Premium HP - Sound Mania
PrimaLuna DiaLogue
Premium HP
ver since I reviewed Prim-
aLuna's ProLogue Premium,
for the June 2012 issue, it has
been the model I would turn
to when I wanted a moderately priced
integrated amplifier to try with a new
speaker! It never disappointed me, and
never seemed outclassed, even when
the speaker was the MartinLogan
Montis ($10,000/pair). At $2399, the
| ion Tubed, remote-
controlled, stereo integrated
amplifier. Tube comple-
ment: six 12AU7, eight EL34;
KT88 or KT120 tubes also
16dBW), 42Wpc (KT88,
16.23dBW), 45Wpc (KT120,
16.53dBW): ultralinear mode,
70Wpc (EL34, 18.45dBW),
ProLogue Premium to me represents
the “sweet spot” for systems in the
range of $4000-$10,000 or higher. Al-
though its 35Wpc may not be enough
for some speakers (depending on the
room and personal preference), I never
had any such problem, regardless of
whether the speaker had a built-in
powered subwoofer (eg, the Montis
or the GoldenEar Technology Triton
(EL34, KT88), 360mV
(KT120). Input impedance:
100k ohms. Power consump-
tion: 470W (EL34), 480W
Two) or was a passive design (Wharf-
edale's Jade 7 or Focal's Aria 936).
With differences noted depending on
whether EL34 or KT88 output tubes
were used, the ProLogue Premium de-
livered sound that was always smooth
and musically involving.
The first mention I saw of the
DiaLogue Premium HP integrated
was in a report by Jason Victor Serinus
from the 2014 Consumer Electronics
Show? He'd been impressed with
the sound of the system that featured
the Premium HP, describing it as
“really nice, with very natural timbres
that rival or surpass those of the
high-priced spread,” and quoted
PrimaLuna's Kevin Deal: “It's the best
amp we've ever done.”
Hmmm. Sounded like something I
needed to check out for myself.
Description and Design
If you gave the DiaLogue Premium
HP ($4199) only a brief glance, you
might mistake it for a ProLogue
Premium. However, placing the two
1 See verre pe coul Content pri Ks.
2 See
number of dealers: 65.
| + Durob Audio
BV, PO Box 109 ‚ 5250 АС
Vliimen, Netherlands.
Tel; (31) 73-511-25-55.
available. Inputs: 5 pairs
RCA, 1 pair home-theater
bypass. Outputs: 4 & 8
ohms. Subwoofer output:
RCA. Headphone output:
1/4" stereo jack. Rated output
power into 8 ohms, 1% THD:
triode mode, 40Wpc (EL34, = December 2014
73Wpc (KT88, 18.63dBW),
85Wpc (KT120, 19.3dBW).
Frequency response, £1dB:
7Hz-65kHz (EL34), 7Hz-
70kHz (KT88), 7Hz-75kHz
(KT120). THD (1W/1kHz):
<0.1%. Signal/noise: 92dB
(EL34, KT88), 93dB (KT120).
Input sensitivity: 320mV
(KT88), 540W (KT120).
TT ns 15.9" (410mm)
A by 8.1" (210mm) H by
2" (390mm) D. Weight:
e 3 his се
4 R577972 E
ing); D8698479 (Mmeasuring).
$4199. Approximate
US distributor: PrimaLuna
USA, 1042 N. Mountain
Avenue, #B, PMB406,
Upland, CA 91786.
Tel: (909) 931-0219,
Web: www.primaluna-usa.
models side by side makes their physical differences obvious:
the DiaLogue Premium HP has eight rather than four out-
put tubes, and six rather than four small tubes. And if you
were blindfolded and asked to lift each amp—the ultimate
blind test—you’d have no difficulty telling them apart. At
46 lbs, the ProLogue Premium is heavy—but the DiaLogue
Premium HP is really heavy: 66 lbs. The DiaLogue Premium
HP also has a headphone jack, a switch on the right side for
selecting between speakers and headphones, and two small
indicator lights on the front panel, to signal whether the
amp is operating in triode (green) or ultralinear (red) mode.
