Used mostly with Schiit Mani 2, Audio Technica cartridges, Wave Corrector, and KORD DS-DAC-10R

Technics SL-7

Fully automatic;  easy P-mount cartridge swaps in linear tracking arm   back story
Technics dominated the tangential (linear tracking) tonearm turntable market;
their cover-attached tonearm design is vulnerable to airborne microphonics,
but servo-driven tonearms benefit from relatively good damping at the carriage.
Instead of setting up standing waves by reflections from pivots relatively rigid against all but rotation,
arm vibrations transmitted through cartridge from stylus tracing are more quickly absorbed.
Desirable Technics Quartz Direct Drive Automatic Turntable System SL-7 - Tested
eBay item:  266195515624
Condition:  Used
Description:  This listing features a desirable - fully operational - tested by technician -
Technics SL-7 direct drive auto turntable in beautiful cosmetic condition
as well with a round marks on top but otherwise, mint minus.
Plays beautifully, very heavy piece of equipment, will pack safely.


received 7 Apr 2023

Well packed, clean and intact;  plays fine, A-T cartridge emphasizes sibilances,
playing thru Korg AudioGate and DS-DAC-10R.

Audio-Technica and Ortofon P-mount cartridge discussion

LP GEAR Carbon Fidelity T4PSE Spectra Elliptical (CFT4PSE) cartridge

  • Amazon reviews

    ATN3272SLC Latest Nude Special Line Contact for 8008 cartridge

    discussion

    A tracking angle error of no more than 0.1% is claimed, but tracking errors may be less problematic
    than stylus rake angle, which may vary among LP cutters ± 5 from 92 degree ideal.

    Listening tests report that vertical tracking changes of 1/30 of a degree audibly affect music clarity.

    Any number of imagined audible artifacts are associated with tracking and rake angle errors, but:
  • Phono styli cantilevers are relatively short;  small deflections provoke relatively large angle changes.
  • Record warp and tracking force impact rake angle, working against tonearm effective mass and damping.
  • Rake angle error effectively applies box filtering to groove modulations, particularly with line contact styli.
  • Record eccentricity (off-center hole) provokes lateral stylus deflection and dynamic tracking angle error.
  • Tracking angle errors change phase between left and right stereo channels, impacting spatial perception.

    Second-generation Technics linear-tracking turntables included larger SL-DL1 and SL-Q4 models along with the SL-7, with the SL-Q4 sharing SL-7's quartz-phase-lock controlled direct drive platter and boron cantilever.
    Its arm servo control reportedly improved on the original SL-10 linear tracker,
    Technics moving coil cartridge model, offered longer than this second generation, perhaps with updated arm servo?
    The SL-15 had added random track selection programming to the SL-10, while replacing its moving coil with the
    EPC-205C MK3 moving magnet cartridge with ultra low mass stylus, also used in the SL-7 and SL-Q4.
    Gimmicky record clamp disappeared in subsequent generations of LP cover size turntables,
    which shared chassis and covers among models and dropped boron cantilevers.
    That SL-Q4 was a 1 year wonder, being replaced by the well-regarded SL-QL1.
    Weirdly, by 1983 some cheaper linear tracking models (e.g. SL-J11 and SL-L20) were belt-driven.
    By 1986, some cartridges were sourced from Audio Technica.

    Despite general dismissal of Technics linear-tracking turntables by audiophiles,
    many reviewers conceded that they are good at tracking warped records.
    Tracking force by spring instead of mass contributes to low effective tonearm mass, reducing styli vertical excursions. Lack of antiskating force helps lateral alignment, and smaller vertical deflections reduce styli box filtering effects.

    videos

  • restoration
  • arm limit switch, capacitor and mute relay replacement good English caption translation, video details
  • unbox and demo
  • arm not moving - easy fix
  • importance of cover clips
  • motherboard access
  • tracking adjustment VR301

    vinylengine SL-7 articles

    P-mount cartridges

    SL-7 compatible Audio Technica-based T4P premium moving magnet cartridge specifications
    specification (@ 1kHz) AT440E/U CFT4PSE Reference
    Series VML
    Series VL 8008
    freq resp Hz 20-20k 20-20k ?? 12-28k 5-30k
    separation dB 27 18 29
    (18 @ 10 kHz)
    31
    (21 @ 10 kHz)
    Channel Balance dB 0.8 2.0 1.0
    Output mV @ 5cm/sec 4.0 2.5 3 5.0
    VTF gm 1.0-1.8
    (1.4 optimal)
    1.25 ± 0.2 1.0 - 1.5 1.0 - 1.5
    Load Ohms 47k 47k 47k 47k
    Load pF 100-200 100-200 100-200
    Coil DC resistance Ohm 410
    Coil Impedance Ohm 3200 2800
    Coil Inductance mH 490 490
    break-in hours 30
    replacement
    stylus
    LP GEAR
    ATN3472ML
    LP GEAR
    CFNT4PSE
    LP Tunes
    ATNSERIESVL
    ATN3472SLC

