Noval/9-pin tubes such as your typical 12AX7 or EL84 have pins that are mounted directly through the glass envelope. Since there’s no base assembly these tubes are indexed by aligning […]
#8. USA, European and Military preamp tube designations
Many tube types have a large number of common and not so common names that denote the same tube type/specs or similar specs with subtle changes or optimizations. The classic […]
#3. How Hot Should My Tubes Run?
Vacuum tubes found in common guitar amplifiers and most audio equipment can range from cool to the touch to several hundred degrees Fahrenheit. A typical 12AX7/ECC83 in a normal (low […]
#4. What Is Biasing?
In regard to basic tube amplifiers we can define “Biasing” as setting the idle plate current flowing through the tube. Less current means lower dissipation in the plate (less heat […]
#5. Does My Amp Need To Be Biased?
Generally speaking when we talk about biasing an amp we’re specifically referring to the output/power tubes. However there are some applications where specific pre amp stages may have adjustment or […]
#6. Is My Amplifier Class A? (Classes of Operation)
Very few guitar amplifiers are strict Class A. If you have a guitar amp with one power tube, which is known as single-ended, it’s Class A by default. This would […]
#7. Modes of Failure and Symptoms
Lost Vacuum: As the name implies vacuum tubes are built in such a way that the inside of the bottle (generally glass but in some vintage tubes can be metal), […]