A U D I O... P A P E R
Zen TORII Mk II designer's notes
2005 by Steve Deckert
this paper I will be covering the design and construction of the
new Torii in great detail because many of it's finer points would
never be known if I didn't. It's the sum total of these details
that make this amp superior to most of the ho-hum sounding push
pull amps out there. I consider this our flagship amplifier
although I prefer to call it our reference amp since audio
products labeled "flagships" tend to be more audio jewelry
than anything else.
I - I had a dream to build an amp like this many years ago...
a short story that explains what motivated me to build this.
II - Why the original TORII was replaced with this new design...
a brief explanation of what could be improved.
III - First attempt at replacing the original TORII circuit...
it wasn't going to be that easy.
IV - Designing a pentode circuit to be linear with zero
feedback... now I know why so few designer's accomplish
this with success..
V - Simpler is usually better... I have collected around
800 interesting schematics for push pull tube circuits over
VI - Why 25 watts beats more power... this is the cutoff
point in the grand power vs. fidelity scale.
VII - Construction Details... and parts descriptions.
VIII - Listening
tests... and general ramblings.
had a dream to build an amp like this many years ago
interesting the full circle I've come in my personal audio journey.
It's one that started in the 1980's when I discovered that
I could afford tube amps if I could just learn to fix them. You
could buy vintage push pull amps for less than fifty bucks at garage
sales all day long. They were ugly and needed plenty of attention,
but they sounded so much better than the Pioneer and even Harmon
Kardon receivers that were so popular throughout the 70's. My
plan was simple: Get the schematics from the library (Sam's
photo facts), use my wood working skills to create a beautiful chassis
and change the layout of the parts to a symmetrical balanced look.
Then simply wire it all up again and I'd have a killer amp.
With a solid background in electrical contracting and computer
programming and hardware design I figured it couldn't be that hard
to figure out how amplifiers worked so I jumped in with both feet.
Turned out I had no idea how complex analogue circuit design
was. I wired my first one up so it looked like a masterpiece
inside and plugged it in with great anticipation. The only thing
that came out of it was smoke.
spent every evening for 30 straight days trying to make it work.
Every time I got ready to plug it in for another test my heart would
start beating widely and I would duck under the bench (a trick
I learned along the way while blowing up capacitors) just in
case. Finally on the 31st night I plugged it in and sound
came out! It's a moment I'll never forget. I did several
more in the coming years. They became ongoing experiments
as I discovered how to change the way they sound. I had a
lot of fun with it. I ended up with an old Stromberg Carlson
circuit, a push pull 35 watt amplifier that evolved to a point where
it was always the winner during comparisons. It took me to new places
during my listening sessions. I eventually discovered
it sounded as good or better than the high dollar tube gear I lusted
after but could never afford. By this time in my life I was hard
core into speaker design and making a living doing it, but the amp
gave me dreams of manufacturing tube amps that sounded better and
cost less so all of us poor bastards could have the last laugh.
an audiophile I had developed a good ear early in the game and my
hand built amps went from the best I'd ever heard - I'm on top of
the world - to unlistenable. It was like a roller coaster
and I was still too green to understand why. I could never
sell an amplifier that didn't sound great the vast majority of the
time you listen to it and I couldn't break past the 50/50 mark.
My original goal of selling a push pull amp was pushed aside.
About this time I restored some smaller single ended amps
by Zenith and RCA and started to notice they consistently sounded
better more of the time than all of my push pull amps. The
more time I put into to them the better they got until I found myself
listening only to them. With these designs I was hitting the
80/20 mark and discovering that 5 good watts is enough to get some
damn good sound. This is how the Zen Triode amp came to pass
as I discovered that 1.8 watts of triode was also enough to get
some damn good sound, it was ideal in fact for late night listening
on my 90dB speakers which I frequently used at the time.
learned two things since those days... A) It's easier to get the
sound I like from simple single ended triode circuits and B) To
get a push pull amp to sound as good truly separates the men from
the boys in amplifier design. When I came up with the great
sounding little Zen Triode amp I knew I had something I could sell.
