In the room illusion
Listening to Jacqueline du Pré and Daniel
Barenboim performing the two Brahms cello sonatas (EMI CDM 7 63298 2) showed
immediately that this combo makes for a delightful pairing, the cello’s dusky
woodiness being reproduced with vivid presence and speciousness. The imaging
was as good as I’ve ever experienced in my listening room – the sense of two
instruments ‘hanging in the air’, cello slightly in front of piano, was
uncanny. Furthermore, the piano was reproduced with convincingly percussive
attack and decay, the Jazz/MSA creating a rock-solid sonic picture with
commendable precision.
The sound is exceptionally clear and crisp
at high frequencies. The shimmer of cymbals as their reverberation tails decay
to silence took my breath away as I listened to a selection of purist
audiophile recordings, in order to assess the Nagra’s capabilities. My resident
Levinson No.383 integrated couldn’t hold a candle to it in terms of
transparency and HF detail retrieval.
I’d been captivated from the outset, but
was blown away by the sense of spatial realism the Nagra combo delivered, and
the ‘cleanliness’ of the sound, especially when playing New York-based
guitarist Stew Culter’s ‘Lovely Mary’ from his album Insignia (naimcd05 on CD;
alternatively available as a 24-bit/96kHz download).
Inside
the MSA power amplifier (seem from below), Nagra’s dual-mnono layout is clearly
revealed as are the separate L/R switchmode PSUs with PFC (Power Factor
Correction). The pairs of output MOSFETs are bolted to the underside of the
heatsink that ‘crowns’ the MSA
Nagra all the way
I had spoken recently with Ken Christianson
of Chicago specialist audio dealer Pro Musica, who engineered the album in a
simple, minimalist fashion that he calls True Stereo, capturing live takes of
Cutler performing with fellow musicians Booker King (bass) and Garry Bruer
(drums).
Christianson told me that he recorded
Insignia back in 2001 using a Nagra IV-S analogue tape machine running at
7.5ips, and more recently created the hi-res digital version using the
converters of a NAgra VI digital recorder. The purity of the sound – the
lifelike dynamics and naturalness of the percussion in particular speaks
volumes for the transparency and top-notch detail retrieval of Nagra’s
electronics, and this shining example of how to capture a musical trio performing
in an acoustic space was served up wonderfully by the Jazz preamp and MSA power
amp driving my Townshend Sir Galahad loudspeakers.
My computer audio source currently feeds a
T+A DAC 8 which can also be used as a preamp, so I experimented in removing the
Jazz from the replay chain and fed the DAC’s balanced outputs directly into the
MSA power amplifier. The natural openness and clarity of the treble remained,
as did the speed and lightness of touch. Recalling the sound of Nagra’s 300i
amplifier that I had so enjoyed at the end of 2011, I’m frankly amazed that
Nagra can engineer two such disparate amplifier designs – its 300i employing
300B direct heated triodes, this MSA using MOSFETs – yet maintain a striking
family resemblance in tonality and resolution.
The sound of the MSA is a little more stark
and ‘dry’, however. I observed some leanness in the upper bass/lower mid that
creates a slight ‘greying’ a bleaching, if you like of color and warmth in the
MSA that appears ameliorated when used in unison with the Jazz preamp. As a
combination, the pre/power is beautifully balanced.
The
MSA power amp offers a 1 or 2V input sensitivity through balanced XLRs and
bridged mono operation through floating outputs
I found myself ‘progging out’ to Steve
Hackett and Chris Squire’s collaboration A Life Within A Day released a few
months ago (Esoteric Antenna EANTCD 21002). Naturally the album is riddled with
progressive rock clichés what else might we expect from the guitarist of
Genesis and bassist of Yes? - nevertheless the structure and melody of the
track ‘Tall Ships’ is sublime in my book, replete with enchanting Crosby,
Stills & Nash-style tight harmony vocals and achingly beautiful sustained
guitar licks.
Typical of the genre the production is
rather dense, yet the Nagra proved tremendous at peeling through the blanket
layers of the mix and creating space, Squire’s fat and characteristically
Twangy bass riff patterns underpinning the myriad keyboard, guitar and
reverberant vocal lines.
