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ModWright Instruments, 21919 NE 399th Street, Amboy, WA (2026)

09/17/2026

Power Supplies ARE Part of the Signal Path

Power supply design is one of the most important parts of any audio design. What people may not realize is that, in a very real sense, the power supply is part of the signal path.

An audio circuit is essentially translating power from the power supply into an audio signal. A power amplifier makes this particularly easy to understand: the energy delivered to the loudspeaker ultimately comes from the power supply. The audio circuitry controls that energy according to the incoming signal.

Tube and solid-state circuits approach this differently. Tube circuits tend to operate with relatively high voltages and lower currents, while solid-state power amplifiers generally operate at much lower voltages and considerably higher currents. Either way, that voltage and current originate in the power supply.

So what does a good power supply need to do?

It must provide sufficient current without becoming a limitation. It must contribute as little noise as possible. It must maintain the required DC voltage under changing conditions. And in high-current applications, it must provide adequate energy storage.

Current delivery is particularly important. It can be limited by the size, type and configuration of the power transformer, by the impedance of the power supply itself, and by the amount of stored energy available when the circuit suddenly demands it.

Noise is another critical consideration. A poorly designed supply can radiate EMI and RFI into sensitive circuitry. It can also introduce noise directly through excessive AC ripple, switching artifacts, grounding problems and other mechanisms. In a high-gain circuit such as a phono stage, seemingly small problems in the power supply can become very audible problems downstream.

Voltage regulation is about maintaining a stable DC voltage as operating conditions change. I sometimes think of this as the “stiffness” of a supply - its ability to maintain the voltage the circuit needs despite changes in load or AC line voltage. In many of our circuits, we use series voltage regulation, sometimes with local feedback, where regulation provides an advantage.

Capacitance also plays more than one role. It helps filter unwanted AC components from the DC supply, while also providing energy storage. In high-current circuits such as power amplifiers, those capacitors become reservoirs that can supply energy when the amplifier demands it.

All of this is why I spend so much time thinking about power supplies.

They aren't simply something that powers the audio circuit.

They are part of the audio circuit.

And ultimately, the music coming from an amplifier is the controlled translation of energy from the power supply into an audio signal.

Elegance. Simplicity. Truth.

ModWright Instruments Inc.

09/14/2026

A Pure Analog Moment

Last weekend I took a break and spent some time just out of town, w**e tasting and generally enjoying life.

It was peaceful, relaxing and deeply satisfying. And it made me think about the value of experiences like these in our lives.

I've talked about Pure Analog Moments before—moments when we step away from the stress, technology and constant demands of daily life. But perhaps what I've really been talking about all along is something simpler: experiences that allow us to be completely present.

I was sitting in a comfortable chair under a sunny sky, with a light breeze moving through the vineyard in front of me. Everything was lush and green. The w**e was full-bodied, rich and flavorful.

Around us, other people were doing much the same thing. Talking. Laughing. Enjoying each other's company. Nobody seemed particularly concerned about what came next.

For that little stretch of time, neither was I.

We need more of this.

More peaceful, calm and fulfilling moments when there is nothing to accomplish, nothing to solve and nowhere else we need to be.

I realized later that this is very similar to what I value about listening to music on a good system.

The equipment isn't really the experience, just as the w**e wasn't really the experience.

It creates the opportunity for something else.

A chance to let the mind unwind. To explore. To feel something. To become absorbed in the moment rather than thinking about the next one.

Maybe that is what a Pure Analog Moment really is.

Not an escape from life.

A chance to experience more of it.

Elegance.Simplicity.Truth

ModWright Instruments

09/10/2026

Noise: The Silent Killer of Good Sound

Good audio design is often an exercise in reduction, not addition.

The musical signal we are reproducing needs nothing added to it. Bass, treble and midrange don't need to be accentuated or manufactured. They are already present in the recording. Our job is to reproduce that signal as faithfully as possible.

Noise is one of the biggest deterrents to achieving this.

