Generally 6V6 valves are robust and can be used above their specifications (the 6P6S, which has a lower tolerance, is an exception). Thanks to this, 6V6 are very popular in tube audio amplifiers. This market allows that they continue to be manufactured today. It is also widely used in guitar amplifiers, such as the Fender Champ.
Sounding 6v6 tubes
The 6V6 valve is a beam-power tetrode vacuum tube introduced by RCA in 1937, which is still used in some applications. Similar to its predecessor, the 6L6, the 6V6 was much more used. While the 6L6 was an excellent valve, it was not suitable to be used in domestic appliances of the time because it required a large amount of energy and therefore a large, hot and expensive power source and generated more sound power than that required, especially in a push-pull circuit.
The 6V6 is most commonly used in the amplifiers. The popular vacuum tubes are also the EL34, KT88 and 300b. Each of these is different in terms of power, construction and sound.
In some of the best amplifiers the most resistant valves in the world are used: the Russian ones. The duration is 10,000 hours, which become about 9 years, assuming a listening time of 3 hours a day, every day, and 365 days a year. The number specified by the manufacturer, for example 10000 hours, does not necessarily mean that the pipe breaks after this time. This is only a guarantee regarding the tube emission parameters. After the elapsed time, the amplifier could, but not necessarily, lose a minimum fraction of its rated power, for example falling from 35W to 30W. Of course it will continue to work normally.
Electro Harmonix 6V6 Single Valve
The new 6V6 Electro Harmonix combines a newly developed cathode coating, better alignment of the grids and the plate with a coating in a particular alloy, which as a result gives us a very robust 6V6 with a wonderful sound and able to easily withstand anodic tensions up at 475V.
The sound of a tube amplifier is rich in heat, dynamic, but above all, it is very natural. If this kind of result is what you are looking for, buying a vacuum tube-based amplifier will be the best decision. In the most common transistor amplifiers there are often numerous circuits that modify the sound, such as “loudness”, the equalization for the high or low tones, so as to make their timbre warmer a bit harsh, cold and cutting. But we must bear in mind that such a modified tonality is not and will never be natural. It is only by using this type of precautions that such equipment can somehow return the heat that is intrinsic to valve devices.
Michael from Liverpool writes: I bought it to improve the sound of a small VHT brand amp, and it has actually improved considerably. The reason for choosing this valve is that reading in forums and talking to some friends who know the subject, I was recommended to adapt better to the voltages of power transformers of dubious quality. I do not know if what I have just said has coherence, but it is the only thing that I more or less understood. The amp has gained clarity; it has sharper and sharper bass and without getting dirty has become thicker and stronger.
JJ Electronics Amplifier Tube
Octal power tube is as solid as a rock capable of holding large voltages. With the JJ 6V6-S you will never have to look for more NOS valves, because it is designed like the old ones and even improved giving a sound from Blues to Rock with spectacular results that makes it one of the best 6V6 in the market by far. It is sold tested so that your amplifier gives you the best sound and performance possible.
The NOS (“New Old Stock” tubes) are those that were produced many years ago, often stored in their original packaging and until now have not been used. NOS tubes should only be purchased from verified sources, with their previously measured parameters, and then sorted by selected pairs or quartets. Often, due to collectors, their prices may be even higher than similar ones in current production. Definitely worth trying, listening to them to find out how they sound in your amp.
Tung-Sol 6V6GT Vacuum Tube
This 6V6GT is the favorites of many musicians and technicians in the world to equip Fender Tweed Champ and Deluxe amplifiers. This model holds very well the high voltages and has used the best existing materials to recreate the classic 6V6 of all life.
David from Tel Aviv writes: “I bought this valve made in Russia to replace the one I had in stock (a Ruby made in China) of my RANDALL RD5 combo and the result is very positive. It has endowed the sound of the amplifier of greater headroom, more harmonics, more balanced means and treble and powerful bass. Even though I use the amplifier to make metal and I doubted that this valve was not suitable for this type of styles, it has surprised me very pleasantly since it has enough stuck and makes the cone work very well.[/quote]
I also took the opportunity to change the pre-valves (which were also Ruby) to higher-grade ones (a Boogie SPAX Table in the V1 position and a Groove Tubes Phase Inverter in the V2 position) and now the amp sounds much better, with more gain, more sustain, more harmonics and more defined.
James from San Francisco writes: “I am very satisfied: good harmonics and excellent value for money. They are very clean. Try to buy them paired. With the orange they go pretty well. It is ideal for boutique amps with a vintage tone”.
Telefunken Elektroakustik 6V6-TK
If you are looking for a sound different from the standard, then this tube is a good option. The company is recognized for its products that are strong and consistent. Tubes are processed cryogenically to ensure maximum stability, are tested according to strict standards.
The Elektroakustik 6V6-TK is robust and can be used above its specifications is very popular in tube audio amplifiers. The maximum plate voltage supports 315v declared with 5.5W of output power.
The importance of Bias
The Bias is the “amount” of current that passes through the filament of the final valves when they are at rest. Each valve works well with a certain amount of current so that the good operation and the sound performance of the tube amplifiers depend a lot on this regulation. In practice, if the bias is too low the valve sounds “cold” and not very full-bodied. However, working below the critical values, the circuit does not run any risk and the valve itself is destined to last longer. It also increases the threshold beyond which the amp begins to distort.
If the Bias is too high, the valve sounds (and becomes) “very hot” and distorts more easily, but beyond certain limits it can happen that excessive heat is not dissipated and the valve burns out and goes into short circuit. In this unfortunate event there is a risk of burning also the power transformer and/ or the output transformer.