ECC81 - ECC82 - ECC83 - ECC88 and some more

There has been designed a series of universal dual triodes with Noval base, in the 1950's. This family has ca. 40...60 members, but many of those had no HiFi purpose, or were unlogical developments. Today ECC81 - ECC82 - ECC86 - ECC88 are the most popuar of those. All good things are not possible to get simultaniously in one tube. So high gain and low output impedeance, and low noise, and and..... can not be designed into one tube, unless you invest in very high heater power, and large size of the tube. A nice example for this is the change from ECC82 to 6CG7, where 6CG7 may seem the better tube. However 6CG7 uses more heater power, and needs more plate dissipation.

WIth this table, you may also understand why in some applications two tubes are in parallell, this will keep everything unchanged, but will lower the output impedance to half the value. So two systems of EC82 in parallel give a better driver than one triode of the 12BH7.

You need to select the tube for what you want to do with it in the first place. So if you design a circuit with high gain, and low output impedance you need one tube for the gain, followed by a one for the low output impedance. The high gain tube, you don't care about the impedance, and the low impedance tube you don't care about the gain.

The intention of this page is not to describe all applications, and differences in detail. The purpose here, is just to make quickly clear what kind each tube is BEST suited for. Of course they can be used another way, and millions of good and bad circuits were designed. Use this table to understand quickly what the tubes are suited (and not suited) for.