It would take two pages of small print to describe all of
the features of the DiaLogue Premium HP, as it does on
PrimaLuna’s website.” T won't duplicate all that information,
but here are the salient differences between it and the
ProLogue Premium. The DiaLogue Premium HP has:
}} Dual Premium Adaptive AutoBias boards, with twice
the number of output tubes and the circuitry to support
them. Kevin Deal notes that PrimaLuna could have raised
the power by running fewer tubes harder, but their more
conservative approach results in less wear on the tubes.
The Adaptive AutoBias circuitry includes protection, and
a Bad Tube LED indicator if a tube fails. PrimaLuna's
implementation of the autobias principle is said to be more
sophisticated than that of most manufacturers, who use
cathode autobias only.
)) All-tube headphone amplifier built in. This is not selected
with a simple switch, but with relays that open and close to
reduce any interference. I don’t use headphones for serious
listening, so I couldn't verify Deal's claim that the Premium
НР”: headphone amp “will compete with the best,” but I
must say I've never heard my ancient Grado SR 125 phones
sound so good.
)) AC Offset Killer ensures that the power transformer
doesn’t hum, even in areas with bad AC.
)) New front-end design, using six 12AU7 tubes instead
of four, is said to result in better dynamics and wider
1) Triode/ultralinear switching on the fly via remote
)) Swiss-made wiring of silver-plated copper with Teflon
dielectric in all signal paths.
1 Audiophile-grade Takman resistors from Japan used in
the signal path.
1) SCR tinfoil caps in critical positions.
Setup and System
Setting up a solid-state amplifier for review is a pretty
simple matter. About the only decision you have to make is
whether to use the single-ended or the balanced inputs (if
both are available). Then its just a matter of swapping the
amplifier to be tested for the reference amp, turning on the
system, and listening for similarities and differences.
For a tube amplifier, it’s a bit more complicated: You
may have to decide what output terminals to use—4, 8,
or 16 ohms, (assuming that all of these are provided; the
DiaLogue Premium HP omits 16 ohms)—but that’s about
it. I had found that I slightly preferred the sound of the
ProLogue Premium’s 4 ohm terminals with the Focal Aria
936 speakers, which I also used for this review. I briefly
listened to both sets of the DiaLogue Premium HP's output
terminals, and again, the Focals sounded better through the
4 ohm taps, which I used for the rest of my listening.
But this was only the beginning. The DiaLogue Premium
3 See 34-dl-prem/196-dl-premiumHP-int.
т se => =
чет —- Fi = meme EE Sm
2 y review sample ofthe ~ Premium HP to warm ai an NOE or
PrimaLuna Dialogue so, | used my Audio Precision SYS2722
Premium HP (a dif- system (see the January 2008 “As We
ferent one than that See It” and to examine —o Spies ely. Te A
auditioned by Robert Deutsch) was its measured performance. With 4 “fier étre absolute Pen de
fitted with EL34 output tubes—| made — and 8 ohm output-transformer taps ‘was non-inverting) in all four output —
sure that the bias was correctly set and the choice of triode (green LED _ conditions. The input impedance was -
for these tubes before performing any illuminated) or ultralinear (red LED) ~~ 32k ohms from 20Hz to 20kHz. This E
testing. After allowing the DiaLogue operation, the DiaLogue Premium HP usefully high, but still much over tan
: is four amplifiers in one; | looked aa all ok the specified 100k ohms. ER
| four output conditions. a. The output impedance depended
a | 39), The lowest maximum gain wasin on frequency, the tra er tap, nd
| triode mode efron the4 tn at = the mode of operation. The lowest ©
8 E
r + | | | i | | | |
2 - | a | |
| Нор | = о | EE = 0 al A
10 20 50 100700 500 ik 2k ir 10K 20K BOK 200k | E | E = | |
7 Г = | | | | Е | | | | Te
Fig. PrimaLuna Dialogue Premium HE, om. Er 05 1.0 15 20 [| am ac 0.10 0.15 om: e
tap, triode made, , frequency response with volume Time in ms a Time in ms Te
control at its maximum at into: simulated
loudspeaker load (gray), 8 ohms (left channel blue,
right red), 4 SER a magenta), 2 25
ohms (green) (2dB/vertica ;
Fig.2 PrimaLuna Dialogue Premium! HP 8 ohm ap. Fle.3 Primaluna Dialogue us HE, 8 ohm an ;
ultralinear mode, small- tea kine ma aa
into SMe: : To Bohms. frat = December 2014 135
HP can use a variety of output tubes, the choice of which
can have a major effect on the sound. The Premium HP
features autobiasing of output tubes; all you have to do is
select, with a rocker switch, the type of tube. (If the switch is
in the wrong position, this apparently does no harm; it’s just
not optimal in terms of ma ormance.) The amplifier comes
with EL34 tubes as standard; in addition, Deal offered to
send along whatever other tubes I was interested in trying.
