THD YELLOW JACKET® YJS CONVERTERS

• Converts most audio amplifiers with 6L6, EL34, 6550 or 6V6 tubes to  EL84/6BQ5 tubes without modification or rebiasing.

• Converts from Class-AB to Class-A operation.

• Drops output power by 50% to 70%.

• Safe for all common amplifiers and transformers.

• EL84/6BQ5 tube not included but is available from Radio Daze.

INSTALLATION
1. With your amplifier cold and turned off, remove the 6V6, 6L6 or 6550 tubes from their sockets. (Use a towel to protect your hands if the tubes are hot.)

2) Place the Yellow Jacket Converter in the tube sockets and install an EL84 tube into the Yellow Jacket.  Make sure that all pins are properly aligned and do not force anything.  It should all go smoothly if the tubes are properly aligned.

3) Turn the amp on, let it warm up, and play. Your amp is now running in Class-A mode with and EL84 output tube.

You do not have to adjust the bias of your amplifier as the Yellow Jackets themselves create their own cathode bias circuit, ignoring the bias settings in your amp.  This also means that when you put your old tubes back into your amplifier, your bias will be set just as you left it.

Yellow Jackets are not to be used in amplifiers with extremely high plate voltages such as Marshall Majors, Ampeg SVTs, Hi-Watt 200's and Orange 120's.  These amplifiers have too high a plate voltage and will damage the EL84's and possibly the Yellow Jackets themselves.  While the Yellow Jacket reduces the plate and screen voltages each by 100 volts, this would make the plate voltage too high in certain amplifiers.

If you are not sure if the YJS Yellow Jackets will work in your amp, please feel free to contact the factory either by phone or by e-mail.  They will be happy to advise you on your individual situation.

Amplifiers which vary the bias voltage to create tremolo effect will not have any tremolo effect when using Yellow Jackets.  This includes the Fender Vibro-Champ, Brown Deluxe Amp (6G3), Princeton, Tremolux (5G9, 6G9), and Vibrolux (5F11, 6G11) to name a few.

Cathode-bias amplifiers such as Fender Tweed Deluxe, Champ, Vibro-Champ, Tweed Princeton, Tweed Pro (5C5, 5D5, 5E5), Tweed Super (5C4, 5D4), Tweed Tremolux (5E9), Tweed Twin (5C8, 5D8) etc. require a custom version of the Yellow Jacket (YJC) with a ground wire to attach to the chassis.

If your amp uses 6V6 output tubes and you do not want a reduction in power, you need the YJ20 Yellow Jacket. If your amp uses 7591 tubes, you should use the YJ7591 Yellow Jacket.  The correct unit can be obtained from the factory or Radio Daze.  For unit exchanges, please contact the THD factory.