Nevertheless, I never stopped trying to get the same sound
out of a higher power design during the past 15+ years. Most
attempts were single ended designs with multiple output tubes in
parallel to get the power higher. They never sounded as good
as the single tube per channel. I tried higher power tubes
to get there with a single output tube but it always took at
least two or more gain stages to drive them. These also never
sounded better than the simple little Zen. I've also tried
push pull circuits - so many I've lost track to some degree but
they too always fell short. The only design that succeeded
in being in the same league was the original TORII where I broke
some rules with output transformer theory. The tradeoff with
that amp was primarily power for fidelity. I got 12 watts
per channel out of what could easily have been 30 watts
with a conventional output transformer.
the original TORII was replaced with this new design
problem with the original TORII reinforces the fact that just because
you design and build a perfect working amplifier doesn't mean you
can build 100 more just like it and expect prefect results from each
one until you first know how. Ironically that knowledge
doesn't come until you get to number 25 or so.
With the original
TORII I used two single ended output transformers wired in series
to create the push pull output. Because
the amplifier used feedback and the transformers were single-ended
they had to match all the way up into the funny business
area above 50 kHz where it's impossible to accurately measure them.
What this meant is that I would have to build the amp first
to find out if a given pair of transformers would work together
without becoming unstable. It usually took 3 tries per amp
before finding suitable matched pairs. This was making production,
specifically labor go way over budget and frankly became something
I no longer enjoyed doing. From a karma standpoint I think
it's important to really get off of what you build. It's a
real shame too because they sounded really good. A perfect amp for
limited production or just a great amp for myself, but not something
I want to build hundreds of when I find myself rebuilding each one
3 times before it even leaves the bench.
attempt at replacing the original TORII circuit
enough, my first attempt at replacing the amp was to basically duplicate
the entire TORII circuit except to use conventional push pull output
transformers. This would double it's power and eliminate the possibility
of mismatched transformers and the resulting instability that usually
followed. However, doing just that confirmed that my wild
dual single ended series output transformers in the original TORII
were in fact the corner stone of that amps magic sound. (The
conventional transformers with twice the power didn't sound as good).
Basically it sounded okay, but as far as I was concerned
it wasn't too far away from being another ho-hum sounding push pull
amp and the world is full of them.
still had not obtained my goal to get a stable higher power amplifier
to sound as good or better than a Zen Triode and these first attempts
didn't sound near as good as the original TORII so the
a pentode circuit to be linear with zero feedback
knew the only chance in hell I had to get the amazing depth and
imaging of our Zen Triode amps would be to completely
eliminate feedback. Problem is that in a Pentode amplifier
eliminating feedback is very hard to do without getting a severely
tipped up frequency response. It's similar to building
a high performance engine with the throttle wired wide open
- just a host of problems waiting to happen as soon as you
start it up.
I ended up with was a choke regulated power supply using tube rectification. A
massive 15 Henry choke was used to achieve serious regulation resulting
in a ripple that for all intensive purposes is non-existent.
This is simpler, superior and more expensive than the typical
cop-out implementation of solid state regulation. (Well that's
sure to offend a lot of amp builders). It adds $90.00 more
to the cost. Of course the tube rectifiers also
adds another $60.00 over the solid state diodes that are so commonly
found in today's amplifiers.
next step was to create a tube regulated supply for the control
grids of the output tubes. This approach makes the family
of Pentodes that are compatible in this amp run far more linear
greatly reducing the need for feedback. Here again a few cheap
transistors are replaced with tube regulation that adds another
$70.00 to the cost. Starting to see why so many production
push pull tube amps use negative feedback?
