AUDIOphile,
February'2000
Listening:
Peter Geiger
Technical observations: Johannes Maier
translation
German
Why does a hybrid amplifier, which
interestingly enough operates with both the vacuum tube and
transistors, have to look just as boring as every other US-made
“big sad old piece of artillery”, with the obligatory armor
front panel and lateral heat-sinks? And has the president of Lamm
Industries, Vladimir Shushurin been wise? -- he has bragged for
seven years already, “ I don’t even think about making changes
to our M1.1, there is simply nothing to improve.”
Really? Could the Lamm
Monoblock which I, as a vacuum-tube fan and technician, had just
tested actually endanger the pedigree vacuum-tube products? To be
honest, after the enjoyment of the Lamms it took me days until I
could return to the vacuum-tube models, which are not at all bad.
Comparing the Lamms against the heavily favored adversaries has
developed into a game between Bayern München and some third
division club team.
"Unbelievable,” I said later
as I discussed this with some other Audiophile technicians, “that
such a magic amplifier could be developed”. The technician
grumbled: “it lies in the shocking current power of the M1.1 which
does not fall prey to the short-circuit inducing loads of 1 Ohm.
Or does this mean a renunciation of the negative feedback
(traditionally viewed as all-important), with its considerable
inconsistency within the audio band, leading the ears to be laden
with something that sounds unnatural?
No, said the technicians, Krell,
Levinson, Pass, Rowland and the others already have this reported
technology. At last, others were publishing something similar to
Shushurin’s distortion theories in AUDIOphile’s sister magazine
“Stereoplay” ( “The Cause of the Sound Difference”, number
8/85; Jean Hiraga, from the French L’audiophile), and it took a
considerably long time before Lamm expressed its own views. The idea
that the harmonic waves distribute themselves evenly into all the
modulation frequencies, and behave themselves dynamically correct
according to the motto, “more power, more distortion”, is
therefore old hat.
In designing their products, nobody
was guided by this principle to the degree that this Russians was.
So Lamm’s immense expense in creating the M1.1 has paid off. Each
monoblock possesses eight separate power supplies and a transformer
potted in antivibration-material, which, although it will hardly
ever need to reach such high level of power, can consistently
function at 850 Watts. This also explains the further effort to
assure that the transformer has no mechanical contact with either
the transformer cover or the chassis and introduce a special
circuitry that reduces power transformer core saturation and
mechanical hum. The fact that Shushurin uses exclusive components
from different manufacturers (PRC wirewound resistors, DALE metal
film resistors, ELECTROCUBE and ROEDERSTEIN film capacitors, and
high frequency switching grade CORNELL DUBILIER electrolytic
capacitors) tells us that doing a good job of tuning is what really
mattered.
From this, of course, a most unusual
functioning circuit appears, with a 6922 vacuum tube (also known as
ECC88 professional FM dual triode) located between the ultra-fast
first stage and the driver for the class-A push-pull output stage. Utilization
of the vacuum tube guarantees that nothing and absolutely nothing
has an influence on the sensitive cascading separated transistors.
The DC voltage drifts, thus preventing capacitor coupling between
the front end and the output stage consisting of the twelve output
MOS-FET transistors, and also highlights Shushurin’s intention to
make no more significant changes to this amp.
Thanking the theoreticians for their
contribution, the author--who has heard this amplifier--will now
speak. I freely admit that I am more of a listening-technique-freak.
However, I do not also blindly accept the idea that nobody can offer
conclusive proof of which components of Shushurin’s brilliant
power amplifier provide the special contribution to the magic sound.
Is it the described vacuum-tube stage, or is it perhaps the special
toroidal transformer - with its complex installation, which
mechanically decouples it almost completely from its environment, or
is it hidden details of the complex circuit board design?
It doesn’t matter. Altering
the single sound aspect changes the entire composition and, as a
result, leads to something essential being lost.Only the harmonious
confluence of all the aspects, as each part simultaneously
identifies with itself and its environment, results in the urgency
and credibility of the pertinent sound events.
Hardly had it begun to play, as the
black heavyweights were transformed into something even better –
all their real HiFi ambitions inherent became fully manifest.
