Jadis JA80 MkII - Absolute Sounds
Monoblock tube power amplifier. Rated at 80W/4ohm
Made by: Jadis S.A.R.L, France
Supplied by: Absolute Sounds Ltd
Telephone: 0208 971 3909
Web: www.jadis-electronics.com; www.absolutesounds.com
Price: £7998 (each)
POWER AMPLIFIER
Jadis JA80 MkII
Hand-built with point-to-point wiring, as it’s been since 1983, the French specialist’s
very first power amplifier design will now accommodate today’s more powerful tubes
Review: Steve Harris Lab: Paul Miller
N
amed after an old French word
meaning ‘long ago’, Jadis took
off on the first tube amp revival
wave nearly 35 years ago, and
has stayed true to the cause ever since.
In fact, the JA80 MkII monoblock, priced
at £7998 per channel, is an updated
version of the company’s very first product.
When the original JA80 was launched back
in 1983, tube supplies were dwindling
and there was relatively little choice of
valve types. Jadis founder André Calmettes
based his JA80 output stage around the
KT88 beam tetrode and its American nearequivalent, the 6550.
pure class a
Jadis has never set out to extract the
maximum power from a given set of tubes,
but has aimed for the best sound quality.
Like almost all its designs, the JA80 is run
in pure Class A, which means that the two
tubes in a push-pull pair are conducting
all the time, and this in turn means lower
BELOW: Hand-soldered, point-to-point wiring
is a theme of all Jadis amplifiers. Note the
busbar links (centre), configuring the output
transformer here to 4ohm (1-16ohm is possible)
efficiency and limited power output. So
although the JA80 used two pairs of KT88s
in parallel, rated output was still only 60W.
Since the 1980s, with a strong revival of
tube manufacturing, mainly driven by the
guitar amp market but also feeding into
specialist hi-fi, we’ve seen new tubes that
not only replace the KT88 but also offer
more power. First came the KT90 from
Serbia, then the Russian-made Tung-Sol
KT120, which could be used with the JA80.
In its MkII form, the JA80
also becomes compatible
with Tung-Sol’s latest
and most powerful ‘KT’
tube. This is the KT150,
identified by its egg-shaped
glass envelope, which is
said to reduce or eliminate
microphony. You can
choose to use KT120, KT90, KT88, 6550,
6CA7 or EL34s instead, but a change of
tubes will require an internal modification
by the factory or a Jadis agent. But tube
choice is largely a matter of personal taste,
as much as power output.
Jadis now offers a very wide range of
amplifiers, from the gigantic JA800 down
to the entry-level JA15 monoblock. Though
it’s far from being the biggest model, the
JA80 MkII’s shoebox layout and harmonious
physical proportions make it seem the
epitome of classic valve amp design, with a
look that combines functionalism with the
bling of chrome and gold.
On display at one end of the chassis –
under the sturdy black mesh safety cover
– are the tubes. In front of the four curvy
KT150 tubes are two small double-triode
tubes, an ECC82 for the driver stage
and an ECC83, which
is the phase splitter.
Also seen reflected
in the immaculate
chrome surface are the
coupling capacitors for
these stages. Hidden
underneath this section
of the chassis, the
whole amplifier circuit is executed in
hand-soldered point-to-point wiring,
with components attached to the nest
of connecting bars that run between the
valve bases [see inside picture, below].
On the outside, the signal connections
are simple and direct, just a single RCA
phono input sited as close as possible to
the ECC82, and two pairs of 4mm socket/
‘The JA80 MkII
really brought
out the passion
in the playing’
REPRODUCED FROM HI-FI NEWS | www.hifinews.co.uk
060-063 Jadis JA80mkII_v9_CBPMPFSP.indd 60
3/14/17 10:46:07 AM
binding posts to cater for the
option of speaker bi-wiring.
At the other end of the amplifier there
is no attempt to disguise the outline of
the mains transformer, but it’s beautified
with a superbly chromed top cover. In
the middle, with the impressive gold Jadis
nameplate, is the box that contains the
output transformer. This is made in-house
at Jadis and its special design is really the
key to the amplifier’s success.
You can set the transformer’s output
connections to match speaker impedances
from 1 to 16ohm, but this has to be
done by removing the bottom cover and
re-configuring a Meccano-like array of
connecting strips. In practice, the default
setting should be fine for conventional 4 to
8ohm speakers [see PM’s Lab Report, p63].
amp for the enthusiast
In handling and operation, the JA80 MkII
is still essentially an old-school enthusiast’s
amplifier, rather than a sanitised, ‘tubes
without tears’ type. It does have automatic
bias, so there are no bias-setting controls
to fiddle with, but it doesn’t use a lot of
technology or modern peripheral control
circuits to make it foolproof. For example,
ABOVE: Controls are simple. First switch on
the mains at the left, then allow a few minutes’
warm-up before moving the right-hand switch
from Standby to Operate
Jadis warns that the preamplifier in your
system should be switched on first, and
having taken this precaution, switching
on the JA80 MkII is a two-step process.