this wasn't enough to keep the amp from going over the edge on the
increasingly popular single driver speakers like Fostex and
Lowther in the average listening room. However it did sound
perfectly great on conventional audiophile two and three way speakers
which I expect will be the dominating market for this amp because
of it's higher power. I made the decision at this crossroad to continue
working on the circuit so the amp would be compatible with the single
driver crowd because frankly high efficiency speakers
have greater potential for fidelity. I love a good audiophile
speaker just like the next guy but when you hear a great amplifier
on a good efficient speaker around 94dB or higher the dynamics and
resolution of detail is just simply superior. We've developed
several high efficiency speakers that sound great on our little
Zen Triode 2 watt amps but hearing the same speakers on an equally
good sounding amp with 10 times the power really opens the doors
to aural ecstasy and fun!
reach that perfect frequency balance where everything sounds full
and even without loosing the pristine detail on the top end I had
to create a delicate RC network for adjusting high frequencies. This
is perhaps the most important feature of the amplifier because you
can adjust the top end presence and detail perfectly for any given
loudspeaker. This makes it fully at home with single driver
high efficiency speakers AND conventional audiophile speakers.
is usually better
you examine tube push pull circuits you find the basic workhorse
of early tube amps was the grounded-cathode transformer-coupled
output stage. It was usually biased in class A or heavy class
AB. Then you find amps that use a fixed bias to increase efficiency.
These circuits are more complicated requiring a negative voltage
supply and this is usually about the time you find hum balance pots
and overly busy circuits as designers focus on specs and greater
power output more than fidelity. In my experience fixed bias
amps don't sound as good, and the constant need to adjust the bias
gives tube amps a bad reputation for being high maintenance. Another
thing that gives tube amps this reputation is that so many are built
using circuit boards. The heat from tubes when combined with
circuit boards always leads to dried out boards that crack or simply
fail from the current trying to go through paper thin traces of
foil on the board. It is far superior to eliminate the circuit
boards and use real wire and point to point assembly.
has also become a very popular configuration to the point where
audiophiles blindly assume it's always better than an amplifier
that is not ultralinear. Ultralinear further increases efficiency
allowing the amplifier to develop more power into load. Since so
many people think more is better they're not likely to hear the
superior difference tube regulated grids make when using a transformer
without the ultralinear tap.
25 watts beats more power
power comes complexity. There is another reason why I choose 25
watts over 40 or 60 watts. My friend Paul and I call it "usable
watts". It simply means how loud can you turn an amplifier
up before the sound stops getting better and starts getting worse.
It's about class A vs. Class AB or Class B. I've set
up this amp at 47 milliamps per tube at idle with a fairly low plate
voltage to achieve class A output throughout it's power range. This
is the least efficient form of operation. By running the tubes
at a lower bias current the overall heat developed at the power
transformer would drop, and the power into load would go up. The
catch is that by doing so you drop the class A operation in
exchange for class B at some point as the amplifier is turned up.
So you might have a 40 watt amplifier but it may only run
in class A for the first few watts. To our ears that means you have
a 40 watt amplifier with only a few usable watts. The 25 watt
amp that is always in class A operation gives 25 usable watts so
we find ourselves being able to enjoy higher volume levels on the
lower powered amp.
VII - Construction details
new TORII is built as two separate mono amplifiers each with their
own power supply like the original Torii was. Rather than
build it in another five sided steel chassis with a bottom plate I
choose to make the new TORII from 1/8" thick aluminum
plates. It makes it considerably stronger and the higher mass and
stiffness helps to reduce resonance's. This way we can make wood
bases that will enhance and offer variety to the appearance.
layout was carefully designed so that the entire audio circuit could
be done point-to-point using mainly parts leads. This eliminates
most of the hookup wire and extra solder nodes and is not unlike
our original Zen Triode amps. The jacks and switches are aligned
along the back of plate and I have to say now that I've built a
few, that's a feature I really like. This layout was
first tested in a hand drilled steel chassis and found to work very
well. As you can see it is a dual mono mirror image symmetrical
layout. This will keep the wire lengths throughout the circuit
exactly the same lengths and orientation from one channel to the
we start at the beginning, the IEC connector that receives the removable
power cord is the most expensive one I've found. You can find
IEC connectors all over the place that look just as good for less
than a buck, but I've always stuck with the best to ensure the best
connection possible and long term reliability. Doesn't make
much sense to plug an expensive power cord into a 89 cent IEC connector.