Wow, with Jennifer Warnes “Ballad of the Runaway Horse” (on the
Rob Wasserman CD “Duets”) we were both on the verge of tears.
And it was self-evident that the reproduced voice of Diana Krall in
all parts of her “love scenes” could seize the listeners with
its compelling harmony. It possessed power, body, flexibility, and
suppleness; was stimulating, set the air in motion and was erotic.
The pulling of the accompanying bass
indicated as a matter of course the vibration of the strings and the
resonance of the instrument body. The fact makes itself clear that
the bass can reproduce sound of such quality that it seems to be as
fine as my Levinson 333, it also reproduces the piano strokes with
the same energy that one would be able to hear in a live pianist,
and finally reproduces the guitar with the noticeable unique styles
of the guitarist.
The Lamm monos thereby combined the
unbelievable power of Krall’s musical presentation with an ease
and speed, which catapults itself from the head down to the pit of
your stomach.
In interaction of the three
instruments and the singing, everything becomes audible, and this is
what distinguishes the best amplifiers. Also, the listening
experience through the M1.1s was unlike listening through the music
reproduction system – it was close to the listening experience in
the actual recording venue.
Does all this mean that Vladimir
Shushurin has achieved the pinnacle with the M 1.1? No! For
me, there is no best and certainly no perfect part of a Hi-Fi
system, since I have not heard (nor will I ever hear) all the
components in the world. Whoever has the good fortune, and is paid
well enough to be able to afford the artwork of the Russian
American, will answer that question.
Whoever has experienced the listening
enjoyment of the M1.1 will remain faithful to it. And if piety has
something to do with loyalty, then Lamm will work piously.
Conclusion: Unbelievable
emotional and musical hybrid monoblocks; they belong to the very few
best on the world market.
| List of
Best Components in 2/2000 issue of Audiophile magazine:
Lamm
Model M1.1
The hybrid monos shine
not only with the musical character that belongs
to the best tube amplifiers, they also have the authority of the
very few
solid-state power amps.
|
Data and
Measurements
Warranty:
5 years
Dimensions (cm): 43.2 x 21 x 49.5
Weight: 30 kg
Configuration: Hybrid-mono-output Stage
Connection Types: two single-ended (inverted
& non-inverted) inputs,
one balanced (XLR) input, two sets of gold-plated speaker
binding posts (for bi-amping)
Special Loudspeaker Features: Load-selector for
1-6 Ohms or 8-16 Ohms
Topology: Class A Monoblock with a vacuum tube
in the second stage
Build Quality: Professional
Measurements
at a Glance
Continuous
Sinewave Power at 8 Ohm (Pos. 8~16 Ohm) -- 200W
Continuous Sinewave Power at 4 Ohm (Pos. 1~6
Ohm) -- 210W
Rise Time: 8 Ohm/2 Ohm -- 1,9/1,9 uSec
Signal to Noise Ratio: 93dB
Input Impedance: 40 KOhm, 525 pF
|
No load yet has been
complex enough to be able to disturb the Lamm monos. The damping
factor is very linear, and allows neither the load impedance nor
the frequency range (Figure 2) to influence the measurements taken
at 2-Ohm-load resistance. The load switch for the two sets of
loads: from 1 to 6 Ohms and 8 to 16 Ohms respectively; this feature
is equivalent to using the matching output transformer, which
additionally ensures safe operation and prevent thermal
overload during peak performance and allows to deliver a musical
signal of the Lamms end stage without problems at 600 Watts/2 Ohms.
The fact that the M1.1 has a hybrid construction with a driving
vacuum tube is obvious from the typical spectrum of 1 kHz sinewave.
Fig. 1.
Voltage-impedance plot (Pos. 1~6 Ohms)
fig. 2. Frequency
response
Fig. 3. Distortion
spectrum (1 kHz, 10V, 4 Ohms)
[captions under
photographs-- not reproduced here]
1.A
wolf in a Lamm’s clothing: This seven-year-old amplifier which
has not undergone significant changes and designed in accordance
with distortion theories has a lot packed into it, and is here to
stay
2. Heat:
The small heatsinks in the vicinity of the vacuum tube silently
cool off the driving transistors. Powerful aluminum heatsinks
divert the heat of the twelve powerful output transistors.
M1.2
Reference
