ModWright KWA 99 Monoblock Amplifiers

Plenty of listeners love what Class A sounds like and dread what comes with it: room-heating chassis, huge boxes, and power that runs out on real speakers. Dan Wright built the KWA 99 to answer that. A 100-watt MOSFET monoblock, biased as far toward Class A as practical, in a chassis small enough to sit right next to your speaker.

The short version, the one worth passing along:

Class A sweetness, with the muscle to drive real speakers.

The Design

Each KWA 99 uses Exicon lateral MOSFETs in its output stage. Lateral MOSFETs have a long reputation for a smooth, natural sound and rock-solid thermal stability, which makes them a favorite among designers who want solid-state power with a little of the ease people associate with tubes.

Dan runs those devices in Class A/B with a high Class A bias. Class A is where an amplifier sounds its smoothest, and Dan says the first 30 watts of each KWA 99 run in pure Class A. At sensible volumes, most of your listening happens right there. Stopping short of pure Class A keeps the amps efficient and comfortable to live with, so your listening room stays a listening room. The exposed heatsinks running down each side let the amps hold that high bias with low distortion.

Power is 100 watts into 8 ohms and 200 watts into 4 ohms. That doubling as impedance halves tells you the power supply has real current in reserve, the kind that keeps bass controlled and dynamics effortless on demanding speakers. ModWright has also tested the KWA 99 into 2-ohm loads, where it performs well.

Protection is built in at every level and kept out of the way of the music. The input transformers block DC, internal thermal protection steps in if a chassis ever runs too hot, and ModWright's Total Silent Protection circuit guards against shorts and over-current from outside the signal path. Your speakers stay safe, and the circuitry that sets the sound stays simple.

Both the RCA and XLR inputs are transformer-coupled to the input stage with a floated ground. In practice, the transformer isolates the amp from ground noise coming from the rest of your system, and both inputs get the same clean treatment. Run a balanced preamp or a single-ended one; the KWA 99 makes the most of either.

How It Sounds

Transparency and texture. Those are the two words we keep coming back to. Next to the Unison DMV2, the KWA 99 lights up the midrange and treble, and we mean that in the gentlest sense: a soft white light that brings textures and small details forward while everything stays natural and easy to listen to for hours.

Paired with ModWright's LS 99 preamplifier, the combination steps back and lets each recording's own character define what you hear. Reviewers have heard the same balance of control and finesse across very different speakers, which tells you this amp brings consistency to whatever system it joins.

Connections and Features

• One XLR and one RCA input per amplifier, both transformer-coupled.
• One pair of 5-way binding posts per amplifier.
• 12V trigger input, so the amps power on and off with your preamp. ModWright preamps like the LS 99 bring the whole system up together.
• Amber backlit VU meter with a dimmer knob that takes brightness all the way down to dark.
• Internal LED switch to turn the blue interior lighting on or off.

Where It Fits

At 10.5 inches wide, each KWA 99 fits on a shelf, a stand, or the floor beside its speaker. That lets you keep speaker cables short and run longer interconnects instead, an easy way to get the most from your system. The KWA 99 belongs to ModWright's compact "9" series alongside the LS 99 preamplifier, PH 9.0 phono stage, and Analog Bridge, and it matches them in size and style.

With 26dB of gain and a 47K input impedance, the KWA 99 works happily with virtually any preamplifier. It's a natural partner for the LS 99 and equally at home with the single-ended LS 100. Choose it when you want Class A refinement and real power, and you'd rather have elegant, compact amplifiers than a massive stereo chassis.

Press Recognition

• Twittering Machines (June 2024), Michael Lavorgna, reviewed with the LS 99 preamplifier. Over a two-month stay driving DeVore O/96, Piega, and Audiovector speakers, Lavorgna found the sound remarkably consistent from speaker to speaker: finely resolved and nuanced, natural and rich, and never hyped. Against a Naim stack, he heard more excitement, quicker transients, and more color in timbre. His summary pairs control with delicacy and real drive with timbral rightness. Read the review at Twittering Machines
• Part-Time Audiophile, Pacific Audio Fest 2023 show coverage, Marc Phillips. At the KWA 99's debut, Phillips called the monoblocks the star of the room and singled out the sweetness of the sound, noting it as one of ModWright's finest show rooms. Read the show report at Part-Time Audiophile

Every KWA 99 is designed and handcrafted in Amboy, Washington, and carries a five-year parts and labor warranty when purchased from an authorized ModWright dealer like us.

Curious how the KWA 99 will handle your speakers, or whether it pairs better with the LS 99 or LS 100 in your system? Give us a call. We're happy to work through it with you.

Specifications

• Type: Solid-state monoblock power amplifier (sold as a pair)
• Output devices: Exicon lateral MOSFETs
• Operation: Class A/B with high Class A bias (first 30W pure Class A, per ModWright)
• Power output: 100W into 8 ohms, 200W into 4 ohms
• Gain: 26dB
• Frequency response: 10Hz to 150kHz (+0, -1dB)
• Input impedance: 47k ohms
• Noise floor: -90dB (unweighted)
• THD: less than 0.05%
• Inputs: 1 XLR, 1 RCA, both transformer-coupled to the input stage with floated ground
• Speaker outputs: 1 pair 5-way binding posts (positive red, negative black)
• Trigger: 12V input for remote power on/off
• Display: Amber backlit VU meter with dimmer (adjustable to off)
• Internal lighting: LED on/off switch
• Dimensions (each): 10.5" W x 6.5" H x 16" D overall, including footers and 1" binding posts (chassis 10" W x 6" H x 15" D)
• Weight (each): 30 lbs (35 lbs shipped)
• Finishes: Silver aluminum, black anodized aluminum
• Protection: Transformer-coupled DC input protection, internal thermal protection, TSP (Total Silent Protection) short-circuit and over-current protection outside the signal path
• Load capability: Tested into 2 ohms
• Power: IEC inlet, 120V/60Hz (220V and 240V versions available)
• Warranty: 5 years parts and labor from an authorized dealer, non-transferable
• Designed and handcrafted: Amboy, Washington, USA