This particular one has a hidden fuse holder integrated into
it complete with a spare fuse inside. On the back of the IEC
is a .02 uf poly cap to filter off noise and RF coming in on the
power cord. This is the only item besides the aluminum plate
that is common to both amplifiers (or channels). Each
channel has it's own power switch. Again, these are the expensive
Mountain switches that run $4.70 each. You can find exact
looking clones of them everywhere for 75 cents. Don't make
much sense to have a good power cord, wireless fuse holder and high
end IEC connector if your going to blow it with a cheap switch.
IEC connectors feed our proprietary US made 150 milliamp 600 volt power
transformers which were made with heavy gauge lead wires and oriented
so that the primary voltage (black wires) are not intermingled with
the secondary wires (yellow, green and red). This transformer
is significantly oversized to drive the 100 milliamp high voltage
load and has no mechanical vibration or hum. As you can see
the transformer leads go directly to their destinations via the shortest
path possible. This keeps the AC fields to an absolute minimum.
The heater wires (purple) are run individually in twisted
pairs of stranded wire to each tube. They are also have a clear
heat shrink tubing applied to them to keep the twists as tight as
possible which prevents them from loosening over time.
choose tube rectification for this amplifier for a few reasons.
The reliability is superior over solid state diodes because
diodes can fail from voltage spikes. Of course tube rectifiers
can too but in general they are a lot tougher and most importantly
IF one does fail, you can simply plug a new one in. When solid
state diodes fail you have to send your amp back to the manufacture
reason is sound quality. It's simply easier to maintain a clean
and grain free midrange and treble with tube rectification. It
is also possible to change the character of the sound by rolling
rectifier tubes. This amp uses either 5Y3GT's, 5AR4's or 5U4's
giving the listener a wide variety of signatures to work with. Between
the two extremes, a 5Y3GT and a 5U4, you will see around a 30 volt
difference in the DC high voltage feeding the plates of the output
tubes. This increase or decrease in voltage will shift the tubes
slightly towards different operating points of their plate
and grid curves, hence changing the sound.
pair of solid state diodes and the snubber caps and resistors required
to replace a tube rectifier would cost around five bucks. The
tube rectifiers/sockets in this amp increase the cost by around
$60.00. I felt it was money well spent.)
REGULATED POWER SUPPLY
over the original Torii is the choke regulated supplies. It's
the simplest and most effective way to get the job done.
15 Henry chokes rather than the more commonly used 5 or 8
henries just takes things a bit further. You can see the chokes
located just behind the power transformers. In the previous
picture they are the black twisted wires leading to the blue filter
capacitors. The alternative to using a choke while still keeping
things simple and straight forward (but less regulated) is
to use a high wattage resistor like I did in the original Torii,
but the results cause you to make a choice between quiet operation
with more heat OR better dynamics with less heat and more hum. (The
chokes add between $75 and $90.00 to the cost of this amp but the
advantages well justify the cost).
chokes work in harmony with the filter capacitors to remove AC ripple
(hum) in the DC voltage. If you look at the photo prior to
the one above, you can see the filter caps (light and dark blue)
are SPRAGUE ATOM and NICHICON known to be the best available. I
can confirm this with 10 years of experience using them. They
simply don't fail unless something is severely wrong. Most
importantly they carry current well. Most of the electrolytic caps
available today while carrying the same voltage specs are downsized
and drop the ball in a hurry when you ask them to do any real work.
