Decware Zen Taboo MK IV User manual

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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
The Zen Taboo MK IV
Planar Headphone
MANUAL NO. 01 REV. DATE: 5/20/2017
MODEL TABOOMKIV

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INTRODUCTION!
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The Taboo Mk IV is the end result of an amplifier design whose evolution spans over
thirteen years. What made the original design as well as the current one unique, was
the feature called “Lucid Mode”. This feature took the single ended outputs from each
channel, an output stage employing a virtual ground and a inverted positive feedback
loop and combined them in such a way as to create a cross-feed effect that works
without any filters or additional parts. With the introduction of the Mk IV, this effect is
now fully variable with a bypass switch.
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FEATURES!
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•Single-ended class A fully balanced output for headphones between 2 ~ 600 ohms
•Can also drive conventional loudspeakers on the desktop or listening room
•Inputs for two sources with optional transformer balanced XLR inputs for each
channel
•Dual Volume Controls for exquisite balancing with analog meters for each output tube
•The world’s best cross-feed called “Lucid Mode” with full adjustable level and bypass
•Hi & Lo output modes to accommodate both efficient and non-efficient headphones
•Drives Planar Headphones and Dynamic headphones with 1700 mW per channel
•Cryogenically treated Beeswax Caps, UFO wide bandwidth output transformers and
NO circuit boards.!
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com

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START UP!
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1. Install the tubes into the correct locations using the picture below:
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When you first get your Taboo Mk IV be sure to tube it up with the factory supplied
tubes. These have been carefully tested in the amplifier and are reference quality.
NOTE: We may ship your amplifier with a RECTIFIER tube made by ValveArt called a
274B. This is because we have found this rectifier to be the best sounding in current
production. Do not confuse this tube with a New Old Stock 274B or one from TJ Full
Music Company as those tubes are not compatible with the Taboo or any Decware
amplifiers. The ValveArt 274B is just a ruggedized 5U4 that also happens to sound
better.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
OUTPUT TUBE!
EL84 or 6P15P-EV
RECTIFIER!
5U4
OUTPUT TUBE!
EL84 or 6P15P-EV
INPUT TUBE!
6922

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If you would like to experiment with other tubes to see how the sound changes, you
should know that the input tube is the one that makes the biggest difference. We
usually ship the Taboo with a 6N1P-EV which is a military grade Russian tube similar to
a 6922 but slightly warmer sounding and usually longer life.
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Compatible Input tubes with the Taboo Mk IV
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•6N1P-EV - warmest of all likely alternates, slightly lower resolution.
•6DJ8 - leaner bass, more exotic top end and overall clarity.
•6922 - more clarity, better dynamics.
•6N11 - more clarity, more speed.
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The largest of the four tubes is an 8-pin tube also known as an octal tube. This is your
rectifier. There is a centering pin with a locator on this tube so that the tube isn’t
rotated out of position. The centering pin is longer than the tube pins so use it to locate
the correct rotation of the tube and then insert the tube into the socket.
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The remaining three tubes are 9 pin tubes and are located by a simple gap between
two of the pins. Simple observation makes it easy to correctly install these tubes. Just
make sure the smaller tube pins of these tubes are not bent because damage could
occur to the tube socket on the amplifier.
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If your 9 pin tubes have bent pins, they can be easily straightened with a tube pin
straightener occasionally available on eBay, or pins can be individually straightened
with a small needle nose plier.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com

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START UP CONTINUED!
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2. Install your sources using the picture below:
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Your Taboo has accommodations for two sources.
Input A and Input B. When the Taboo is built with the
XLR option, the XLR and RCA jacks both share input
A assuming you will only use one or the other. For
example, you can have two RCA sources, or one RCA
source and one XLR source.
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There is a source switch for each channel
located just in front of the RCA jacks.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
LEFT XLR !
INPUT A
LEFT RCA!
INPUT B
LEFT RCA!
INPUT A
RIGHT XLR !
INPUT A
RIGHT RCA!
INPUT A
RIGHT RCA!
INPUT B
SOURCE SWITCH

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START UP CONTINUED!
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3. Install the power cord and speakers.
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Insert the power cord and take a moment to notice the hidden door for the 3 amp fast
or slow blow 5x20mm fuse. It can be pried open with a small screwdriver to reveal the
fuse. There is also a spare fuse inside.
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If you plan to use the Taboo to drive loudspeakers, hook them up to the speaker jacks
shown below. Red is + and Black is -.
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Do not hook the two black speaker jacks together or to ground as the Taboo will not
work properly.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
POWER SWITCH
HIDDEN !
3 AMP FUSE HOLDER
SPEAKER JACKS