Pm not inclined toward tube rolling, but I was curious about
the sound with KT120s, a new variant of the KT88 design
that has received mostly positive reports. (It’s used in the
latest Audio Research amps.) As with any audio product,
the praise for the KT120 has not been universal; some
have noted that this tube draws more current than KT88,
which may, over time, damage an amplifier not designed
for it. (McIntosh doesn’t recommend using KT 120s in their
MC275LE, my reference amplifier.) PrimaLuna, which has
a sterling reputation for amp reliability, endorses use
of the KT'120. I assumed they know what they're doing
and asked Deal to send along a set. I report below on the
differences I heard.
Nor was that the end of it. Whichever output tubes are
used can be used in triode or ultralinear mode. Put all this
together, and the DiaLogue Premium HP gives you a choice
of, effectively, eight different amplifiers: EL34 triode or
ultralinear, and KT120 triode or ultralinear, each with the
4 or 8 ohm output terminals.
My choice of Focal's Aria 936 speakers was determined
by several reasons: 1) at $3995/pair, the Aria 936 is
typical of the kind of speaker likely to be paired with a
$4199 integrated; 2) having reviewed the Aria 936 in the
I used the Babe mu
: was very familiar with its
DiaLogue 5 sound: 3) the Aria 936
Premium HP’S 4 has the transparency and
ohm terminals overall sound quality that
would allow me to evaluate
throughout the the quality of the driving
review. amplifier; and 4) I still had
the review samples of the
Aria on hand, and Audio
Plus Services, Focal's US importer, had no problem with my
holding on to them for a while.
My review sample of the DiaLogue Premium HP review
sample was the one that had been demoed at CES, so I
figured I didn’t have to worry too much about breaking it in.
Still, before doing any serious listening, I played a variety of
CDs at various levels, switching willy-nilly between triode
and ultralinear, and trying to dissociate my impressions from
the analytical critical part of my brain. Of course, the latter
is not really possible, and I quickly came to feel that, as good
as the ProLogue Premium is, with the DiaLogue Premium
HP PrimaLuna had taken a major step forward in amplifier
To more systematically examine the sound of the
DiaLogue Premium HP, I compared it and the ProLogue
at matched levels: <0.1dB difference, measured with a
voltmeter at the output terminals, using the 1kHz tone of
Stereophiles first Test CD (Stereophile STPH002-2). Both
amps had EL34 tubes installed, and the DiaLogue Premium
— =
rig, ea ne
ms y
dame was A the 4 e ap
in triode mode, at 1.1 ohms from 20Hz
to kHz, rising to 1. 33 ohms at 20kHz.
Ultralinear mode slightly increased
both of these impedances, by 0.1 ohm,
while the 8 ohm tap almost doubled
them. Even so, these impedances are
significantly lower than with other
PrimalLuna amplifiers | have measured,
and the modulation of the amplifier’s
frequency response by the interaction
of its output impedance with that of
the loudspeaker was relatively mild. It
ranged from +0.8dB from the 4 ohm
tap in triode mode (fig.1, gray trace) to
+1.3dB from the 8 ohm tap in ultralin-
ear mode. Note the peak between 30
and SOkHz in fig.1. This peak was at
its highest from both taps into 8 ohms
and higher impedances, but disap-
peared when the load impedance was
well below the nominal transformer-
tap value. But with the tap matched
to the load, this peak was associated
with a significant amount of over-
shoot on a 1kHz squarewave (fig.2),
though a 10kHz squarewave revealed
that the SER ringing was
critically damped (fig. 3), the A
maintaining its stability. The flat tops
and bottoms of these squarewaves
correlate with the amplifiers extended
low-frequency response; PrimaLuna's
output transformers are of excellent —
Fig1 was taken with the volume
control set to its maximum, and the
channel balance is excellent. | repeated
the response measurement with the
volume control set to 12:00, equivalent
to a gain reduction from the maximum
of 17dB (not shown), and the channel
— e
FigA. PrimaLuna Dialogue Premium HP, 4 ohm tap,
triode mode, distortion (96) vs TkHz. Continuous
output power into À ohms. ! = December 2014
Fig.5 PrimaLuna Dialogue Premium HP, 8 ohm tap,
triode mode, distortion (96) vs 1kHz continuous
output power Into $ ohms.