Using boutique "audiophile" caps such as Blackgates
and similar over priced brands I find that they do not offer a proportional
increase in performance in our products, but they do seem to have
to be re-burned in every time you let the amp sit for any significant
length of time without use, something I could do without. Again
it doesn't make much sense to use high quality caps and a choke
regulated supply if your going to shove it through a cheap 5 watt
ceramic resistor in the last stage of your filter section to feed
the critical small signal tubes. Again, in the same photo
you can see I'm using a VISHAY DALE 10 watt wire wound in this position.
(Ceramic / 50 cents, DALE / $4.00). These are ideal
resistors to use because they simply never fail, especially when
oversized as they are here.
you just don't see very often unless it's a very expensive amp.
Part of the reason for that is the complexity of so many tube
regulation circuits. It's real easy for the tube regulation
to be more complex and costly than the entire amplifier it serves.
Does it have to be complicated to work right? Apparently not.
Altec had a simple way of doing it back in the late 50's and
I saw no need to re-invent the wheel so made the same choices.
a single OA3 vacuum diode were able to regulate the grids of the
output tubes and everything down stream of it. This was an
essential part of this circuit design to achieve linearity without
feedback as talked about earlier. The alternative is to just
leave the regulation out entirely. I spent an evening
with the prototype amplifier doing some serious listening before
adding the tube regulation and then again after adding it to see
if it was worth the cost. I decided it was worth 4 times the
cost. You can see the OA3 regulators in the picture above
with the bright glow at the top of each tube.
you finally "get it" that the ground potential and power
supply are part of the signal path, you realize that using the steel
or aluminum chassis for the ground would be as counter-productive
as sticking a Radioshack $1.99 cable on the end of a high dollar
pair of audiophile interconnects. Even the first Zen Triode
amps used a silver litz wire as the ground buss - not the chassis.
In this amp I choose to use a 10 gauge solid copper buss because
the silver litz wouldn't handle higher currents as well and frankly
the solid copper may even be better. Keeping the buss symmetrical
keeps the signal path identical for both channels.
you can see the DECWARE logo is lazar cut completely through the
chassis so that we could place the indicator lights inside the chassis.
That way you can see instantly when you flip either half of
the amp on that you have power. You don't have to wait for
the tubes to slowly start glowing to find out. (A really
long wait btw, when the amps not plugged in)
than use LED's for indicator lights (they can inject noise in
some circuits) I choose to use very high quality indicator lamps
driven of the AC heater supply. These lamps have been known to last
20 years without service. Should one go out for any reason
you simply change the bulb. These lamps flood the inside of
the chassis to create an even glow through the Decware logo by reflecting
off the bottom plate. You can change the color of the light
by changing the jewels shown in the picture above. I will be shipping
them with red jewels but you could change them to yellow, orange,
blue, purple or even green or white. Again, this costs 15
times more than an LED but it will never irritate you in a dark
room, or add grain to your sound.
input stage is down wind of the tube voltage regulation and further
regulated by polypropylene caps. About six times the
cost of electrolytic's but essential for keeping the sound glass
smooth and liquid. The input stage is the 6922/6DJ8/6N1P a
single triode with two halves. The first half is used as a
simple single ended gain stage that is direct-coupled to the second
half which acts as a phase splitter to drive the output tubes. This
approach eliminates the coupling cap that would normally be seen
here and keeps the phase shift down to an absolute minimum. I
have found no other combination to be as coherent, dynamic or
transparent when driving a pair of output tubes. This gives
enough gain to reach full power on a 2 volt source making preamps
stage is fed off an ALPS 100K pot which is located on the physical
path between the input jacks and the input stage. That makes
it possible to keep the interconnect between the jacks and the stage
as short as possible. I this amp I made special interconnects
from silver plated stranded copper wire with Teflon insulation by
threading both the positive and ground from the jack through a braided
nickel steel shield that is grounded directly the copper buss. This
is a cost-no-object approach to the input cable but it's a difference
you can really hear, with a noticeable increase in smoothness and
detail. This combined with the high quality Gold/Teflon RCA
jacks ensures that even interconnects costing several thousand dollars
can be used without fear of the signal being compromised.
