INSTRUCTION SHEET
• Contains one Yellow Jacket converter model
YJShort
.
• Converts most amplifiers with 6L6s, EL34s, 6550s or
6V6s to EL84s with out mod i fi ca tion or re-biasing.
•
Converts from Class AB to Class A operation!
• Drops output power by 50% to 70%.
• Safe for all common amplifiers and trans form ers.
• Short enough to fit in most Backface Fender heads.
• One Year Limited Warranty on converters.
• “The next best thing to getting yourself a new amp.”
- Guitar World Magazine
• “Increase amplifier flexibility”
- Guitar Player Mag a zine
Thank You!
Thank you for buying our Yellow Jacket con vert er! It will
provide you with years of service, as sum ing that you re-
place the tubes when they are worn, and will also give
you a much greater variety of sounds from your am pli fi ers
than you have ever ex pe ri enced before.
How to Install the Yellow Jacket:
How to Install the Yellow Jacket:
1. With your amplifier cold and turned off, remove the 6V6,
6L6, EL34 or 6550 tube from its socket. (Use a towel to
pro tect your hands if the tubes are hot.)
2. Place the Yellow Jacket converter in the tube sock et
and in stall an EL84 tube into the Yel low Jacket. Make
sure that all pins are prop er ly aligned and do not force
any thing. It should all go smooth ly if the tube pins are
prop er ly aligned.
3. Turn the amp on, let it warm up, and play. Your amp is
now run ning in Class A mode with an EL84 output tube.
You do not have to adjust the bias of your amplifier as
the Yel low Jackets create their own cath ode bias cir cuit,
ig nor ing the bias setting in your amp. This also means
that when you put your old tubes back into the am pli fi er,
your bias will be set just as you left it.
®
™
Yellow Jacket
Tube Converter
YJShort
Hand-built in the U.S.A.
THD Electronics, Ltd.
3510 6th Avenue W
Seattle, WA 98119-1513
T: 206.781.5500 F: 206.781.5508
www.thdelectronics.com
Other Thoughts Regarding Yellow Jackets:
Other Thoughts Regarding Yellow Jackets:
This mod el of the Yel low Jacket converter, the YJShort,
is a specialized, cur rent-lim it ing/volt age-con di tion ing
adapter for use in most 20 watt to 100 watt am pli fi ers
which use 6L6, EL34, 6550 or 6V6 out put tubes. This
includes Marshall 50 and 100 watt tube amps, Fend er
Super Re verb, De luxe Re verb, Pro Re verb, Twin Reverb,
Bassman, Show man, Tweed Pro (5E5-A), Hot Rod De luxe,
Hi-Watt 50 and 100 watt amps, Sound City 50 and 100
Watt Amps, all Rivera amps, Jim Kelley, Soldano SLO and
Hot Rod Se ries amps, Mesa/Boogie 50 and 100 watt amps,
Bogner, VHT, etc......
Yellow Jackets are NOT to be used in amplifiers with
ex treme ly high plate volt ag es such as Marshall Ma jors,
Ampeg SVTs, Hi-Watt 200s and Or ange 120s. These am-
pli fi ers have too high a plate volt age and will dam age the
EL84s and pos si bly the Yel low Jackets them selves. While
the Yellow Jack et reduces the plate and screen volt ag es
each by 100 volts, this would still make the plate volt age
too high in certain am pli fi ers. If you are not sure if this set
of Yellow Jackets will work in your amp, please feel free to
con tact us at the fac to ry either by phone or by E-mail. We
will be happy to ad vise you on your individual situation.
Amplifiers which vary the bias voltage to create a trem o lo
effect will not have any tremolo effect when using Yel low
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 cus tom
ver sion of the Yellow Jacket (YJC) with a ground wire to
at tach to the chassis. This adaptor can be traded free of
charge for a YJC by contacting the factory direct at the
phone number or E-mail address on this card.
If your amp uses 6V6 output tubes and you do not want
a reduction in power, you need the YJ20 Yel low Jacket. If
your amp uses 7591 tubes, you should use the YJ7591 Yel-
low Jack et. The cor rect unit can be ob tained from the fac-
tory or from your local dealer, or this unit can be ex changed
for the one you need. Please con tact the fac to ry.
Thank you once again for buying our products. With out
cus tom ers like you, we would have noth ing to do all
day.