I'm not talking about obvious hum or buzz. Those are simply never acceptable from the loudspeaker, full stop. I'm talking about something more subtle: the noise floor.

The audio signal is delicate and nuanced. The best audio equipment does as little as possible to get in its way.

There are many sources of noise. Some, such as 1/f noise and thermal noise, are inherent in electronic devices and cannot simply be eliminated. And let's be honest, if you put your ear directly against a speaker driver, you're probably going to hear something.

The objective isn't the literal absence of noise. It is reducing noise to a level where it no longer interferes with the reproduction of music.

Ground noise, AC ripple, induced EMI and RFI are among the other challenges.

I recently wrote about the importance of physical layout and how component orientation, wire routing and geometry can prevent noise from being induced or injected into the audio signal path. But layout is only part of the equation.

Power-supply design, thermal management, grounding and ground routing, shielding, signal-path length and signal integrity all matter.

And when designing a phono stage, all of this becomes even more critical. The signal coming from a phono cartridge is extraordinarily small. Noise that might be insignificant elsewhere can become very significant at this level.

Two pieces of audio equipment could be built from exactly the same schematic and bill of materials and still perform and potentially sound very differently if the implementation is not equally well considered.

The art is in the implementation.

Grounding. Layout. Shielding. Power supply. Signal integrity. None exists independently of the others. It is all a matter of synergy.

Good audio design requires a holistic approach.

And often, that last fraction of a percent, the difference between something that works and something truly refined, comes down to experience.

Elegance. Simplicity. Truth.

Dan Wright
ModWright Instruments

09/07/2026

Weekend Listening

I've been listening to Elbow this weekend.

I like the dark and emotive tone as well as the layering of instruments and sounds.

If you haven't heard this, I would check it out.

What are you listening to this weekend?

Dan Wright
ModWright Instruments
Elegance.Simplicity.Truth

09/04/2026

Layout is Critical

Circuit design is critical, but implementation is equally important. A well-designed circuit with poor implementation can be noisy, unstable or unreliable.

Alignment matters.

When I lay out a design—whether it is a circuit board or the physical arrangement of components inside a chassis—I always think in three dimensions. Perhaps my Mechanical Engineering background makes this easier for me, but it is an important part of how I approach audio design.

The issues include heat, radiated noise and induced noise.

Heat may be the easiest to understand. We can't place heat-producing devices next to components that are sensitive to temperature, including certain capacitors, wiring and other parts. Airflow, spacing and the physical relationship between components all matter.

Noise is the bigger challenge because much of what causes it is invisible.

RF and electromagnetic interference are two significant sources. RF requires attention to shielding, grounding and decoupling. Wiring can be shielded, circuit boards can incorporate shielding and ground planes, and the physical placement of RF-carrying conductors relative to a grounded chassis can help control radiated energy.

Electromagnetic interference, or EMI, is another major consideration, particularly around power transformers and other inductive devices. The electromagnetic field is invisible, but it is not unpredictable. Its geometry and orientation can be understood and used to our advantage.

The orientation of transformers, inductors, circuit boards and wiring can therefore make the difference between inducing unwanted noise into a sensitive circuit and largely nulling its effect.

Power-supply wiring presents another challenge. In very sensitive circuits such as phono stages, even DC supply wiring carrying a small amount of residual AC can become a source of noise. This is where techniques such as twisted pairs, careful routing and crossing signal and power wiring at 90 degrees become important.

Whatever the source of the noise, a good designer has to visualize the physical space inside the component in three dimensions.

The schematic tells us how the circuit works.

The layout determines how successfully that circuit becomes a real product.

Orientation matters. Geometry matters. Implementation matters.

Alignment matters.

Elegance. Simplicity. Truth.

Dan Wright
ModWright Instruments

09/01/2026

Simplicity in Design

The straightest-line solution is not always the simplest, and the simplest solution is not always the best. Complexity for complexity’s sake, however, is almost never the right answer.