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START UP CONTINUED!
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4. Turn on and watch meters shown in the picture below.
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There is a meter for each output tube of which there is one per channel. Once you turn
on the power, all the tubes will begin to glow. It takes about 5 to 10 seconds or longer
to see the glow. How easy it is to see will depend on how dark the room is at the time.
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Once the tubes begin to glow they will also start conducting current at which point you
will see the meters lift off zero and rise to somewhere between 20 and 40 on the dial.
These readings indicate milliamps. As long as each tube falls between these two
numbers it is ok to use. If a tube reads higher or lower it should not be used.
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Average tube life is 3000 ~ 6000 hours. !
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com

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START UP CONTINUED!
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5. Set Volume and insert headphones.
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The Taboo has two volume controls, one for each channel. They are located directly
under each meter. In the picture these controls are shown with black chicken head
knobs, but there are many knob options so your knobs may look different.
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Always have both volume controls turned all the way down (counter-clockwise) until
you connect your headphones, then slowly raise the volume controls.
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The headphone jack is a 4 pin XLR. To the left of the jack is the HI/LO switch. It simply
adjusts how loud the headphones play relative to the volume control. If you hear any
hum, set the switch to the lower setting.
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You are now ready to listen to music.!
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
RIGHT VOLUME
LEFT VOLUME
HI / LO SWITCH

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OPERATION!
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1. Lucid Mode controls are shown below.
To use lucid mode, you simply adjust the dial to the desired amount by using the
bypass switch to A/B the effect vs. no effect. That way you can clearly hear what it
does and quickly discover how the effect acts differently on different recordings.
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When the dial is fully counter-clockwise the effect is difficult to detect right away. When
the dial is fully clockwise the effect is obvious.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
BYPASS SWITCH
LUCID MODE DIAL

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HEADPHONE DETAILS!
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The Taboo uses a 4 pin XLR headphone jack because the output of the Taboo is fully
balanced and if you combine the grounds together like is done in a 1/4 inch jack, lucid
mode will not function. With a 4 pin XLR jack the headphone cable has 4 conductors,
a positive and negative for each channel. This arrangement also typically sounds
better than a cable with only 3 conductors.
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Below is the pin out of the Taboo 4 PIN XLR headphone jack.!
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com

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OPERATION CONTINUED!
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1. Lucid Mode
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Lucid mode accomplishes two things:
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1. Cross-Feed where information from the right channel is present in the left channel at
the proper level and frequencies to simulate the effect one gets from listening to
loudspeakers in a room.
2. Extraction where information buried in the recordings is flushed to the surface
adding to a more live feel with more presence.
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The first half of the dial is cross-feed. The second half of the dial is extraction. That is
to say that when you pass the half way point on the dial, cross-feed turns into cross-
feed AND extraction with the level of extraction increasing as you rotate the dial to full.
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NOTE: Cross-feed is usually desirable on all recordings, however Extraction is more
recording dependent. For example, an audiophile recording can often sound really
good with Extraction, whereas a commercially typical recoding with lots of effects
patched into the recording console will often suffer from more than a tiny amount of
Extraction. Using too much will often ruin the recording. (The prior version of the Taboo
had Cross-Feed and Extraction on two separate switches and neither were adjustable.)!
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com

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HEAT / SAFETY!
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The taboo consumes 75 watts from the wall outlet so it puts out less heat than a 75 watt
light bulb and should have no problems on a shelf in an equipment rack. If the shelves
of your rack are wood, allow 4 to 6 inches above the tallest tube in the amp. If you
don’t have that much space there is a danger of the wood drying out over time and
eventually cracking. This can be avoided by adhering a piece of aluminum foil to the
bottom side of the shelf above the amplifier. While no harm will come to the amplifier
with 24/7 operation, it is good practice to turn off tube gear at night while you sleep
and when you are away from home.
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SPECIFICATIONS!
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Weight
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17 lbs. ea.
Dimensions
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8.5" H x 7.25" W x 14..75" D
Chassis
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Steel/Wood
Finish
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Black Powder Coat Typewriter Finish
Base
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Solid hardwood / user interchangeable
Circuit type
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Single ended Class !A Pentode
Power output
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4.6 watts into 8 ohms
Input voltage
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2.1 volts for full output
SNR
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-86dB
Response
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20 Hz ~ 80 kHz
Rectification
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5Y3GT / 5U4 / 5AR4 tube rectification
Output tubes
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SV83/6P15P-EB or EL84/6BQ5
Signal tube
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6922 / 6N1P
Transformers
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DECWARE UFO widebandwidth
Biasing
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Self-Biasing circuit - never needs adjustment
Resistors
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All resistors are precision WW/MF by DALE, VISHAY
Signal Cap
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Audiophile grade Cryo Treated Beeswax Paper Foil
Filter Caps
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Premium grade 500V electrolytic's
AC cord
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Fused IEC connector provided with removable power cord
Consumption
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75 watts at full power
Input jacks
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RCA type 24K Gold / Teflon
Output jacks
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Gold 5-way binding posts accept 8 gauge wire
Warranty
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Lifetime to original owner / 90 days on tubes
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com