On the front panel, the left-hand toggle is
the main power switch, which takes the
unit from Off to Standby mode, meaning
that current can now flow to the heater
filaments in the tubes.
Each power tube has a fuse and an
indicator LED next to it. If an LED glows
red, the fuse has blown and the tube is
probably faulty, which means a call to
your Jadis dealer. ‘To ensure long-term
reliability,’ the instruction manual warns,
‘the On/Off power switch must be operated
with a quick firm movement.’ When you flip
this switch, you are making the electrical
connection directly, not initiating an
electronically-controlled relay operation.
It’s advised that you should leave the
amplifier in standby for five or ten minutes
FAMILY AFFAIR
Very much a family business, Jadis is still located in the small village of
Villedubert in the far south of France, where it got started in 1983. Founder
André Calmettes was a cabinetmaker but also a keen radio amateur and a selftaught electronics hobbyist. After his first home-built tube amp had impressed
friends and neighbours, he was persuaded to show it to an audio distributor in
Paris. Calmettes teamed up with Jean-Paul Caffi, then working in pharmaceutical
sales, and the brand was born. Soon Jadis was exporting to many countries, but
especially the Far East. Today the managing director is André Calmettes’ son
Patrick, who’d been involved in the company from the beginning and took over
when his father retired. Patrick’s son Jean-Christophe joined the company in
1993 and is now technical director. Since Caffi’s withdrawal from the company,
the third key member of the team has been Liliane Expert, an experienced
businesswoman in real estate and with a long-term interest in the company.
to allow the tubes to warm up, before
moving the right-hand toggle switch from
Standby to Operate. Now the high-tension
power supply to the tubes will turn on, the
fascia’s central LED will change from red to
green, and the music can begin.
an organic flow
The first music that I heard through these
JA80 MkIIs was a Beethoven string quartet,
from the Paris recordings by the Hungarian
Quartet [Les Quatuors À Cordes; EMI
France, CZS 7 67236 2]. These 1953 mono
recordings naturally lack the theoretical
dynamic range and extended frequency
response of a modern studio offering, and
can sound rather boxed-in. But with the
JA80 MkII there was a great strength and
realism to the middle range string sounds.
The flow of the music was simply organic.
Back in the early 1990s, when I told
Ashley James of AVI that I was trying to
collect the original HMV LPs, he very kindly
sent me the 7CD box set as a gift. I’d been
enjoying this ever since, but listening again
via the JA80 MkII made me appreciate
anew both the musical power of the
original recordings and the integrity of
the CD transfers. They sounded, dare I say
it, more analogue than ever, but I found
myself forgetting about such distinctions as
I was carried away by the performances.
Then I put on some music that needs to
be turned up loud, ‘Blues For Klook’ from
Sang Melé by French Hammond organist
Eddy Louiss [Nocturne NTCD101]. This
late-’80s hi-fi dem favourite was introduced
to UK ears by Ricardo Franassovici of
Absolute Sounds, long-term distributor
of Jadis! Electric keyboards can sound
cold and impersonal, but in this heartfelt
www.hifinews.co.uk | REPRODUCED FROM HI-FI NEWS
060-063 Jadis JA80mkII_v9_CBPMPFSP.indd 61
3/14/17 10:46:15 AM
Lab
report
Jadis JA80 mkII
LEFT: Pairs
of KT150s
exposed with the cage
removed. One RCA input
and bi-wire speaker connections
are fitted (impedance set internally)
performance by Louiss there’s never
any danger of that. And the JA80
MkII really brought out the passion
in the playing, the poignant lyrical
feel of the swooping sounds Louiss
employs in this elegiac minor-key
blues. At the famous moment when
a deep bass part starts, the JA80
MkII didn’t disappoint, because
the bass sound was full-bodied and
dramatic, albeit – unsurprisingly –
without the gut-wrenching slam you
could get from a big solid-state amp.
palpable spaces
In fact, with synthesiser-based music
generally, the Jadis seemed able to
soften and humanise the electronica
in a very appealing way. With the
title track from Simple Minds’ Cry
[Eagle EAGSACD196], the JA80 MkII
drew you in to the vortex of synth
sounds that seem to swirl in three
dimensions as the track builds to
a climax. Perhaps you would not
choose the JA80 MkII for this music
if your main aim was to bring out
bottom end power, but with this
amplifier the Scottish superband’s
rhythms were hypnotic nonetheless.
On classic rock tracks, the JA80
MkII could provide a well rounded,
even slightly softened quality that
could welcome you in to the music.
Putting on Blood On The Tracks
[Columbia 512350 6], those rhythm
guitars in ‘Tangled Up In Blue’ were
insistent but not remorselessly
aggressive, while ‘Simple Twist Of
Fate’ was spacious, relaxed and
poignant. That’s not to say the
sound was lacking in insight or detail
though, as the JA80 MkII clearly
revealed the little artifices of studio
reverb that give Dylan’s vocal a lift
at the ends of lines.
