Voltage regulators and line conditioners are used in front of our commercial grade tube testers and our tubes are tested twice on two different testers for accurate and consistent results. Our matched tubes are always identical and we prioritize matching current because current is the most important factor when matching power tubes. Then by Dynamic Mutual Conductance (Gm), the amount of use if any, and finally by logos and manufactured date. We also bias all of our power tubes as sets in one or more of our amps to insure they look and perform well together.

Our test results are provided as a courtesy to help guide you in determining the best product for your needs. We do not warrant that our tubes will test the same or perform in any specific manner when used and/or tested in your equipment. No one can truthfully warrant this because of the variations in line voltage, interaction with other tubes and components, different bias schemes and circuits, etc. We do warrant that our tubes produced the results given in each description when tested by us in our equipment and will perform satisfactorily in your equipment as intended by the original manufacturer. No other warranty is given or implied.