Fig.6 PrimaLuna Dialogue Premium HP: 4 ohm tap,
ultralinear mode, distortion (9%) vs kHz continuous
output power into 4 ohms.
HP was set to ultralinear, to match the
ProLogue Premium.
Some audiophiles hold that at
higher power you may gain maximum
volume but lose some finesse, and that
as long as the amplifier is not driven
into clipping, the fewer the tubes, the
better the sound. Whatever the merits
of this view, it was not confirmed
by this comparison. It would be
overstating things to say that the
DiaLogue Premium HP “blew away”
the ProLogue Premium, but it was
the clear winner. The most obvious
superiority was in the bass. I hadn't
thought of the ProLogue Premium as
being deficient in this department, but
bass in my usual test tracks, such as
“Temple Caves,” from Mickey Hart's
Planet Drum (CD, Rykodisc RCD
10206), extended deeper and was more
solid with the DiaLogue Premium HP.
And while the ProLogue Premium
didn’t seem deficient in allowing
the speakers to project a soundstage,
with the DiaLogue Premium HP the
soundstage was more clearly defined,
and the music generally seemed
to “breathe” with greater dynamic
The tonal balance throughout the
midrange and highs was very similar
through the two amps, the DiaLogue
Premium HP perhaps sounding a
bit more extended at the top. The
ProLogue Premium’s 35 Wpc was
enough to drive the Focals to levels
high enough for me, but my 16' by 14'
by 7.5' listening room doesn’t greatly
challenge a speaker’s room-filling
ability, and while I sometimes listen
at what I like to call “realistic” levels,
I'm by no means a headbanger. The
DiaLogue Premium HP is rated to
produce 70Wpc in ultralinear mode
with EL34s, and up to 85Wpc with
KT120s, thus jestitrine the “HP” in its
name, which PrimaLuna says “stands
for High Power . . . and HeadPhones!”
If you need more power than the
ProLogue Premium, the DiaLogue
Premium HP is ready to provide it.
But what about the triode/ultralinear
comparison? The ProLogue Premium
runs only in ultralinear, so for that amp
the question doesn’t apply. For the
DiaLogue Premium HP, PrimaLuna's
having put the triode/ultralinear
balance ‚лан within 0. 25dB and
the frequency response didn't change.
The DiaLogue Premium obviously
uses a high- uu E for its volume:
Channel Seon ation was adequate
in both directions at and below 1kHz,
at 70dB, but decreased to 44dB (L-R)
band, unweighted signal/noise | ratio
in ultralinear mode, measured at the: 8
“ohm tap with the input shorted but the
volume control set to its maximum,
was okay: 68.6dB left and 69.6dB
right. Hiocen mode improved these ra-
tios by 3dB, and sn ore 7
them to 75.6dB left and 77.7dB right.
Spectral analysis of the noise floor
(not shown) indicated a small level
of 60Hz hum in both channels, due
to magnetic interference from the AC
transformer, but a slightly higher level
of 120Hz in the left channel, at around
‘and 49dB (R-L) at 20kHz. The wide- E
— noise performance for a transformer-
= coupled tube design.
-78dB (0.02%). This is actually good
Figs. 4-7 show how the THD+noise
percentage in the PrimaLuna's output
varied with power with both channels
driven from the 4 ohm tap into 4 ohms
ü 1" 1 |
100m 200m S00m + + 5 40 20 50 400
a | x x L я |
He S50 100 200 500 1K M 5k 10k 20%
tap, ultralinear ee anne (9%) 6 vz
EM oR oer. sE = December 2014
Fig.8 Primalina Dialogue Premium HP, 4 ohm
tap, triode mode, THD+N (96) vs frequency at 4V
into: 8 ohms (left channel blue, right red), 4 ohms
(left cyan, Ei on (gray).
selector button on the remote makes it
easy to make this comparison. I'm not
a fan of comparisons made on the fly,
or switching in the middle of a piece of
music; I prefer to listen to a track all the
Way through (or to the SINE pomt in
the music), then start it again with the
switch in the other position, so that I'm
comparing exactly the same selection
of music.
