Decware TORIIJR Owner's Manual
T O R I I J R O W N E R S M A N U A L
Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
The Zen Torii Jr. Amplifier
MANUAL NO. 02 REV. DATE: 09/2015
MODEL TORIIJR
T O R I I J R O W N E R S M A N U A L
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THIS AMPLIFIER IS FACTORY BIASED !
FOR THE SPECIFIC QUAD OF"
EL34 / 6CA7"
OUTPUT TUBES THAT IT SHIPPED WITH."
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DO NOT USE SUBSTITUTES OR EVEN DIFFERENT
QUADS of EL34’s UNLESS you RE-BIAS."
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
Have no fear, adjusting the bias is super easy in a DECWARE amplifier and will be covered in detail at the end of this manual.
T O R I I J R O W N E R S M A N U A L
FIG. 1!
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
Left
Channel
Source
Selector
Switch
RightLeft
Channel
Source
Selector
Switch
Power Cord
Jack
&
3 amp fuse
Hi/Lo
Speaker
Impedance
Switch
OA3
OA3
EL34
EL34
6922
EL34
EL34
6922
5U4
VOL
VOL
ON/OFF
Input Switch
Points to Selected
RCA Jack
Speaker Switch
Hi = Rear
Lo = Front
Hi/Lo
Speaker
Impedance
Switch
SPEAKER
NEG
SPEAKER
NEG
SPEAKER
POS
SPEAKER
POS
Turn Down Both Vol.
Controls Before Turning
Amplifier ON
BIAS ADJ
T O R I I J R O W N E R S M A N U A L
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INTRODUCTION
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The TORII JR. was designed to offer the sound and performance of our very popular
TORII MK IV amplifier at a more affordable price without compromises in performance
or sound quality. In fact, at the writing of this manual it is still unknown which of the two
amplifiers actually sounds better!
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The difference between the two is A) Physical Size, B) Adjustability and C) Power.
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The TORII JR is physically smaller made possible by using a single larger power
transformer to create a stereo amplifier vs. dual mono like it’s bigger brother.
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The TORII JR is a fixed bias amplifier set up specifically for a single type of output tube
so output tube rolling requires resetting the bias with each change unlike it’s bigger
brother.
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The TORII JR is a 20 watt amplifier, slightly smaller than it’s bigger brother.
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These changes while sounding like you’re getting less, may actually be giving you
more. For example, the smaller size makes possible a simpler internal layout with a
more direct signal path. The fixed bias and lack of output tube rolling, makes it
possible to dial the amp in slightly tighter and to a specific tube to maximize
performance.
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The less power is easy to overlook in side by side testing, as the TORII JR ’s ultra-linear
output stage has a higher level of control with wider bandwidth.
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The justification then for moving from a TORII JR to a TORII MKIV would be
adjustability. The adjustability can yield a potentially more or less forgiving sound
depending on what the owner wants.
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That said, we are certain that there is nothing you would want to change about the
sound of the TORII JR, so this isn’t likely to be a problem.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
T O R I I J R O W N E R S M A N U A L
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THE DECWARE ZEN LAYOUT
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All Decware amplifiers employee a Zen Layout, but this particular amp is one of the
best. No circuit boards are used and if you’ll notice, the layout is symmetrical and
done in such a way that the entire audio circuit can be created with only the parts
leads themselves. This reduces solder nodes, wire, dissimilar metals, noise, coloration
and increases sonics and reliability. This is the only way to make an amplifier that
sounds this transparent.
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You are looking at the entire audio circuit for one channel. Silver wired, silver bearing
solder, nice spacings to avoid magnetic field interaction between the parts, Impact
rated for 90G’s without lead bending during shipping and soldered by the best.
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You can now see why the amplifier has such breathtaking transparency and speed, …
both things that are diluted by complexity.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
T O R I I J R O W N E R S M A N U A L
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FEATURES
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Purist Signal Path
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Silver input selector is located between a pair of input jacks on either side so that
only a one inch piece of silver wire is needed to connect the two, which increases
transparency while still allowing for source selection.
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Dual volume controls are used and located 1 inch away from each input tube, again
eliminating large amounts of wire and further increasing transparency.
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To date the best internal layout of the original torii circuit with a 50% reduction in
solder nodes which increases transparency even further.
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Cryo Treated Beeswax caps are used just like the in the MK4, however in the TORII
JR, the value is 75% smaller giving a noticeable increase in speed and detail.
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OA3 Tube regulation is used to regulate and filter the voltage feeding each input
stage which effectively decouples it from the power supply for grain free sound.
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Dual Mono 500V F&T Power supply rails just like it’s big brother, the TORII MK4 give
better stereo separation and enhance headroom.
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UFO Output Transformers with ultra flat response and a bandwidth reaching out to
100 kHz makes it possible to hear the increase in transparency from all the
improvements listed above.
