Product Details

New LS 100 tube single-ended preamp from ModWright Instruments!

The design goal of the LS 100 was to pick up where the 9.0SE, our first product to be produced, over seven years ago, to the next level. We strove for improved sonics, aesthetics and functionality.

We Succeeded!

Single-ended design with 10 function remote control, (2) 6SN7 (Driver) and (1) 5AR4/GZ34 rectifier. Single gain/buffer stage, phase inverting, five standard inputs, one Monitor input and tape output, one Home Theater Bypass (HT/BP) input and three main sets of RCA outs.

Remote Control Functions Include:

  • Power.
  • Two remote trigger outputs.
  • Selectable balance control, may be bypassed for cleaner signal path.
  • Volume control.
  • Mute.
  • Input select.
  • Monitor input select.


Preamp Functions Include:

  • Upgrade slot for Optional in-board Phono stage.
  • Built in headphone amp fed via tube driver stage.
  • Home Theater Bypass.
  • All pushbutton control, no toggle switches.



  • One pair RCA inputs.
  • Tube Design: (1)12AX7, (1)12AU7
  • MC: Total gain = 63dB (including preamp stage)
  • MM: 12AX7 replaced with 12AU7 = 48dB gain.
  • Loading: 50, 100, 500, 1K, 47K, 100pf via internal dip switches.


The LS 100 is built in the same size enclosure as the KWA 100 amplifier and has the same lines and aesthetics, including backlit logo. Taller enclosure (5”) allows for greater range of rectifier tubes to fit inside the enclosure.

Sonically, the LS 100 offers a greater control, ease, musicality and resolution, all perfectly balanced for the ideal musical experience. Frequency response is flat from 20Hz to well beyond 100Khz. Soundstage is extremely wide and detail and microdynamics co-exist with a tube warmth and natural musical presentation that must be experienced!

Technical Specs

  • Tube Complement: (2) 6SN7 driver tubes; (1) 5AR4 rectifier tube (may also use 5U4GB and 5V4GB).
    Internal tube rectified, solid state regulated power supply.
    Features: Four sets of RCA inputs.
    One set of XLR inputs (wired single-ended).
    Two sets RCA main outputs.
    One set of XLR main outputs (wired single-ended).
    One set of RCA Tape outputs.
    One set of RCA Monitor Inputs.
    One set of RCA Home Theater Bypass (HT/BP) inputs.
    Two 12V remote trigger outputs.
    Gain: 11 dB
    Input Impedance: 38Kohms.
    Output Impedance: 300 ohms.
    Frequency Response: 20hz – 100Khz (+/-1dB).
    Max input signal level: 10 Vrms
    Max output signal level: 37 Vrms
    Headphone Amp Power: 1.5 Watts (32 ohm – 600 ohm load).
    Phono Option: MM/MC (Gain = 48dB/63dB).
    Tube Compliment: (1)12AX7; (1)12AU7.
    Loading: 50, 100, 500, 1K, 47K, 100pf.
    Inputs: One pair RCA.
    Dimensions: 17.75Wx17.5Dx6.5H
    Weight: 25 lbs. (31 lbs. shipped)

Recommended Tube Upgrades for the LS100:

  • Output Tube: Sophia Electric 6SN7 – Sophia Electric
  • Rectifier Tube: Mullard, Amperex or Philips GZ34 Made in Holland.

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