ModWright LS 300 Balanced Tube Preamplifier

The LS 300 is Dan Wright's reference preamplifier, the design every other ModWright preamp is measured against. It's where his years of work with fully balanced circuits, 6922 tubes, and Lundahl transformers come together in one uncompromised two-box design. ModWright's own goal for it: the beauty of tubes, with a neutral voice that lets the music flow straight through.

Here's the idea in a sentence:

Each channel, its own power supply. That's the flagship difference.

The Design

The LS 300 is dual mono from the power supply forward. The outboard supply builds two complete, independent supplies, one per channel, each with its own 5R4GY tube rectifier, choke-input filtering, and discrete FET regulation. Two separate umbilicals carry that power to the preamp. Left and right share a chassis and nothing else, and that independence is what gives the LS 300 its wide, stable soundstage and clean separation between instruments.

The gain stage uses two 6922 tubes running in pure Class A with zero negative feedback, fully balanced from input to output. Swedish Lundahl transformers couple the signal in and out, and every RCA input passes through a Lundahl transformer that converts it to a balanced signal. Your single-ended sources get the same fully balanced treatment as your XLR ones.

ModWright rates the noise floor at -115dB, quieter still than the LS 99's -110dB. Quiet like that lets low-level detail and the decay of notes come through untouched.

Thoughtful touches round it out. A motorized Alps volume control works from the remote, a soft-start sequence brings the high voltage up gently while the preamp mutes for about 45 seconds, and a switch on the supply lets you lift the ground if your system ever develops hum. Give it 30 to 45 minutes after power-up and it settles into its best sound.

How It Sounds

Next to the LS 99, the LS 300 digs deeper into the music. We hear more resolution, more of the fine detail living inside each recording, and it arrives with a warmer, sweetly lush presentation. More information and more warmth at the same time is a rare combination, and it's the reason to step up to the flagship.

That matches what ModWright set out to build: bold, refined tonal balance with deep, tight bass, highs that sparkle, and detail free of edge or glare, carried on the liquidity and three-dimensional imaging of tubes.

Dan Wright puts the LS 99 at about 95% of the LS 300's sound. The fully dual mono supply, the second rectifier, and the even lower noise floor account for that last stretch, and it's exactly where we hear the difference: deeper detail and a richer, more generous tone.

Connections and Controls

• Two fully balanced XLR inputs.
• Three RCA inputs, each converted to balanced through Lundahl transformers. One doubles as the Home Theater Bypass input.
• Two fully balanced XLR outputs and two RCA outputs.
• Front-panel input selector, volume, power, mute, Home Theater Bypass, and phase controls.
• Remote control for volume, mute, power, and absolute phase. The LS 300 starts up phase-correct.
• Rear ground switch to choose fully balanced XLR operation, or RCA and XLR outputs at the same time for a subwoofer or second amplifier.

Where It Fits

ModWright designed the LS 300 to partner with its reference amplifiers, and it's at home at the center of a fully balanced system at any level. Its two balanced outputs make bi-amping or adding a subwoofer simple.

Choose the LS 300 when you want the complete ModWright reference experience and your system can reveal it. If space or budget points you to something more compact, the LS 99 carries the same transformer-coupled circuit in a smaller chassis, and the two share the same sonic family.

Home Theater Bypass sends your processor's front channels straight to the main outputs at the processor's volume setting, and the path stays open even with the LS 300 switched off. Connect only a processor or source with its own volume control to this input.

Every LS 300 is designed and handcrafted in Amboy, Washington, and carries a five-year warranty when purchased from an authorized ModWright dealer like us, with tubes covered for three months.

Press Recognition

• Stereophile, SouthWest Audio Fest 2026 show coverage. In ModWright's room, the LS 300 drove the new KWA 300 amplifier into Alta Audio speakers. Stereophile described a warm, sweetly lush sound with layered synths beautifully separated in space, and gave the room a thumbs-up. Read the show report at Stereophile

Deciding between the LS 300 and the LS 99, or wondering how the flagship will suit your amplifier? Give us a call. We'll walk through it with you.

Specifications

• Type: Fully balanced, dual mono tube preamplifier, two-chassis design
• Gain stage: Pure Class A, zero negative feedback, Lundahl transformer-coupled input and output
• Tube complement: 2 x 6922/6DJ8/7308 (drivers), 2 x 5R4GY (rectifiers)
• Rectifier substitutions: 5AR4/GZ34, 5U4GB, 5V4GB, 274B and equivalents
• Power supply: Outboard, fully dual mono, tube rectified, choke input, discrete FET regulated B+, regulated DC heaters, soft-start
• Gain: 11dB
• Frequency response: 20Hz to 100kHz (-1dB at 100kHz)
• Distortion: less than 0.03% THD at 1kHz
• Noise: -115dB
• Input impedance: 20k ohms
• Output impedance: 100 ohms
• Inputs: 2 pairs XLR (fully balanced), 3 pairs RCA (one doubles as Home Theater Bypass)
• Outputs: 2 pairs XLR (fully balanced), 2 pairs RCA
• Volume control: Motorized Alps potentiometer
• Front panel: Input select, volume, power, mute, Home Theater Bypass, phase
• Remote control: Volume, mute, power, absolute phase
• Dimensions, preamp: 17" W x 8" H x 12.5" D (height depends on rectifier tube)
• Dimensions, power supply: 8" W x 4.5" H x 10" D
• Weight: Preamp 30 lbs, power supply 17 lbs
• Umbilicals: 2 x 4 ft, 8-pin Switchcraft connectors
• Power: IEC inlet, 120V/60Hz standard
• Warranty: 5 years from an authorized dealer, tubes 3 months, non-transferable
• Designed and handcrafted: Amboy, Washington, USA