The
Jazz includes five line inputs, a bypass, two RCA and one balanced XLR output
VFS isolation base
Isolating electronics from external
vibration can pay dividends in terms of image clarity and focus, so I also
experimented with one of Nagra’s Vibration Free Support isolation bases – seen
underneath the Jazz preamp in our photographs.
Recently reduced from $2,137.5 to $1,935,
the VFS was designed by the company for its tubed phono stages, but since all
Nagra components have the same footprint it can be used universally. The ‘kit’
comprises three inverted cone alloy feet with Delrin tips (these are available
separately as a set for $360) and two 7mm thick aluminum plates that have Alpha
GEL shock absorbers underneath for decoupling. I can’t claim to have heard a
sonic improvement with the VFS underneath the MSA power amp, but it did enhance
the performance of the Jazz.
The verdict
It’s hard to criticize the open and vivid
sound. These components are also beautifully built and lovely to use. Only if
your speakers are lean in the bass and a little ‘sharp’ will you crave
amplification with a more creamy and rich tonal character. Audiophiles looking
for high-end performance in a jewel-like package should certainly hear the new
Jazz preamp and in combination with the MSA.
Sound quality: 8.3/10
Lab report
Nagra Jazz/ MSA
On test, the Jazz preamp’s 0dB/+12dB gain
settings actually amounted to -6.3dB/ +5.7dB via its balanced connections as
the XLR input is not truly balanced unless you order the optional input
transformers. So, add 6dB to my figures and you get the requisite 0dB/ +12dB
gain. The 0dB Modulometer setting is precisely mapped to a 1V output (up to 6V
out is achievable) through a modest 75ohm source impedance, rising to 130ohm at
20Hz (or 97-150ohm in +12dB mode). This rise only influences the extreme LF
response in the 0dB setting which, while flat to -0.75dB/ 100kHz, also has a
subsonic boost of +0.7dB/ 5Hz and +6dB/2 Hz. The response at +12dB gain is
imperceptibly more rolled-off at HF (-0.35dB vs. -0.2dB/ 20kHz) but the bass
end rolls steeply away below 3Hz. Distortion not only increases at very low and
high frequencies, as expected, but also depends on gain, increasing from 0.006%
at 100mV to 0.5% at 6V output.
Graph 2 also illustrates how the ECC81/
83-based Jazz is well-matched to the MOSFET/ switch mode PSU-based MSA, both
having similar THD characteristics despite their differing technologies. The
MSA exceeds Nagra’s 60W spec. at 2x69W/8ohm but the stiff regulation of the PSU
means there’s little headroom beyond 70W, 120W and 170W into 8, 4 and 2ohm
loads. Noise is exceptionally low, the A-wtd S/N ratio a wide 92dB re. 0dBW,
while the response is flat to -0.3dB (20Hz-20 kHz) and the output impedance
good to 0.075ohm.
Dynamic
power output versus distortion into 8ohm (black trace), 4ohm (red), 2ohm (blue)
and 1ohm (green) speaker loads
THD
vs. extended frequency; Jazz (1V out/+12dB gain, black trace) vs. MSA
(10W/8ohm, blue)
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Specifications
§ Price:
Jazz, $13125/ MSA, $9675
§ Power
output (<1% THD, 8/4ohm): 69W / 103W
§ Dynamic
power (<1% THD, 8/4/2/1ohm): 70W / 122W / 170W / 170W
§ Output
imp. (20Hz-20kHz, pre/power): 150-97ohm / 0.075-0.13ohm
§ Freq.
resp. (20Hz-100kHz, pre/power): +0.0 to -1.4dB / -0.1 to -4.9dB
§ Input
sensitivity (for 0dBV/0dBW): 520mV (pre) / 130mV (power)
§ wtd
S/N ratio (re. 0dB/0dBW): 93.7dB (pre) / 91.5dB (power)
§ Distortion
(20Hz-20kHz, 1v/10W): 0.055-0.35% / 0.045-0.70%
§ Power
Consump. (pre/idle/rated o/p): 17W/19W/211W
§ Dimensions
(HWD):310x254x76 /280x230x118mm
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