Staying with EL34s, ultralinear
mode resulted in a sound that was
a little more forward, a bit more
dynamic than triode mode, and
with some recordings seemed to
communicate a greater sense of
excitement. Triode mode sounded
more laid-back, more relaxed. With
my usual test piece of Ana Caram’s
performance of “Viola Fora de Moda,”
from the Chesky Records Jazz Sampler
& Audiophile Test Compact Disc, Vol.1
(CD, Chesky JD37), ultralinear
mode allowed the various percussion
instruments to ring out with greater
clarity. Clark Terry's entrance in
“Pennies from Heaven,” from the same
disc, was more dramatic: again a bit
more forward, triode mode placing his
trumpet a bit deeper in the soundstage.
Which was more “natural,” and
Digital Source Ayre Acoustics
CX-7eMP CD player.
Preamplifier Convergent Audio
Technology SL-1 Renaissance.
Power Amplifier Mcintosh Labs
Integrated Amplifier PrimaLuna
ProLogue Premium.
Loudspeakers Focal Aria 936.
Cables Interconnect, speaker,
AC: Nordost Valhalla 2.
Accessories PS Audio Perfect Wave
Power Plant 5, Nordost Sort Kone
TC, Furutech RD-2 CD demagnetizer.
— Robert Deutsch
which a more accurate representation
of the music as heard in the recording
venue? Search me...I was content
to listen in either mode, most of the
differences being apparent only in
direct comparisons. Forced to choose
between triode and ultralinear, I'd
choose triode —while a little less
dynamic and extended at the extremes,
it had a smooth musicality and an
easy-on-the-ears quality that I found
rs SE
spre " cil m чей
+ am
and from the 8 ohm tap into 8 ohms
with triode and ultralinear modes,
respectively. Primaluna specifies the
maximum output power with EL34
output tubes as 40W into 8 ohms
(16dBW) in triode mode, and 70Wpc
into 8 ohms (18:45dBW) in ultralinear
mode. We define clipping as when the
THD+N in an amplifier's output reach-
es 1%, and these graphs show that
the DiaLogue Premium didn't reach
its specified power at 19% THD+N.
вл in
rw se tpt ee erin pe st te oT RAT pat
ES E e
However, ¡f the clipping definition is
relaxed to 3% THD+N, the amplifier
meets its specified power when the
load is matched to the nominal output-
transformer tap.
These graphs also indicate that the
PrimaLuna amplifier doesn't offer the
lowest distortion, though it remains
between 0.1 and 0.2% at modest
power levels. Figs. 8 and 9, taken at
a level of 4V, which is when the THD
rises above the noise floor, reveal that
20 50 100 200 500 XA Be 10€ 20k
Data in Volts
Fig.9 Primaluna DiaLogue Premium HP, 4 ohm
tap, ultralinear mode, THD+N (9%) vs frequency
at 4V into: 8 ohms (left channel blue, right red), 4
ohms (left cyan, right magenta), 2 ohms (gray). = December 2014
Fig.10 PrimaLuna Dialogue Premium HP. 4 ohm
tap, triode mode, 1kHz waveform at 2W into 4
ohms (top), 0.24% THD+N; distortion and noise
waveform with fundamental notched out (bottom,
not to scale): с
quite beguiling. Of course, with the
DiaLogue Premium HP, triode or
ultralinear is easily selected using the
remote—you can use the mode that
sounds better with a given recording,
or that better suits your mood. My
advice to those not keen on tweaking:
Use triode mode as the default, and
switch to ultralinear only when you
want a bit more oomph.
Tube Rolling
Having satisfied myself that I had a
handle on the sound of the EL34-
equipped Premium HP in triode and
ultralinear modes, it was time to switch
tubes. The KT120 is a more macho
tube, bigger than the EL34; it requires
higher bias, a difference that’s handled
by the DiaLogue's autobias circuitry
and the switch that helps optimize the
bias for tubes in the KT88/KT120
Compared to the EL34s in triode,
the KT120s in triode and at the same
level sounded more dramatic, more
immediately impressive, with voices
more forward—not unlike the EL34s
in ultralinear. With recordings such as
Ariel Ramirez's Misa Criolla, conducted
by José Luis Ocejo (CD, Philips 420
955-2), KT120s/triode had more slam,
with greater dynamic drive. I could
hear why this tube has been winning
adherents. However, on prolonged
listening, switching back and forth
with the EL34s at matched levels, my
ultimate preference was for the EL34.
