that you will have a softer breakup and clipping. On top of that, EL34 comes with less headroom.
On the other hand, 6L6 tubes have more headroom. In addition, you will find a more abrupt and harsher clip. Nevertheless, you will get a cleaner tone or sound.
Another essential factor is that the 6L6 tubes will have less sensitivity towards the input grids than an EL34. Thus, it will allow you to make or produce a more pleasant or improved sound.
How Does a 6L6 Tube Differ From 6V6?
A 6L6 tube will help you get and produce a smooth and clean sound. However, it comes with a low sensitivity level and a somewhat harsher tone due to its “abrupt” clip. Nonetheless, you may find it appealing for some purposes.
On the other hand, a 6V6 helps generate a warm tone. In addition, it provides comparatively less headroom than the 6L6. Moreover, a 6V6 creates a tighter bass sound.