would look into the bottom of a point to point wired amp and think
it looks like a bowl of pasta - especially when compared to the
neat appearance of circuit boards. The irony is that while visually
it may look inferior, electrically it's a work of art with dozens
of advantages not the least of which is better sound and reliability.
the point to point wired amps you might look under the lid of a
vintage QUAD amp and be impressed with how neat and square to the
world the wiring is, but upon further examination you realize there
is a hell of a lot of wire. Basically you have wires going
to every pin of each socket that connect to the individual parts
which then connect to more wires.
approach looks neat but the bundled groups of wire are all talking
to each other through small magnetic fields and degrading the signal
with twice as many solder joints. The way we do it is to connect
each part to the other via the parts leads directly wherever possible
to eliminate the wire and extra solder joints. You end up
with a very 3 dimensional layout that upon close examination is
extremely logical and well thought out.
audiophiles favorite part to modify... on the new TORII we
recommend you please don't. The caps used have been selected
for their benchmark coherency and the popular boutique audiophile
caps have all been tried. These particular polypropylene film
caps are made by General Electric. (A company with 100
million times the assets and resources of most boutique cap manufactures.)
I have configured each coupling cap by using two in parallel
each oriented in the opposite way. Even through poly caps
are usually bi-polar, they are still wound from the inside out so
there is bound to be a small change in the phase shift of the signal
passing through it one way vs. the other way. By using a pair of
identical matched values that are flipped with respect to each other
we can be sure whatever happens on the positive cycle will be exactly
duplicated on the negative cycle. In listening tests I can
assure you this configuration had extraordinary clarity well above
my expectations. It does however mean you have to buy 8 caps
instead of 4.
choice of output tubes in the new TORII greatly enhances the joy
of tube rolling. You can use EL34's or 6550's or KT88's each with
excellent results. All three sound a touch different. (It
is important in this amp that you run matched pairs of output tubes
because a non-matched pair can cut the overall power in half.)
Besides the difference in sound between the three types of
output tube you will also find differences in sound between the
same types of output tube in different brands. All three of
these tubes draw between 43 and 47 milliamps at idle, the perfect
combination of class A operation and long tube life.
output transformers in this amp are not ultralinear making possible
tube regulation on the grids of the output tubes. These transformers
carry a 35 watt rating and have excellent bandwidth in this circuit.
They also feature individual taps on the secondary for 3.5
ohms, 8 ohms, 16 ohms, 250 ohms and 500 ohms. No series/parallel
combining of various taps to get the value you need. I have
configured the amp with 3.5 ohm and 8 ohm taps into a single pair
of binding posts (per channel) using a high quality switch to select
the impedance. This way you can change the impedance on the
fly while you listen and decide for yourself what tap sounds best
on a given pair of speakers.
250 ohm and 500 ohm taps from the output transformer can be used
to drive a headphone jack. This way you can listen to most
any headphone be it high or low impedance by simply plugging them
into the appropriate jack. With many headphones it should
be possible to also leave your speakers connected to the amp if
you choose to do so. With the average efficiency of headphones
being largely higher than loudspeakers you will find the headphones
get loud quick when compared to the loudspeakers which will be playing
at very low volumes. With the
deafening levels of power available at the headphone jacks and the
overall gain of the amplifier you'll want to be careful not to turn
the volume up quickly. Since most people wouldn't use a 25
watt power amp to drive headphones this option does not come standard
on this amplifier but is available as a custom request.
WBT binding posts used on the new TORII offer a high compression
connection to spade connectors and crimped wire ends up to 8 AWG
as well as banana jacks in such a way that even the most heavy overbuilt
speakers wires will not wear them out. Being top mounted means
you can easily get to them without crawling behind the amp making
it far easier to check your connections no matter if your amp is
on a rack or sitting on the floor.
