Audio Research LS27 Manual Do Utilizador
can be had for 5000 hours. However, he generally recommends replacing the tubes
at somewhere between 4000 and 5000 hours. Replacement tubes cost about
$130/pair.
at somewhere between 4000 and 5000 hours. Replacement tubes cost about
$130/pair.
The LS27 is specified as having a frequency response of 0.2Hz-160kHz, +0/-3dB,
at its rated output (balanced, 200k ohms load), and distortion of less than 0.01% at
2V RMS though its balanced outputs. Its output impedance is 700 ohms balanced,
350 ohms single-ended, 20k ohms minimum load; and the selectable gain for
each input is 18, 12, or 6dB single-ended, and 24, 18, or 12dB balanced.
at its rated output (balanced, 200k ohms load), and distortion of less than 0.01% at
2V RMS though its balanced outputs. Its output impedance is 700 ohms balanced,
350 ohms single-ended, 20k ohms minimum load; and the selectable gain for
each input is 18, 12, or 6dB single-ended, and 24, 18, or 12dB balanced.
According to ARC’s website, the LS27 sounds a lot like the Reference 5, albeit on
a slightly smaller scale. ARC further states that many changes were made between
the LS26 and the LS27, including a new power transformer, new output and bypass
coupling capacitors, a new microprocessor for the function controls, and an improved
power supply.
a slightly smaller scale. ARC further states that many changes were made between
the LS26 and the LS27, including a new power transformer, new output and bypass
coupling capacitors, a new microprocessor for the function controls, and an improved
power supply.
Setup
Setting up a preamp is typically not difficult, and the LS27 was no exception. As with
many tubed products, the LS27’s tubes were delivered uninstalled. Audio Research
inserts them in a protective block of foam, which it tapes to the inside of the
LS27’s case. To install the tubes, you use a heavy-duty Phillips-head screwdriver
(provided) to remove the LS27’s top plate, insert the tubes in their sockets, and
screw the plate back into place. Hook up your signal cables and power cord, and
you’re just about ready to start listening.
many tubed products, the LS27’s tubes were delivered uninstalled. Audio Research
inserts them in a protective block of foam, which it tapes to the inside of the
LS27’s case. To install the tubes, you use a heavy-duty Phillips-head screwdriver
(provided) to remove the LS27’s top plate, insert the tubes in their sockets, and
screw the plate back into place. Hook up your signal cables and power cord, and
you’re just about ready to start listening.
I say “just about” because, for about 50 seconds after startup — or any interruption
of power — the LS27 puts itself in mute mode. After that, it remains muted until you
press the Mute button on the front panel or remote control. According to ARC, this
feature helps protect the LS27 from power interruptions or a severe drop in voltage.
of power — the LS27 puts itself in mute mode. After that, it remains muted until you
press the Mute button on the front panel or remote control. According to ARC, this
feature helps protect the LS27 from power interruptions or a severe drop in voltage.
Even before I received my review sample, ARC sent me a “reviewer’s note” requesting
that I first use the LS27 without a power conditioner, isolation device, or aftermarket
power cord. In some cases, the note said, such products could degrade one or more
aspects of the LS27’s sound. I was also advised that the LS27 requires 100-200
hours of use to be fully broken in, after which it will, according to the note, “continue
to improve incrementally.”
that I first use the LS27 without a power conditioner, isolation device, or aftermarket
power cord. In some cases, the note said, such products could degrade one or more
aspects of the LS27’s sound. I was also advised that the LS27 requires 100-200
hours of use to be fully broken in, after which it will, according to the note, “continue
to improve incrementally.”
Being that my mama didn’t raise no fool, I knew enough to request that the unit
be sent to me with some burn-in time already on it. When it arrived, its tube hour
display informed me that ARC had run it in for about 200 hours.
be sent to me with some burn-in time already on it. When it arrived, its tube hour
display informed me that ARC had run it in for about 200 hours.
I did my initial listening without any of the above-mentioned isolation or AC devices,
and used the power cord provided by ARC. Later, however, after some 100 hours
of listening, I replaced ARC’s stock cord with Synergistic’s Tesla’s T2 cord plugged
into my Synergistic Research Powercell 10SE Mk.II power conditioner, and placed
Synergistic MiG isolation cones under the LS27; the combination of these made
substantial improvements in the sound, with no downsides. So did my Bright Star
Audio Reference isolation platform. From that point on, I used them all.
and used the power cord provided by ARC. Later, however, after some 100 hours
of listening, I replaced ARC’s stock cord with Synergistic’s Tesla’s T2 cord plugged
into my Synergistic Research Powercell 10SE Mk.II power conditioner, and placed
Synergistic MiG isolation cones under the LS27; the combination of these made
substantial improvements in the sound, with no downsides. So did my Bright Star
Audio Reference isolation platform. From that point on, I used them all.
Dave Gordon advises that, for maximum performance in a fully balanced system,
XLR cables be used with the LS27. My system is not balanced, so I used my reference
single-ended cables. Also per ARC’s recommendation, I selected the LS27’s highest
gain setting.
XLR cables be used with the LS27. My system is not balanced, so I used my reference
single-ended cables. Also per ARC’s recommendation, I selected the LS27’s highest
gain setting.
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"...detail was
exceptional."
exceptional."