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The TORII JR. works well with or without a preamplifier.
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20 WATTS into 8 ohms with 4 & 8 ohm speaker impedance silver switch.
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Tube Rectification protects amps from large power spikes than can open or short
diodes and brings voicing opportunities to the customer.
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Direct coupled 6922 based input stage, same as in the TORII MK4, gives a world of
opportunities for subtle changes to the voicing by simply trying different brands of
this very popular audiophile input tube.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
T O R I I J R O W N E R S M A N U A L
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OPERATION
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Your TORII JR ships with matched quads of EL34 output tubes. If you ordered your
amplifier with stepped attenuators instead of standard volume controls, it is
recommended that you run matched input tubes to maintain perfect channel balance.
All TORII JR’s ship with carefully matched input tubes.
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As you can see, configuring your amplifier with stepped attenuators can complicate
tube replacement since all the tubes need to be more carefully matched. Again, the
reason for this it to maintain perfect channel balance. The exception would be if you
are running a preamplifier with either dual volume controls or a balance control, in
which case that can be used to match the channels even when the tubes on the left
side of the amp do not perfectly match the tubes on the right side of the amplifier.
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That said, once it is tubed up the sequence of start up is:
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1) Turn down left and right volume controls all the way.
2) Make sure loudspeakers are connected to the amplifier on both channels.
3) Turn on the power switch and wait for tubes to warm up.
4) Press Play, or lower the tonearm ; )
5) Slowly raise the volume on each channel to the desired listening levels.
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OA3 REGULATION
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You will notice that the OA3 regulator tubes will flicker on and off intermittently during
the first 30 seconds of warm up. This is because in order to make an OA3 “fire up” a
certain amount of current must be drawn across it. When you first turn on your
amplifier, the tubes are cold and are not conducting any current. Then as the input
tubes warm up and begin to draw current, electrons begin to flow inside the OA3.
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Understanding that the amount of current draw determines how the OA3 behaves, you
might also find it informative that the brightness of the glow is determined by the
current draw. Too little current, dim glow or possibly even flickering on and off. To
much current, bright glow and lots of heat created. Just right is a nice yellow/orange
glow with a temperature that you can keep you hand on for as long as you want.
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You will notice when you turn the amplifier off that the OA3’s may flicker on and off a
few times as well, doing basically the reverse of when you turned the amplifier on. This
is normal.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
T O R I I J R O W N E R S M A N U A L
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Additionally, it should be understood that an OA3 tube takes approximately 20~22
minutes to fully stabilize. During this period it is advised that you keep the amplifier on,
for at least 20 minutes. Following this regimen will ensure your OA3 tube lasts for many
years, if not the life of your amplifier.
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The OA3 is also known as a VR75. It is a vacuum diode that has a 75 volt drop across
it’s plate and cathode. This could btw., easily be done with a simple resistor, however
using the rare vacuum diode tube we gain 20 times more ripple (hum) reduction and
complete isolation from the power supply so that the power that feeds the input stage
is nearly perfect like a battery. This makes possible the jet black backgrounds you
hear that are essential to underpin the amazing layering that this amp projects.
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It should be mentioned that the voltage drop across the OA3 determines the DC
voltage that feeds the input stage. With an oA3, the input stage performs well with low
distortion and the maximum amount of clean gain. Occasionally when the full 20 watts
of the amplifier are not required, experimentation with VR90, VR150 tubes have proven
interesting. Since these tubes create a higher voltage drop, they also increase
isolation making them more like a pure battery. The increased voltage drop, lowers the
gain of the tube and increase the distortion of the tube once that gain window is
pushed. This results in a different clipping character and overall different sound to the
amplifier based on the particular input tube that is used. For example, you may drop
the power from 20 watts to 6 or 8 watts but within that zone realize better sound that
consequently better serves a high efficiency horn loaded speaker system.
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The OA3 is in series between the power supply and the input stage meaning it will also
become a fuse for the input stage should the input tube exhibit a catastrophic failure or
short. In that case, the OA3 will likely flash and go dark killing all power to the input
stage and saving the internal parts in the amplifier from excessive stress. There are no
heat producing parts internally therefor nothing internally in the amplifier fails unless
the fuse was tampered with.
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It is also worth mentioning that the OA3 tube does not get hot in this amplifier, but it
does get very warm. The other tubes in the amplifier by comparison can NOT be
touched. Temperature of the OA3 reaches around 105 degrees F. The EL34’s are
nearly 300 degrees F. The 5U4 typically runs at 220 degrees F (100 degrees
Centigrade).
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While we’re talking about temperatures, it should be noted that overall heat was a
careful part of the design, not an after effect of the design. Heat will be discussed in
it’s own section of the manual.
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Decware High Fidelity Engineering Co., East Peoria IL, USA www.decware.com
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