Why invest in your power supply?
“Ultimately, every sound we hear is the direct result of modulating the electrical energy provided by the mains. It is this energy, precisely transformed and controlled, that powers every stage of the audio system all the way to the speakers.”
According to Nic Poulson — founder of ISOL‑8 and Trilogy Audio Systems and a key figure in professional audio design — electrical power is the cornerstone of sound quality. Every component in your hi‑fi system, from DACs to amplifiers, depends entirely on the quality of the electricity it receives.
That’s why ISOL‑8 recommends allocating at least 10% of the total system value to optimizing, filtering, and protecting the power supply. In terms of listening impact, this investment often surpasses much more expensive upgrades (such as cables or electronics), because it addresses the root cause of sound: the power itself.
Less noise = More music
Types of noise
There are many forms of noise that an Hi‑Fi or A/V system can be subject to, or that it may generate itself.
If system components emit hum, it’s usually caused by one or more of the following:
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Poor transformer design or construction
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Use of equipment not designed for the local mains frequency
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Substandard mechanical assembly
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Excessive mains voltage (surge)
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Significantly distorted mains waveform
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Presence of direct current (DC) on the power line
If noise is coming from the speakers, potential causes include:
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High noise performance from one or more devices
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Mismatched sensitivities between components (e.g., power amp too sensitive for a preamp, or speakers too efficient for a particular amp)
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Insufficient supply voltage (which may push internal regulators out of their stable range)
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Ground loops
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Absence of grounding
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Poor-quality or high-impedance grounding
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Severe mains waveform distortion
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Significant radio-frequency (RF) interference on the mains or in the environment
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Strong electromagnetic fields that affect equipment or wiring
All ISOL‑8 power filters work to reduce broadband noise conducted through the mains. Both the cutoff frequency and attenuation level depend on the model: as you move up the range, performance improves. Moreover, Axis‑equipped models block DC contamination from reaching your devices. Only a fully regenerated power source can restore a truly pure waveform, free from any anomalies.
Remember: many of the audible improvements from mains filtering come from what you don’t hear. No device is perfect, and even a small amount of unwanted energy — beyond the 50/60 Hz fundamental — can significantly impair how the device handles the audio (or video) signal passing through it. This is particularly true for high-gain gear, where the initial signal may be only a few millivolts.
Why condition your power supply?
The goal of any high-fidelity system is to make you relive the original performance as closely as possible. Our mission is to reduce compromises and bring you closer to the emotion of the music.
Each component in our system is an imperfect link in a chain. Each one transforms energy from one form to another, passing it along until it reaches you.
The most fundamental — and often overlooked — link in this chain is the mains supply, the source of power for your system. Many of us simply plug in and take it for granted. But mains voltage is the starting point of the entire chain — the very foundation upon which music is built — and deserves greater attention.
The problem
A closer look at the mains supply reveals it’s not as clean as one might assume. Examining an AC cycle in detail shows far more “activity” than expected — energy is not used in a clean, benign way. Pollution and distortion of the mains supply are inevitable and ubiquitous.
Countless devices in homes and industries draw power unevenly, converting part of it into noise — whether in the form of RF interference or waveform distortion. We all share this pollution because we share the same grid, which was not engineered with noise immunity in mind.
Many A/V devices are surprisingly vulnerable to this pollution: interference travels through them to sensitive downstream circuits, degrading system performance.
Typical manifestations include:
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RF noise causing distortion in transistor junctions
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Arc-generated spikes causing audible clicks
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Wideband noise from rectifier diodes creating a masking haze
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Industrial inductive loads distorting mains waveform
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Systems sounding better at night due to lower local electrical activity
This problem is escalating with the proliferation of Wi‑Fi, Bluetooth, and switching-mode power supplies, which add more electrical pollution.
And internal noise from each component further contaminates the system. That’s why ISOL‑8 recommends dedicated filters for each device, to prevent cross-contamination.
The solution
Removing noise from the mains can dramatically improve your system. A well-engineered filter or regenerator that isolates every component produces consistently superior performance. These benefits are real and often profound. Other fixes — like exotic mains cables — deliver unpredictable results. Addressing the root issue is far more effective than mitigating side effects.
Optimizing the mains supply is probably the best cost-benefit upgrade available. It typically results in:
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Greater clarity
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Improved contrast
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Tightened rhythm and timing
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Enhanced resolution, consistency, and emotional engagement
Contact us or visit a dealer to explore how much you can improve by examining your power supply.
Cross-contamination: explained
The issue of noise “jumping” between components is often overlooked — but reducing it can significantly elevate system performance.
The key point: every component generates noise back onto the mains, and when plugged into the same circuit, they share and amplify this pollution.
Solutions compared:
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Single filter: blocks external noise but won’t stop internal noise from spreading among devices.
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Multiple dedicated filters: ISOL‑8’s recommended approach—isolating each device so it doesn’t contaminate others—fully unleashes system performance.
Direct current (DC) on the mains
Ideally, mains power is a pure AC sine wave. In reality, many devices (dimmers, SMPS units, etc.) inject DC, distorting the wave.
Audio transformers are sensitive to DC: it saturates magnetic cores, causing hum and reduced performance even at low DC levels.
ISOL‑8 addresses this with the Axis circuit, which:
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Rebalances the waveform to remove DC offset
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Maintains current capacity
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Suppresses hum and restores system performance
The result is a perfect, symmetrical sine wave without DC offset.
Transmodal Technology
To filter noise effectively, it’s essential to distinguish between:
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Differential‑mode noise — noise between live and neutral. Requires series inductors and shunt capacitors — a more complex and costly topology.
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Common‑mode noise — noise simultaneously on phase and neutral. Can be managed with common-mode chokes and phase cancellation.
Many budget conditioners use simple “delta” filters (only shunt devices), which dump noise to ground, worsening ground quality.
ISOL‑8’s Transmodal filters:
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Combat both differential and common-mode noise
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Keep the ground line clean
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Deliver maximum filtering performance
“Optimizing mains power and eliminating transmitted noise is probably the upgrade with the best cost/benefit ratio you can make…”
— Nic Poulson, ISOL‑8
Italiano
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