VIII - Listening tests
the goal was not to make an inexpensive but unusually good sounding
push pull amp at a magic price point for the people who don't "get"
single ended flea power but rather to offer a product that sounds
as good or better than our Single Ended amps which have a world
wide reputation for sounding better than most other amps period.
I can tell you that's a tall order and attempting it at a
sane price put me under some extreme pressure. I am not one
who particularly works better under pressure, at least it never
feels like I'm doing better work. What the pressure does do
is keep you from saying your done once you get the amp to sound
good. In my case it's pure fear of failing that pushes me
to explore everything that is possible. The final stages of
the design, just like the ones before it, are tedious because the
listening tests switch from the bench to listening room, with proper
warm up and careful evaluation with every small change. It's
simply relentless hard work. Even though as I write this in
preparation for selling it, I don't know what other people will
think of it's sound I do know how it compares to our other amplifiers
and am very familiar with how people rate the sound of those.
I compare the Zen Triodes against it I find they have no significant
advantage over the new TORII in the sound stage. In imaging
I was shocked to find the TORII to be far more specific and honest,
perhaps because of it's effortless headroom.
The overall character of the SE84CS was more polite and slightly
more laid back. Both amps are equally neural. The speed
of the SE84CS has become world famous, but sounds slower than the
TORII. Either amp have even a hint of grain or edginess, nor
are they forward sounding as each has incredible depth. However
the new TORII simply has more control and somehow considerably higher
resolution. The comparison with the TABOO was similar when
it was in standard mode and that also surprised me a little bit.
The new TORII made the Taboo and the Select sound very close
I guess because it sounds so different. Then I prepared to
see things get interesting as I flipped the TABOO into lucid mode.
The sound popped out and bloomed reaching the same boundaries
and general sense of presence I was hearing in the TORII. God
Bless the little guy, it almost did it but on careful listening
the TORII just did it slightly better and with considerably more
a really good HD READY LCD or PLAZMA television display and watch
a really good DVD movie on it. The clarity of the picture
and color depth is wonderful. Then on the same display watch
a show that was shot with High Definition Cameras. This is
the closest thing I can come up with to compare the sound of the
new TORII to even our single ended amplifiers. By the third
night of listening I concluded that many of my recordings were far
better than I thought they were and that through this amplifier's
ease and transparency I felt like I was listening to the recordings
as if they were naked. It was like hearing naked music without
anything attached to it without restrictions. Images have
clearly defined edges just as they do on High Definition TV.
IX - Conclusion
think this amp will impress audiophiles using most loudspeakers
assuming they realize 500 watt amplifiers always get louder and
sound worse than 50 watt amplifiers and 50 watt amplifiers always
get louder and sound worse than 5 watt amplifiers. And that
they strive to find the lowest acceptable point on that power line
that they think will still keep them happy. We already know
that magic number is 25 watts.
also think this amp will catch our own customers off guard as they
are far harder to impress. This is because it is fully at
home with high resolution/high efficiency speakers. My favorite
speakers on it are 94dB 1w/1m because they have the speed and resolution
to show off what the amp can do and because I can turn the amp up
to deafening levels without loosing "usable power".
having something that sounded as good as a Zen Triode amp that I
could play as loud as I want has been something I've wished for
ever since building the first Zen in 1996. I now feel like
I've reached that goal. I anticipate there will be those who
think this new TORII simply smokes our Single Ended Amps just as
there will be those who think the Single ended are better. It
boils down to the slightly romantic interpretation known to Single
ended amps vs. the more realistic (live) and honest presentation of this
will be our 10th year since this January since going on line in
1996. So it becomes approprete that this will be our 10th
aniversary amplifier as well as a turning point for our company
as we expand our niche of lower power amps to include everyone.
Decware has no plans to build a more powerful amplifier than this.
Unless you have very low efficiency (power hungry) speakers
this will be more than enough power. If you do have very low
efficiency speakers (84 dB or less) then the resolution and finess of this amplifier
may be wasted. Between 89dB and 94dB is an ideal efficiency
for this amplifier.