Home > Amp Parts
> THD Yellow Jacket EL84 Tube Converter
> THD YJSQ Yellow Jackets
Product Categories: THD Yellow Jacket EL84 Tube Converter
THD YJSQ Yellow Jackets
click image to enlarge
Quantity in Cart:
Temporarily out of Stock.
THD YJSQ Yellow Jackets
YJSQ Yellow Jacket Quartet for 6V6, 6L6, EL34 Tube Replacement (Tubes included)
What are Yellow JacketsŪ?
Yellow JacketsŪ Converters are a type of specialized adapters which permit the use of EL84/6BQ5 power tubes in place of 6V6, 6L6, EL34, and 7591 types.
How do they work?
They give you simple Class-A operation from any amp.Yellow JacketŪ 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, while configuring the EL84 in a Class-A, Self-adjusiting cathode-bias circuit. In other words, there are no adjustments to make and no modifications necesary, you simply plug the Yellow JacketsŪ into the amp's output tube sockets, (in cathode-bias amplifiers) screw the ground wires under one of the output tube socket mounting screws, plug the provided EL84's into the Yellow JacketsŪ, turn on the amp and play.
How will they change my amplifier?
It's like getting a whole new amplifier! In Champ and Deluxe type amplifiers, the Yellow JacketsŪ output is smooth, strong and more even than with the stock 6V6s. When the Yellow jacketsŪ Converters are installed inlarger 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 JacketsŪ are used in a Marshall 50 watt or similar amplifier, the overall power drops to about 20 watts 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 JacketsŪ. In a 100 watt amp like a Twin Reverb or Marshall 100, either two or four Yellow JacketsŪ can be used. If only two are used and the other two sockets are left empy, the output is dropped to about 20 watts. With four in place, the amp puts out about 40 watts and takes on a whole new warmth and richness.
In the cases of the YJ7591 converters, the overall ouput power remains the same, but the sound becomes fuller and the extinct 7591 are replaced with common and inexpensive EL84 tubes. In old Ampeg Reverb Rockets and the like, you experience a warmth and sweetness that you could never get with the now unavailable 7591 tubes.
Will they hurt my amp?
No! Yellow JacketŪ converters are safe for all amplifiers and transformers. As all Yellow JacketŪ Converters internally limit voltage and current they put no extra strain on amplifiers' power and output transformers or internal components. Using the Yellow JacketsŪ in higher powered amplifiers actually reduces the strain on the transformers and internal components because it reduces the overall wattage of the system. Furthermore, the heater (or filament) current of the EL84 is lower than that of the 6L6, EL34 or 7591, so the Yellow JacketŪ will reduce the strain on the filament windings of the power transformer as well.
THD YJUNI Yellow Jacket For UniValve or BiValve Single Tube
THD YJUNITriode Yellow Jacket Same as above in Triode version for even less output.
THD YJBIV Yellow Jackets For UniValve or BiValve Duet
THD YJBIVTriode Yellow Jacket Same as above in Triode version for even less output.
THD YJ20S Yellow Jacket For Single 6V6 Tube
THD YJ20STriode Same as above in Triode version for even less output.
THD YJ20D Yellow Jackets For 6V6 Duet
THD YJ20DTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJS Yellow Jacket For Single 6V6, 6L6, EL34
THD YJSTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJSD Yellow Jacket For 6V6, 6L6, EL34 Duet
THD YJSDTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJSQ Yellow Jackets For 6V6, 6L6, EL34 Quartet
THD YJSQTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJC Yellow Jacket For Cathode Bias Amplifiers Single
THD YJCTriode Yellow jacket Same as above in Triode version for even less output.
THD YJCD Yellow Jackets For Cathode Bias Amplifiers Duet
THD YJCDTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJSHORTD Yellow Jackets For 6V6, 6L6, EL34 Duet (Short Version where space is a concern)
THD YJSHTDTriode Yellow Jackets Same as above in Triode version for even less output.
THD YJ7591D Yellow Jackets For 7591 Duet