When we design audio equipment, we naturally look for the most elegant solution. Often it is the simplest—but not always.

Each new design begins with a clean sheet of paper, but it also draws upon time-proven circuits, concepts and solutions. Every design presents its own challenges and often its own unique goals. Most of the time, the solution is built around core concepts and proven circuits that become the building blocks of the overall design.

It is in the finer points—the stitching together, if you will, of these concepts into a complete design—that experience, skill and discernment matter most.

The best designs are conceived, tested and proven, and then distilled down to their most refined form.

When we achieve that, we have a design that we are proud to put the ModWright name on.

ModWright Instruments Inc.
Elegance. Simplicity. Truth.

08/30/2026

It has been a very busy couple of weeks at ModWright.

This stack of boxes is a pretty good representation of how busy we have been.

We are a small company, and everything we build is assembled, tested and finished here by myself and my people, who care about the quality of our products.

Right now we are running several weeks behind, which is a good problem to have.

I still spend a lot of my time doing the same things I have done for more than 25 years - designing, troubleshooting, testing equipment and working alongside my team.

As ModWright has grown, some things have changed. But one thing hasn't. When a piece of ModWright equipment leaves here, it must always be something that I am proud to put my name on.

Thanks to everyone who has chosen ModWright recently. We don't take it for granted.

These are headed out the door.

Time to build some more.

Dan Wright
ModWright Instruments
Elegance.Simplicity.Truth

08/28/2026

Tonight's Pure Analog Moment.

It's been a busy couple of weeks at ModWright. That's great, but at the end of a long day I really need time to find my center again.

Tonight that means Antonio Carlos Jobim - Stone Flower

No critical listening. No engeering. No emails. Just music.

This is why I design audio equipment in the first place.

What's playing in your system tonight?

08/26/2026

Why I Still Use Transformers in Audio Designs

I have used transformers and other inductive devices in audio circuits for many years. They are more expensive, take up more space, and require careful implementation.

So why do I continue to use them?

Because they allow me to do things in an audio circuit that are difficult to accomplish as elegantly in other ways.

Transformers and inductors use magnetics and inductance rather than simple resistance. In a tube circuit, for example, an inductive plate load can present a very high AC impedance to the music signal while having relatively low DC resistance.

That distinction is important.

A resistor presents essentially the same resistance to both the audio signal and DC. Increasing its resistance can improve the AC load seen by the tube, but it also creates a greater DC voltage drop and dissipates more energy as heat.

An inductive load behaves differently. It can present a very high impedance to the changing audio signal while maintaining relatively low DC resistance. This allows me to give the tube the load it wants to see without requiring unnecessarily high supply voltages.

There are active ways of accomplishing something similar. Tubes, transistors and MOSFETs can be configured as constant-current loads. They work very well, but they also add active devices and complexity to the signal circuit.

My preference, when the design allows it, is often the passive approach.

Transformers can do much more than simply act as loads. I use them for impedance matching, phase splitting and combining, signal coupling and converting a high-impedance tube output into a much lower output impedance.

One magnetic component can sometimes perform several functions very elegantly.

There is no single "best" way to design an audio circuit. Every approach involves choices and compromises.

But over the years, transformers and inductive devices have become an important part of how I design.

They allow me to achieve the electrical characteristics I want while keeping the circuit relatively simple.

And ultimately, that is what matters to me.

Elegance. Simplicity. Truth.

Dan Wright
ModWright Instruments

08/22/2026

Communication is Key:

I was texting a customer from the park as I walked my dogs this morning, and it struck me how technology has enabled communication.

At ModWright, our customers are most important to us and communication is key.

We will always answer our phone and will always take your call or email. In a world of AI, we will remain constant in this.

We value customer feedback.

Life isn't perfect and sometimes things happen. That is where service counts most.

We service our products for life.

It more than a mission statement. It's how we do business.

Elegance.Simplicity.Truth

ModWright Instruments

ModWright Instruments

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