Merrill Audio Jens Phonostage Preamplifier
Jens' incredible micro resolution is the result of vanishing low noise.
Yes Merrill Audio named it Jens, pronounced
origin of this word is Danish. The English translation would be, God
is Gracious. The preamplifier was developed over a period of seven
years by Jens Waale and Beta tested with many audiophile dudes for more than two
years. Merrill Audio has adopted it and improved it further with the guiding
hand of the designer Jens Waale. Now my first question regarding this amplifiers
odd name was answered. However, that was just one of my questions, there will be
many more as this story unfolds during my review of the Merrill Audio Jens
phonostage. For some time this amplifier was only a mere rumor. More than one of
my close New York friends had a go at it while it was in Beta
testing. Finally, the Merrill Audio Jens phonostage has come out of the good
wishes stage and into my hands as a true production product.
The Usual Nomenclature
This is the part where you find out what $15,499 will get you.
The Jens Power Supply and the body of the Phono Preamplifier are housed as two
separate components. Now I asked some very specific questions about what was
inside these two chassis. The reply I received was a brief, "It is solid-state." Therefore, my usual brilliant descriptions of the interior emotive
workings will have to be severely limited. In fact when Editor and Creative Director Steven R. Rochlin asked for high resolution images of the interior,
Merrill Audio was a bit secretive so as not to expose the extreme construction
techniques employed within the Jens. Possible comprehensive circuit related
details involving Op-Amp's, Steam or Windup internal circuits will have to be
omitted. The phono amplifier chassis measures 17" wide by 15" deep by 4"
high and is supported on Stillpoints Ultramini risers. The steel slip case cover
helps shield the Phono stage from electrical interference. It is painted with
metallic gray powder coat enamel.
The phono amplifiers front panel has six blue LED's visible
behind a Plexiglas window. There are three rows one above the other with two
LED's per row. When first powered on all six blue LED's are illuminated. The
Phono stage is designed for continuous operation and has three operating states.
The First State
All three rows, a total of six blue LED's are lit with power on. If there was
something wrong that was detected by the Jens Power supply the six LED's would
remain lit. This also happens when power is turned off, all six blue LED's
will flash on, then off.
Power on with the unbalanced, RCA input ON.
RCA output at this time is not on. When
all internal checks are clear the bottom two rows of LED's are lit. The output
is still not connected to eliminate any pops or clicks.
Input and output are connected internally, middle row of LED's
turns off. This is full operation with only the bottom row containing two blue
LED's remaining on.
At the back, or business side, of the Phono amplifier chassis
are four RCA pure copper rhodium plated jacks made by Furutech and a centered
grounding lug. There is a separate RCA pair for the left and the right channels.
Two are for phono input and another pair for the output to a line preamplifier.
There is provision made for resistive cartridge loading. At the back panel there
are two Ebony wood knobs that may be turned to select one of 12 resistive
loading values. The adjustment range starts at a low value of 5 Ohms and then
progresses through 12 discrete steps and ends with a maximum resistive value of
5000 Ohms. None of the resistive load settings are shown nor are they printed
next to the knobs. I had to double check the loading values with the owner's
manual and count the number of switch detents to double check the cartridges
resistive loading. At this point it becomes obvious that the Jens is made as a
dedicated low output moving coil (MC) phono amplifier.
The performance quality relies on a shielded super quiet power
source. Still no circuit details but I can tell you that the separate power
supply generates 18 volts Direct Current. The Power Supply enclosure measures 7" across the front face and
8" deep and is 4.5" high. The enclosure is
aluminum and painted a light metallic gray. The power supply front panel is made
of a translucent black Plexiglas. At the back panel there is a Schurter double
fused IEC type power cord socket, with on/off switch and a Neutrik Powercon Tru1
locking receptacle for the shielded Umbilical cord. When the power supply is
turned on there are two red LED's visible at the front panel indicating power is
on for both rails. The five foot long Umbilical cord connecting the power supply
to the phono amplifier is shielded and terminated at both ends with Neutrik
Powercon True1 locking connectors.
