THD Electronics YJSD User Manual

THD Electronics, Ltd.

®

Yellow Jackets

™

1 Duet Tube Converters

YJSD

Handbuilt in the USA of US
and imported components.

Yellow Jackets

• Contains One Pair of Yellow Jacket™ Converters Model YJS and Two EL84 Power Tubes.

• Converts most amplifiers with 6L6s, EL34s, 6550s or 6V6s to EL84s 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.

• One Year Limited Warranty on Converters.

• “The next best thing to getting yourself a new amp.” - Guitar World Magazine

• “Increase amplifier flexibility”- Guitar Player Magazine

includes EL84 Power Tubes

™

THD Electronics, Ltd.

®

Yellow Jackets

™

1 Duet Tube Converters

YJSD

Handbuilt in the USA of US
and imported components.

Yellow Jackets

• Contains One Pair of Yellow Jacket™ Converters Model YJS and Two EL84 Power Tubes.

• Converts most amplifiers with 6L6s, EL34s, 6550s or 6V6s to EL84s 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.

• One Year Limited Warranty on Converters.

• “The next best thing to getting yourself a new amp.” - Guitar World Magazine

• “Increase amplifier flexibility”- Guitar Player Magazine

includes EL84 Power Tubes

™

®

THD Electronics, Ltd.

3510 6th Avenue W

Seattle, WA 98119-1513

Phone: [phone]

Fax: [phone]

[e-mail]

www.thdelectronics.com

Thank You!

Thank you for buying our Yellow Jacket

™

Converters! They will
provide you with years of service, assuming that you replace
the tubes when they are worn, and will also give you a much
greater variety of sounds from your amplifiers than you have
ever experienced before.

How to Install Yellow Jackets:

1. With your amplifier cold and turned off, remove the output
tubes from their sockets. (Use a towel to protect your hands
if the tubes are hot.)

2. Place the Yellow Jacket Converters in the output tube
sockets and install the provided EL84 tubes into the Yellow

™

Jackets

. Make sure that all pins are properly aligned and
do not force anything. It should all go smoothly if the tube
pins are properly aligned.

®

THD Electronics, Ltd.

3510 6th Avenue W

Seattle, WA 98119-1513

Phone: [phone]

Fax: [phone]

[e-mail]

www.thdelectronics.com

Thank You!

Thank you for buying our Yellow Jacket

™

Converters! They will
provide you with years of service, assuming that you replace
the tubes when they are worn, and will also give you a much
greater variety of sounds from your amplifiers than you have
ever experienced before.

How to Install Yellow Jackets:

1. With your amplifier cold and turned off, remove the output
tubes from their sockets. (Use a towel to protect your hands
if the tubes are hot.)

2. Place the Yellow Jacket Converters in the output tube
sockets and install the provided EL84 tubes into the Yellow

™

Jackets

. Make sure that all pins are properly aligned and
do not force anything. It should all go smoothly if the tube
pins are properly aligned.

3. Turn the amp on, let it warm up, and play. Your amp is
now running in Class A Mode with EL84 output tubes.

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

If you have an amp with 4 output tubes, you have a number
of options:

a. Replace all 4 output tubes with Yellow Jackets.

b. Remove all 4 tube and put only 2 Yellow Jackets in the amp,
giving you about 20% power. In this case, install the Yellow
Jackets in the inner two sockets. (You do not need

continued on other side...

3. Turn the amp on, let it warm up, and play. Your amp is
now running in Class A Mode with EL84 output tubes.

-

You do not have to adjust the bias of your amplifier as the Yel

­low Jackets themselves create their own cathode bias circuit,
ignoring the bias setting in your amp. This also means that
when you put your old tubes back in the amp, your bias will
be set just as you left it.

If you have an amp with 4 output tubes, you have a number
of options:

a. Replace all 4 output tubes with Yellow Jackets.

b. Remove all 4 tube and put only 2 Yellow Jackets in the amp,
giving you about 20% power. In this case, install the Yellow
Jackets in the inner two sockets. (You do not need

continued on other side...

to adjust the impedance selector on your amplifier to com­pensate for using only two output tubes. You can keep it set
to the impedance of your speaker cabinet with no danger of
causing damage to the transformer.)

to adjust the impedance selector on your amplifier to com­pensate for using only two output tubes. You can keep it set
to the impedance of your speaker cabinet with no danger of
causing damage to the transformer.)

c. Leave two output tubes in the outside sockets and install
two Yellow Jackets in the inside two sockets. This will give
you a combination of Class A and Class AB operation, a very
cool, responsive sound!

