In-wall power improvements for high end audio systems. It's big!

Official - Technical Discussions
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I ran into Vince at AXPONA and mentioned I upgraded my electrical system prompted by an email from him last fall with a copy of his white paper contained in this thread. I followed the instructions precisely as recommended. Vince asked that I share my results. So, here are my notes.

I recently completed (March 2025) the installation of six dedicated branch circuits off a new Eaton CH panel (CHP22B100X2), fed by 4/3 NM-B (solid #8 ground) from the main service panel. The goal was to provide stable, high-quality power to my audio system.

Directional Orientation Experiment

Under the hypothesis that power directional flow (line to load) may have a sonic impact, I oriented four circuits South (subpanel) to North (receptacle), using one end of the cable reel as the North reference and the cut-off end as South. The remaining two circuits were installed North to South.

While the drywall was open and the Romex cables remained un stapled, I reversed orientation to see if I could detect an audible difference. And I did, not significant but certainly audible and much fuller and more body to the audio one direction over another. Over the next few weeks (or until my wife gets tired of looking at bare framing studs), I experimented by swapping equipment connections between outlets. So far, I prefer south to north and the Hubbel receptacles over the FURUTECH. I just have no choice but to use Furutech on the 8/2 cables.

Installation Details

Circuits & Wiring

  • Two circuits: 8/2 NM-B, each feeding a Furutech GTX-D NCF(R) duplex receptacle
    • One North to South, the other South to North
  • Four circuits: 10/2 NM-B, with 3 Hubbell 5362 Industrial Grade and 1 Furutech GTX-D NCF(R) duplex receptacles)
    • Three South to North, one North to South
  • All six circuits run on 20A Eaton CH breakers.

Grounding & Surge Protection

  • Installed two additional ground rods, lowering earth resistance from 5Ω to <1Ω(measured with an ETCR2000XC Ground Resistance Tester).
  • Installed SPDs (Surge Protective Devices) in both the main service panel and the sub panel (per NEC recommendations).
  • All branch circuits are under 15 feet from receptacle to sub panel.

Performance Measurements & Objective Data

Conductivity Improvements (IDEAL Suretest Analyzer)

  • Hot/neutral resistance dropped from 0.5Ω to <0.008Ω.
  • Voltage drop under a 15A load improved from 10% to ~1%.
  • Available Short Circuit Current (ASCC) increased from 156A to >1000A (1300A on the 8/2 circuits).

EMI/RF Noise Levels (Trifield EMI Meter)

  • No significant change in measurable noise (~50mV before and after).
  • Twisted the Romex wiring as a precautionary step for common-mode noise rejection.

Audio System & Power Setup

Power Amplifiers

  • PS Audio BHK 600 mono blocks → directly connected to Furutech GTX-D NCF(R) outlets on dedicated 8/2 NM-B 20A circuits. HRS DPX 14.5” Damping Plate on each amp. The amps are on HRS SXR stands.
  • Interconnects/speaker cables: Transparent XL & Reference.
  • Power cables: AudioQuest Dragon High Current and Source cables.

Source Components & Power Conditioning

  • MSB Reference DAC with HRS DPX 14.5” Damping Plate & Rose 150B streamer → connected to a Puritan 156 power conditioner on a dedicated 10/2 20A circuit with a Furutech GTX-D NCF(R) duplex receptacle. Rose 150b is only used to display music playing from Roon. The music is streaming from the Mac Pro server in another room direct to the MSB Renderer module via an LHY 6SW switch and Muon Pro Ethernet filter.
  • The Puritan drops EMI noise from 50mV+ to <10mV and subjectively improves sound quality.

Turntable & Phono Stage

  • Dr. Feikert TT & CH Precision P1 phono stage w/o X1 separate power box (added 3/25 replacing PrimaLuna EVO 100 phono stage) with HRS DPX 14.5” Damping Plate → directly connected to a dedicated 10/2 20A circuit (no power conditioning). This phono stage was the reference for Michael Fremer until he upgraded to the CH Precision P10. The P1 is an amazing upgrade from the Prima Luna EVO 100 which was wonderful in its own right and price point.

Subwoofer & Speakers

  • REL 212/SX subwoofer → directly connected to a dedicated 10/2 20A circuit with a Hubbell 5362 outlet.
  • Wilson Sasha Vs

Receptacle Upgrades

  • 3 Furutech GTX NCF & 3 Hubbell 5362 Industrial Grade receptacles.

Listening Impressions & Initial Thoughts

This upgrade has produced a quite noticeable improvement in sound quality. Even my wife (a great reference point) immediately heard a difference.

Key Observations:

:white_check_mark: Greater micro-detail retrieval, tighter image localization and shocking 3d sound stage compared to original setup.
:white_check_mark: Lower noise floor, allowing for higher listening levels without fatigue
:white_check_mark: The MSB Reference (as a preamp) can now be played above 75 volume, whereas before, above 70 could be harsh

The results have been very rewarding and a worthwhile upgrade, despite the drywall mess!

Thanks to Vince for sharing the white paper and details on how to install the dedicated power lines.

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22

John,

Thanks for sharing the detailed process. Funny you mention your wife’s impression as a metric. Jonathan’s wife often hears differences from an adjacent room that we struggle to define. A great reference point indeed.

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Just offering my 2 cents. When Vince describes avoiding “false economy” when implementing his approach, he genuinely means it. FWIW, I can hear a material difference in the solidarity and attack from my furutech duplexes fed by 6A AWG branch circuits vs those fed by cyro’d 10 AWG branch circuits. In this regard, my amp is fed by the former while my sources by the latter (because I’ve found the 10 AWG circuits to be more resolving when feeding my sources). All to say, I would encourage those who are spending significant $s to implement a power infrastructure upgrade to maximize the gauge wire feeding their sub panel (for me that was a twisted 125A 1/0 1/0 1/0 + 8AWG untwisted ground) and then run twisted lower and higher gauge wires from their sub panel to their listening room duplexes recognizing that amps and sources may respond differently to gauge.

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