If you feel that female vocals
provide the acid test of any
component or system, you might
want to know that the JA80 MkII
excelled in this department. I put
on an old favourite: Rosa Passos
with her 2008 album Rosa [Telarc
CD-83646]. Here you have just
voice and guitar, as the singer
accompanies herself in a very welljudged studio acoustic, and the JA80
MkII made the most of it, that lovely
youthful-yet-worldly voice presented
intimately, yet with air round it as
she caressed her lyrics into life. Her
guitar sounded truly full-bodied and
sonorous too as she fingered those
beautiful Brazilian chords.
Returning to classical music
and some favourite orchestral
recordings, I found that the JA80
MkII really could give you a big,
wide and gloriously laid-back
soundstage, with a palpable sense
of space and depth. On ‘The Great
Gate Of Kiev’ from the Mussorgsky/
Ravel Pictures At An Exhibition
[Reference Recordings RR-79] the
Minnesota Orchestra sounded both
measured and sonorous, with the
big bass-drum weighty enough to
be convincing in a presentation that
was truly enthralling.
As we saw with the I-50 integrated, which afforded just 50W/
4ohm at 3% THD [HFN Apr ’15], Jadis’s Class A push-pull
configuration does not aim to squeeze the maximum output
from its KT150 tubes. Indeed, Audio Research musters
80W/4ohm from its GSi75 [HFN Jan ’16] while Icon Audio’s
MB90 MkIIm-150 achieves 120W/4ohm from a single pair
of these tubes [HFN Mar ’14]. And so it is with the JA80 MkII
which, with no fewer than two pairs of KT150s per monoblock,
delivers just 90W/8ohm and 120W/4ohm/1% THD (our JA80
mkII was configured for 4ohm – see inside shot, p60). But
no-one should be considering this boutique beauty on the basis
of Jadis’s spec. for even the rated max. power consumption of
200W is closer to 300W in practice (idle or full output)...
Under dynamic conditions the JA80 MkII realises a similar
86W, 118W, 134W and 66W into 8, 4, 2 and 1ohm loads
[see Graph 1, below]. The amp is clearly best partnered with
sensitive speakers, for while its response is good to within
±0.3dB over the 20Hz-20kHz audio range (and only mildly
influenced by the ~0.24ohm output impedance), its distortion
is much lower at lower output. CCIR intermodulation, for
example, increases from just 0.06% at 1W/4ohm to 0.2%/5W
and 1%/10W while harmonic distortion rises from ~0.015%/1W
to ~0.05%/10W and 0.45%/80W at midrange frequencies. The
increase in distortion at bass/treble frequency extremes is more
pronounced: from 0.05%/1W to 0.25%/10W at 20Hz and from
0.13%/1W to 12%/10W at 20kHz – so coloration will likely be
more apparent at high treble frequencies [see Graph 2, below].
Noise, too, is a little high, the A-wtd S/N ratio clocking in at just
78dB (re. 0dBW). PM
ABOVE: Dynamic power output versus distortion into
8ohm (black trace), 4ohm (red), 2ohm (blue) and
1ohm (green) loads. Maximum current is 8.1A
HI-FI NEWS VERDICT
Updated in terms of tube choice,
the JA80 MkII version remains the
deliberately traditional product it
always was. It sounds delightful,
smoothly inviting in the treble
and well balanced within its own
compass, adding a touch of its
own character, pleasing rather
than revelatory, but never warm
’n’ woolly. Its great strength is the
musical coherence it provides. It’s
expensive considering the power
output on offer, but who cares?
Sound Quality: 84%
0
-
-
-
-
-
-
-
- 100
ABOVE: Distortion vs. frequency, 5Hz-40kHz at 1W/
8ohm (black) and 20Hz-20kHz at 10W/8ohm (red)
HI-FI NEWS SPECIFICATIONS
Power output (<1% THD, 8/4ohm)
90W / 120W (4ohm tap)
Dynamic power (<1% THD, 8/4/2/1ohm)
86W / 118W / 134W / 66W
Output impedance (20Hz–20kHz)
0.235-0.250ohm
Freq. resp. (20Hz-20kHz/100kHz)
+0.01dB to –0.30dB/–7.3dB
Input sensitivity (for 0dBW/80W)
89mV / 815mV
A-wtd S/N ratio (re. 0dBW/80W)
77.8dB / 96.8dB
Distortion (20Hz-20kHz, 10W/8ohm)
0.050-12%
Power consumption (Idle/Rated o/p)
299W / 321W (85W standby)
Dimensions (WHD) / Weight
260x240x625mm / 35kg (each)
www.hifinews.co.uk | REPRODUCED FROM HI-FI NEWS
060-063 Jadis JA80mkII_v9_CBPMPFSP.indd 63
3/14/17 10:46:20 AM
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

advertising