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From: cc_s425@ux.kingston.ac.uk (Syngen Brown)
Newsgroups: rec.audio.high-end
Subject: LINGO: Upgrade for Linn LP12
Message-ID: <6739@uwm.edu>
Date: 3 Oct 90 13:07:07 GMT
Sender: news@uwm.edu
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Approved: tjk@csd4.csd.uwm.edu


Someone on this list/mailgroup recently mentioned that there was a new
upgrade for the LP12.  This is the LINGO, an optional replacement for
the Valhalla motor controller.  The following is lifted directly from
Linn's specification release.

  "At the heart of the Lingo are two very low noise crystal oscillators
  derived from the Linn Numerik digital studio recording system - one
  for 33.33rpm and one for 45rpm.  The switch on the turntable selects
  the appropriate oscillator, whose output is fed into a synchronous
  counter to produce a 50Hz or 67.5Hz square wave for 33rpm and 45rpm
  respectively.
  
  As the LP12 motor runs quietest when driven with a clean sinusoidal
  waveform a precision filter is employed in the Lingo to remove
  harmonics from the square wave leaving only a pure sinusoid.
  
  The most uniform torque is delivered from the motor when both phases
  are driven at 90 degrees with respect to one another.  This is
  achieved by a ninety degree phase-shift network after the filter.  The
  two resulting sinusoids adrive two high voltage class A amplifiers,
  the outputs of which drive the two motor windings.
  
  The Lingo uses 'stall detection' circuitry to feed the motor with a
  higher voltage for increased start-up torque.  When the platter
  reaches the selected speed this load-sensing circuitry reduces the
  power output.  From then on the motor just maintains the platter's own
  intertia to keep it going silently.
  
  A toroidal transformer on the PCB, and a mains filter, give a very
  high degree of electrical isolation from the mains voltage supply."
  

The Lingo is housed in a seperate 326x157x75mm enclosure and is
available complete with LP12 or as an upgrade kit.  The Valhalla board
is replaced by a smaller PCB which serves to connect the motor and
switch to the Lingo, via a multiway cable.  The existing (110v) motor
is used and the switch replaced by a dual LED version for speed
changing as per the Linn Axis.  UK prices are quoted at 470 pounds for
the Lingo Power Supply and 26 pounds for the connection kit.  A
complete LP12/Lingo is priced at 1068 pounds.

-Syngen