What
are Yellow Jackets™?
Yellow Jackets™ 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
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, 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 Jackets™ 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 Jackets™, 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 Jackets™
output is smooth, strong and more even than with the stock
6V6s. When the Yellow jackets™ 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 Jackets™ 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 Jackets™. In a 100 watt
amp like a Twin Reverb or Marshall 100, either two or four
Yellow Jackets™ 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.
Are
they a permanent modification?
No adjustments or modifications necessary, you can change
at will! As
the Yellow Jackets™ ignore the amplifiers grid bias voltage,
it is possible to take them in and out at will to adjust your
power level and sound for the individual gig or session. For
an interesting blend of sounds, you can even exchange two
of the output tubes in a four tube amp for Yellow Jacket™
Converters and leave the other two as 6L6s or EL34s. This
blends the sound of both and lets you run a combination of
Class-A and Class-AB.
Will
they hurt my amp?
No! Yellow Jacket™ converters are safe for all amplifiers
and transformers. As
all Yellow Jacket™ Converters internally limit voltage
and current they put no extra strain on amplifiers' power
and output transformers or internal components. Using the
Yellow Jackets™ 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 Jacket™
will reduce the strain on the filament windings of the power
transformer as well.