Now there is a cautionary footnote from the manufacturer. The
owner's manual tells us to place the power supply as far away from the
amplifier chassis as is practical. Not only that but to keep both chassis as far
as possible from any source of EMI and RFI electrical radiation. This is because
sensitive electronic equipment can be effected by electrical radiation in our
environment. And the Jens Amplifier is a very sensitive small signal moving coil
(MC) cartridge amplifier. It has a very respectable 72dB voltage gain, this is an
amplification factor of 3,981. That means that any extraneous electrical
interference may be amplified along with the cartridge signal 3,981 times. So
the preamplifier steel case and the shielded umbilical cord are necessary to
isolate this phono stage from electromagnetic contamination.
A typical 5 microVolt output of a moving magnet cartridge
might be amplified by a factor of roughly 100 (40dB) before the signal is fed to
the rest of the audio system. And a 0.500 microVolt signal from a moving coil
cartridge typically needs to be amplified approximately 1000 times (60dB). Most
cartridges have outputs falling within this range.
The amplification that is required is large when compared to
the very small voltages generated by the cartridges. Therefore any noise entering
the input of the phono stage will be amplified along with the cartridge signals,
as will any noise generated by the amplifier itself. If the amplifier does not
block incoming noise and minimize its own noise contribution, it will bury the
musical signal. The excellent signal to noise ratios should exceed 60dB for a
typical moving magnet (MM) cartridges generating 5mVolts (0.005 Volts). And 70dB
for moving coil devices that generate voltages in the micro Volt range. For
example consider the $6000 Van Den Hul Condor moving coil cartridge which
outputs only 0.00250 parts of one Volt.
A Moving Coil Cartridge From Hell?
Back in May 2012, Enjoy the
Music.com published my review of a very innovative $5000 Haniwa
HCTR01 moving coil cartridge. The HCTR01 is a very low impedance MC (moving
coil) phono cartridge. It is unusual in that it has a very
small internal coil resistance of only 0.8 Ohm and a low inductance
of 1.3uH (micro Henry). Minimizing the HCTR 01 cartridges coil inductance
was the most important design parameter. Inductance my dear Audiopals is
detrimental in that it will alter frequency response and smear phase response.
The specification given for HCTR01 Phase Variance is less than, plus/minus
1%.This is achieved by winding the coil with a bare minimum of wire. It will be
a tough test to get this unusual micro generator cartridge to behave. To
correctly optimize this cartridge and realize its full potential will be beyond
many phono amplifiers. The first problem is to correctly match this cartridge
inductance and internal 0.8 Ohms resistance. Now to approximate a loading value,
follow this old rule of thumb. You look at the coil resistance of the cartridge,
which in this instance is 0.8 Ohms. Now multiply that resistance, in this case
the range should be from 8 to 30 Ohms. We start with the lowest Jens resistance
value of 5 Ohms; that's with the knob indication pointing straight up at 12
o'clock. Then turn one click more in a clockwise direction and the next value
will be 25 Ohms. Listening and switching between these two positions I choose
position #2 at 25 Ohms. At this setting I hear an improved balance between the
bass energy and the treble energy.
To Ear On The Side Of Reality
Let's start with another flea market find, Super
Tramp (live concert) in Paris France, A&M Records [AMP-44001-2].
Let me explain something: I do not use hi quality super vinyl disks to test Tone
Arms, Turntables, Amplifiers or cartridges. The main requirement is that
it is left alone and not faked in the studio. Listening to this concert the live
microphones placement and the sound levels are a mess. The piano is up close and
to the right of center, whilst the vocals are farther back left of center and
the mix is awash in sporadic crowd noise. That's perfect, as the voices in the
crowd and the vocal track shift move within the space between the Alta Audio FRM
2 speakers as reviewed earlier this month. The incredible separation and detail resolution manifested by the
Jens amplifier places you on that stage.