    That ATN3472VL stylus may have called the HYPERELLIPTICAL ATN-3472HE with the same .2 x 3 mil tip radii.

    Audio Technica moving magnet cartridge load capacitance

    Many of their moving magnet cartridges are characterized as bright sounding.
    Their 100-200pF typical rated capacitive loading is lower than for other moving magnet cartridges
    and also lower than possible with many phono preamplifiers.
    While one might expect excess capacitance to decrease high frequency response,
    it commonly lowers resonance with cartridge inductance from ultrasonic to audible range:
  • 100pf with 490mH and 37kOhms resonates at 22.7kHz with Q = 1.5;  200pf resonates at 16kHz (150pF at 18.5kHz).
    16kHz resonance increases treble output and brightness, while provoking wild phase shifts.
  • Another cartridge loading calculator with graph

  • 8008 specifications lack both inductance and capacitive load ratings, rather important for claimed 50kHz response..
    Korg DS-DAC-10R specs lack capacitive loading;  if measuring > 100pF, backup plan is Schitt Mani's 47pF loading.
    Many RCA cables included with turntables have capacitance in this range, which adds to preamp capacitive loading.
    Consequently, replacing supplied cables with e.g. RG-59 (often used for component video cables)
    usefully reduces capacitive loading and tames treble response, but 6 ft of even RG-59 adds about 120pF.
    Phono preamps with vacuum tube gain first stages have substantial Miller effect capacitance
    and would be problematic with these cartridges.

    Stylus shapes and dimensions

    alternative premium servo linear tracking direct drive turntables

    The Rabco SL-8 was first linear tracking arm of which I was aware.
    While fascinating, I was already quite disechanted with LP pops and ticks, fully ready to embrace CDs,
    and completely oblivious to Technics' flood of linear trackers, of which the SL-M3 was most highly rated.
    Other premium tangential trackers include B&O's Beograms, and Yamaha PX-1/2/3.
    The B&O MMC-1 is among my favorite cartridges, but having put off retipping it,
    high maintenance Hi-Fi is not for me, and their Beogram 4000 is reputedly quite problematic.
    Few modern cartridges are compatible with Technic's linear tracking turntables,
    but LP GEAR offers better than mediocre P-mount styli, including MicroRidge / MicroLine.
    Support, durability and availability make SL-7 more sensible than a Pioneer PL-L1000 or Yamaha's PX-3:

    Pioneer PL-L1000 "Persnickity to set up and maintain."   AKA Phase Linear 8000
    arm, platter, bearing, and motor on rubber-coated suspension;  highly vulnerable to shipping damage
    Tonearm a bit heavy, tends to lower the resonant frequency.   It needs to be as level as possible.   video
  • low-compliance cartridges will probably work better than super-light MM designs.

  • Pioneer PL-L800
    Polymer Graphite tonearm wand is driven by a direct induction linear motor;  no belts...

    Sony PS-X800 with Linear Biotracer tonearm
    tracking motor ran at a continuous minimum speed while the record played, rather than in small increments.
    Wear in the two tiny belts that link the tracking motors to the arm mechanism is the most common concern.
    Careless platter removal can damage magnetic paint, provoking erratic quartz-lock servo operation.
    --by a wide margin--the finest I've heard among its contemporaneous competitors
    (Technics / Yamaha / Mitsubishi / Revox / Phase Linear / Pioneer)

    Sony PS-X555ES
    Quartz Locked Direct Drive, Biotracer linear tracking arm;  VTA only by shim

    Mitsubishi LT-30
    two arm drive belts, incandescent grain-of-wheat bulbs instead of LEDs

    YAMAHA PX-3
    binding vertical arm ballbearing, 4 belts; main belt irreplaceable, disintegrating feet, unavailable parts

    Audionirvana:  Linear Tracking Tonearms
    mostly air-bearing, except Dereneville DTT
    maintained by blekenbleu