pucho812
Well-known member
anyone know what's inside products like the THD yellow jacket which converts your amps 6l6 power tubes into an amp with el84's looks to me like it it changes the pinout as well; as series resistors in key places..
here is a description
THD's Yellow Jacket converters not only rearrange the pin locations of the tubes, but also provide the necessary current limiting on the screens and cathode as well as blocking the amplifier's grid-bias voltage, configuring the EL84 in a Class-A, self-adjusting cathode-bias circuit.When the Yellow Jacket Converters are installed in larger amplifiers intended for 6L6s or EL34 output tubes, the high plate and screen voltages are reduced as well as current limited to protect the EL84 and to drop output power. When a pair of Yellow Jacket are used in a Marshall 50W or similar amplifier, the overall power drops to about 20W and takes on more of the character of an old Vox AC30. The distortion is smoother and more even and the output is both substantially reduced and more compressed due to the Class-A nature of the Yellow Jackets. In a 100W amp like a Twin Reverb or Marshall 100, either 2 or 4 Yellow Jackets can be used. If only 2 are used and the other 2 sockets are left empty, the output is dropped to about 20 watts. With 4 in place, the amp puts out about 40W and takes on a whole new warmth and richness.
here is a description
THD's Yellow Jacket converters not only rearrange the pin locations of the tubes, but also provide the necessary current limiting on the screens and cathode as well as blocking the amplifier's grid-bias voltage, configuring the EL84 in a Class-A, self-adjusting cathode-bias circuit.When the Yellow Jacket Converters are installed in larger amplifiers intended for 6L6s or EL34 output tubes, the high plate and screen voltages are reduced as well as current limited to protect the EL84 and to drop output power. When a pair of Yellow Jacket are used in a Marshall 50W or similar amplifier, the overall power drops to about 20W and takes on more of the character of an old Vox AC30. The distortion is smoother and more even and the output is both substantially reduced and more compressed due to the Class-A nature of the Yellow Jackets. In a 100W amp like a Twin Reverb or Marshall 100, either 2 or 4 Yellow Jackets can be used. If only 2 are used and the other 2 sockets are left empty, the output is dropped to about 20 watts. With 4 in place, the amp puts out about 40W and takes on a whole new warmth and richness.