There was just something right about
the sound of this tube in the DiaLogue
Premium HP. This preference remained
unchanged —in fact, grew stronger—
when I switched the Premium HP
to KT120/ultralinear. In the Gloria
of Misa Criolla, things were fine with
José Carreras's singing, but the choral
voices sounded more homogenized,
more artificial than in triode. In this
selection, the best sound was produced
with the EL34s in triode mode
Finishing Up
The final comparison involved my own
reference combination of Convergent
Audio Technology SL-1 Renaissance
preamplifier ($10,000 with phono
stage, $8000 without) and McIntosh
Labs MC275LE power amp ($6500,
the lowest mid-frequency distortion —
was obtained when the 4 ohm tap
was used to drive 8 ohms, and was
lower in the right channel than the left.
However, the distortion rises at the
frequency extremes, particularly in
the top audio octave, and as the load
impedance drops. These graphs sug-
gest that the 4 ohm tap is best used
with loudspeakers whose impedance
ranges from 4 to 16 ohms, as long as
this tap can provide sufficient gain.
Fortunately, the distortion is heavily
second-harmonic in nature in both
ти кал
cies (fig.11). Peculiarly, in this graph E
‘the low-frequency noise floor is higher
in the right channel than in the left.
Despite its reduced linearity at high
frequencies, the Dialogue Premium
HP performed relatively well on the
demanding high-frequency intermodu-
lation test, with the 1kHz difference
component at an output power of 10W
into 8 ohms typically lying at around
-60dB (0.1%, fig.12).
Overall, the PrimaLuna Dialogue
Premium HP measures well for a
design using push-pull pairs of EL34
modes (fig10), even at low frequen- tubes.—John Atkinson
20 2 29 =
40 40
в 0 в 60
. o
100 100 | |
A20 120 A || | ||
0 200 400 500 BOO 1% ЧР к 10k 15 20k
He Hz
Fig-11 PrimaLuna DiaLogue Premium HP, 8 ohm
tap, triode mode, spectrum of 50Hz sinewave,
DC-1kHz, at 10W into 8 ohms (linear frequency
scale). | « December 2014
Fig.12 PrimaLuna DiaLogue Premium HP, 8
ohm tap, ultralinear mode, HF intermodulation |
spectrum, DC-24kHz, 19+20kHz at 10W peak into |
8 ohms (linear frequency scale).
now available in a Mk.VI version for
$5500). Each is rated Class A in Stereo-
philes “Recommended Components,”
and is widely recognized as a classic.
The CAT SL-1 has a switched-
resistor volume control with fairly
large steps; I first set this at a suitable
level, then matched the DiaLogue
Premium HP to the CAT. Levels thus
matched, and with the DiaLogue
Premium HP in my preferred EL34/
triode mode, the similarities were
more evident than the differences.
Both evinced the smoothness and
musicality that tube aficionados
appreciate, but without the excessive
warmth and rolled-off treble that
characterize some tubed gear.
Background noise was conspicuous
by its absence, and both amps’ power
transformers were quiet.
I heard even more transparency
and detail from the CAT-Mac combo,
but the difference was surprisingly
small—and smaller than the difference
in price might suggest. Dynamics were
comparable, with perhaps just a slight
nod to the CAT-Mac.
Built to a high standard, with some = December 2014
Olaloque Premium HF integrated Amplifier
The amplifier comes
with EL34 tubes as
very useful features—including Adap-
tive AutoBias, Bad Tube indicator,
on-the-fly switching between triode
and ultralinear modes from the remote
control, and headphone output—Pri-
maLuna's DiaLogue Premium HP is
an integrated amplifier whose sound
quality closely approaches that of
pairings of reference Class A preamps
and power amps. The ability to use a
variety of output tubes gives the user
great flexibility in tailoring the sound
to his or her preference. In today's
audio marketplace, $4199 for an inte-
grated amp of the DiaLogue Premium
HP's level of performance represents
excellent value. Primal una has another
winner. m
Was this manual useful for you? yes no
Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Download PDF