6L6 | 5881 | KT66 | 7027 | 7581 | EL37

Shop our large selection of 6L6 & equivalent vacuum tubes. This is one of the most popular power tubes on the planet and as such, there are almost unlimited options. 

There is much confusion surrounding the equivalent and substitute tubes in regards to 6L6. Much of it has to do with the fact that the tube has been around for so long, it has been revised and new versions have been made. Please see our guide below:

6L6 (no suffix)

Typically only seen on the metal version. This is the earliest version of the 6L6 and is only rated at 19 watts vs 30 with the 6L6GC. Also, pin 1 is tried to ground meaning that these could become charged and dangerous on the wrong circuit. Best to only use if your amplifier calls for 6L6 with no suffix.

Direct equivalents / drop-in substitutes: 1614, 1622, 6L6Y, VT-115.

6L6G / 6L6GA

Like the metal 6L6, these tubes are rated for lower wattage than the 6L6GC. These are always glass and ST shaped tubes and are the earliest glass 6L6s. The 6L6G is very large and bulbous where as the 6L6GA is a bit smaller but that is the only difference between the two so they are directly interchangeable. 

Direct equivalents / drop-in substitutes: 6L6G, 6L6GA, VT-115A, CV1947

6L6GB / 5881

The 5881 is the standard for guitar amplifiers that wanted to be rated at slightly lower watts than amps with the 6L6GC. While the 6L6GB can handle 23 watts and 5881 can handle 26 watts, they are interchangeable in almost every scenario. The 6L6WGB is identical to the 5881 and of course is also interchangeable. 

Equivalents & Substitutes: 6L6GB, 5881, 6P3S-E (Russian)


The 6L6GC is the tube that changed everything. While the earlier versions of 6L6 were great sounding and robust, they lacked power. The 6L6GC puts out a full 30 watts and does so in a cleaner and more linear way than most power tubes. A 6L6GC can be used in place of any other 6L6 but not the other way around. 

Equivalents & Substitutes: The KT66 and 7581 are the only drop-in substitutes for the 6L6GC and even so, they are significantly different and will require re-biasing. The Russian 6P3S but NOT the 6P3S-E is a drop-in substitute for 6L6GC although they can handle 25 less volts on the plate so they may not last as long.