Other Thoughts Regarding Yellow Jackets:

This model of the Yellow Jacket Converters, the YJSD, is a
complete set of specialized, current-limiting/voltage-condi
tioning adapters with EL84 output tubes for use in most 20
watt to 100 watt amplifiers which use 6L6, EL34, 6550 or
6V6 output tubes. This includes Marshall 50 and 100 watt
tube amps, Fender Super Reverb, Deluxe Reverb, Pro Reverb,
Twin Reverb, Bassman, Showman, Tweed Pro (5E5-A), Hot
Rod Deluxe, Hi-Watt 50s and 100 watt amps, Sound City
50 and 100 Watt Amps, all Rivera amps, Jim Kelley, Soldano
SLO and Hot Rod Series amps, Mesa/Boogie 50 and 100
watt amps, Bogner, VHT, etc...

Yellow Jackets are NOT to be used in amplifiers with ex
tremely high plate voltages such as Marshall Majors, Ampeg
SVTs, Hi-Watt 200s and Orange 120s. These amplifiers have
too high a plate voltage and will damage the EL84s and
possibly the Yellow Jackets themselves. If you are not sure
if this set of Yellow Jackets will work in your amp, please
feel free to contact us at the factory either by phone or by
e-mail. We will be happy to advise you on your individual
situation.

c. Leave two output tubes in the outside sockets and install
two Yellow Jackets in the inside two sockets. This will give
you a combination of Class A and Class AB operation, a very
cool, responsive sound!

Other Thoughts Regarding Yellow Jackets:

This model of the Yellow Jacket Converters, the YJSD, is a

-

-

complete set of specialized, current-limiting/voltage-condi
tioning adapters with EL84 output tubes for use in most 20
watt to 100 watt amplifiers which use 6L6, EL34, 6550 or
6V6 output tubes. This includes Marshall 50 and 100 watt
tube amps, Fender Super Reverb, Deluxe Reverb, Pro Reverb,
Twin Reverb, Bassman, Showman, Tweed Pro (5E5-A), Hot
Rod Deluxe, Hi-Watt 50s and 100 watt amps, Sound City
50 and 100 Watt Amps, all Rivera amps, Jim Kelley, Soldano
SLO and Hot Rod Series amps, Mesa/Boogie 50 and 100
watt amps, Bogner, VHT, etc...

Yellow Jackets are NOT to be used in amplifiers with ex
tremely high plate voltages such as Marshall Majors, Ampeg
SVTs, Hi-Watt 200s and Orange 120s. These amplifiers have
too high a plate voltage and will damage the EL84s and
possibly the Yellow Jackets themselves. If you are not sure
if this set of Yellow Jackets will work in your amp, please
feel free to contact us at the factory either by phone or by
e-mail. We will be happy to advise you on your individual
situation.

-

-

Amplifiers which vary the bias voltage to create a 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 (YJCD) with a ground wire to attach to the
chassis. This set can be traded free of charge for a YJCD set
by contacting the factory direct at the phone number or e­mail address on the other side of this card.

For 6V6 amps where you do not want to drop the power of
the amplifier(other than Jim Kelley Amps which require the
voltage reduction citcuitry of this YJSD set), the YJ20D set
can be ordered, and this set can be traded factory direct,
if you desire.

If your amp uses 7591 output tubes, you need the YJ7591D
Yellow Jackets, which can also be obtained from the factory
or from your local dealer, or this set can be exchanged for
the YJ7591D set. Please contact the factory.

Amplifiers which vary the bias voltage to create a 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 (YJCD) with a ground wire to attach to the
chassis. This set can be traded free of charge for a YJCD set
by contacting the factory direct at the phone number or e­mail address on the other side of this card.

For 6V6 amps where you do not want to drop the power of
the amplifier(other than Jim Kelley Amps which require the
voltage reduction citcuitry of this YJSD set), the YJ20D set
can be ordered, and this set can be traded factory direct,
if you desire.

If your amp uses 7591 output tubes, you need the YJ7591D
Yellow Jackets, which can also be obtained from the factory
or from your local dealer, or this set can be exchanged for
the YJ7591D set. Please contact the factory.

Thank you once again for buying our products. Without
customers like you, we would have nothing to do all day.

- All the folks at THD Electronics, Ltd.

Thank you once again for buying our products. Without
customers like you, we would have nothing to do all day.

- All the folks at THD Electronics, Ltd.