Two weeks after I slotted the Jens into my reference system.
There was a gathering of about 25 audiophiles in the home of one of our members.
The Jens Phono stage was the subject of that meeting. Every one present was
encouraged to bring their favorite vinyl disk. And so over a span of two and a
half hours we listened to a wide variety of vinyl recordings. Each recording was
played twice, first with our host's high-end, high quality phono amplifier and a
second time with the Jens phono amplifier. There was one excellent
recording of operatic aria by Lyric Coloratura Soprano named Aanna Moffo [RCA LSC
2504]. Specifically it is side one, cut one, the Faust opera: Air des bijoux
this stands out as an example of what makes the Jens phono amplifier
Listening with our host's own phono preamplifier in the system
Anna Moffo shifts position and moves about on stage between the speakers. Our
host's phono amplifier places the singer moving from the center front stage then
backward on the stage and then slowly resuming a position, forward stage center.
That very same aria heard through the Jens amplifier depicts the singer's
movements with far more detail. As before the singer stands at the center front
stage then moves farther backward. Now Anna Moffo's position shifts coming from
a different place. ADuring this second playing, the Jens places the Sopranos on
stage position even farther to the back of the stage. In addition her solo voice
has moved farther to the right just next to and slightly behind the right
speaker. Then as before the vocalists position slowly moves forward resuming a
place at the front center stage. This precise stage movement cannot be possible
without exceptional detail resolution and precise imaging.
These entire ultra-low level micro detailing can only be the
result of sonic Dark Matter. The
analogy holds up, it is something that cannot be directly heard or seen but it
exists in the space between every musical note. We know it is there for
how else can there be so many subtle clues in the recording. It is like
listening to the vinyl's mother stamper rather than a copy eight generations
later. It transmits clues of stage dimensionality voice and instrumental
harmonic overtones and even the nature of the space the recording was made within.
Most writers might say a performance with detailing like this is layered over a "black background". But
actually what they are referring to is the component amplifiers noise
floor. This is a type of purity in that the device whatever it may,
be lets the audio signal flow unchanged and unaffected by the power that amplifies
the recorded information. The vanishing low levels of the Merrill Audio Jens
phonostage noise floor showcases why it took so many years, and so many ears, to
perfect this moving coil phono amplifier. In my experience the Jens micro
resolution results from a new vanishing low noise standard. Out of all the many
moving coil amplifiers I have auditioned this one best preserves the original
performance. If you love music and play vinyl recordings with a moving
coil cartridge, then I think you will be impressed. That is only if you care
enough about the myriads of small clues that create a living experience.
Remember to enjoy the music and from me... Semper Hi-Fi.
Review System Components
Source components: Sota Saphier2 turn table and
Haniwa HCTRO 1 Cartridge, Sangean Digital tuner, Marantz 8400 Universal
Music Hall Upsampling DAC 25.3 and headphone amplifier.
Amplification: Sanders ESL power Amplifier, Parasound Halo P5
Preamplifier, ARC SP9 MK3.Tube preamplifier.
Speakers: Alta Audio Celest FRM2, Aurum Cantus Leisure 2
SE two way monitors on 24-inch stands.
Speaker Cables: Kimber Kable 12tc 11ft.
Interconnect Cables: Monster Reference 4 pairs, two-0.5 meter, 1 meter and
meters Nordost Red Dawn, 1meter, Chord Silver Siren 1 meter, Homemade Teflon 1 meter, Autobahn
0.5 meter digital
AC Power: Wire World 10 gauge IEC line cord, Homemade 3 pairs,
12 gauge IEC, Islatrol Industrial 20 amp ac line conditioner, Richard Gray
20 amp Sub Station, Alpha Core Balanced Transformer Power Supply, Audio Power PE-1
power enhancer, Triad 2-ampere isolation transformer
Power Cords: Kaplan Cables
A comfortable chair