Modwright KWA 99 Mono Amplifiers

ModWright KWA 99 Monoblock Amplifiers

100 Watts. Maximum Class A Bias. Zero Compromise on What Matters.

Dan Wright's brief for the KWA 99 was specific: a 100-watt MOSFET amplifier, biased as far into Class A as heat rejection and efficiency would allow, in a compact monoblock chassis that fits cleanly into a real listening room. Not an oversized statement piece. Not a pure Class A design that runs hot enough to heat the room. A practical, precisely engineered amplifier that prioritises sound above all else — and then gets out of its own way.

The result is an amplifier that doesn't announce itself. It simply reveals what your system, and your speakers, are actually capable of.

We've run the KWA 99s with the Steinmusic Bobby S Ultimate and the Aurai Z165 — speakers we know well, in rooms we know well. What they did to the bass in both cases was not subtle. We turned the subwoofers off. We didn't need them. What came back was deep, fast, articulate, and tuneful — bass we hadn't heard from either speaker before. No other amplifier has done that in our room.

That's the clearest measure of what a great amplifier actually does: it doesn't add character. It removes the ceiling.

The Design — What Dan Built and Why

The monoblock configuration was a deliberate choice, consistent with the compact '9' series philosophy that runs across the PH 9.0/X/T, Analog Bridge, and LS 99. One chassis per channel means a fully independent power supply for each amplifier, shorter internal signal paths, and complete channel separation from input to output — without the physical footprint of traditional monoblock designs.

Exicon Lateral MOSFETs are the output device of choice. Lateral MOSFETs have long been associated with a particular quality in audio amplification: they run cooler, age more gracefully, and have a current delivery characteristic that some engineers consider more similar to tubes than conventional bipolar transistors. They're not inexpensive, and they're not universal — but they're the right choice for an amplifier designed around sound quality and long-term reliability.

Both RCA and XLR inputs are transformer coupled to the input stage with a floated ground — the same topology that defines the LS 99 preamp. Transformer coupling at the input eliminates ground loop noise, rejects common-mode interference, and ensures the amplifier's input stage is operating with the cleanest possible signal regardless of what's upstream.

Zero global feedback. The KWA 99 does not use feedback to correct errors in the output stage. Whatever the amplifier does, it does without a corrective loop — which places the full burden on the quality of the circuit itself, and removes the phase and transient artifacts that feedback can introduce.

Class A/B operation with high Class A bias. The amplifier operates in Class A for the majority of its output range, crossing into Class B only at higher output levels where the thermal and efficiency trade-offs of pure Class A become impractical. The result is the linearity and naturalness of Class A where it matters most, without the heat and inefficiency that would make the amplifier difficult to live with.

The Listening Experience

The midrange is where the KWA 99 earns its reputation. There is purity here, and dimension, and the kind of musical ease that comes from an amplifier that isn't working hard. Tonal accuracy is excellent — instruments have body and presence without added warmth or coloration. Trailing decays extend naturally into silence. The background is quiet.

The high frequencies are refined and neutral. There is air and space in the upper register, but no edge, no splashiness, nothing that draws attention to itself. Extended but not bright. Present but not forward.

At the frequency extremes, the KWA 99 delivers control rather than spectacle. Bass is not emphasized — it is reproduced with the precision and grip that allows a well-designed speaker to show what it's capable of. At lower listening levels, the high Class A bias means the amplifier maintains its composure and linearity, which is where many designs at this power rating begin to fall apart.

The KWA 99s represent a new level of performance in ModWright's amplifier line. For a company with ModWright's history, that is not a phrase used lightly.

Connectivity and Control

Each monoblock is identically equipped:

• 1× RCA input (transformer coupled)
• 1× XLR balanced input (transformer coupled)
• 1 pair 5-way binding posts (positive red, negative black; not bridged)
• 1× 12V trigger input for system integration
• Analog VU meter with adjustable brightness dimmer (bright, dim, or off)
• Internal LED on/off toggle

The 12V trigger integrates directly with the LS 99 preamp, allowing both amplifiers to power on and off with the preamplifier — a practical detail that matters in daily use.

The amber-illuminated VU meters are not merely aesthetic. They are a functional indicator of output level and a deliberate design choice by Dan Wright — a nod to vintage instrumentation that reflects the amplifier's character: technically modern, but with a warmth and intentionality that connects to the tradition of great amplifier design.

Where the KWA 99 Fits

The KWA 99 Monoblocks are the natural amplification endpoint of a ModWright-based system. Paired with the LS 99 preamp, the two components share transformer-coupled input topology, 12V trigger integration, and a unified design philosophy — a genuinely cohesive balanced stack, not a mix of separately designed pieces.

For systems built around other preamplifiers, the KWA 99s are equally capable partners. The 47K ohm input impedance is accommodating, the balanced input is fully differential, and the gain of 26dB suits the output levels of most modern sources and preamplifiers.

If the speakers you own have been waiting for an amplifier that can show you what they're truly capable of, the KWA 99 is a strong candidate for the one that finally does it.

Press Recognition

Twittering Machines — Favorite Amplifier, June 2024 Michael Lavorgna reviewed the KWA 99 Monoblocks alongside the LS 99 preamp as a complete ModWright balanced stack. Read the review

Specifications

Questions about how the KWA 99s pair with your speakers or fit into your system? We're happy to help you think it through.