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Reviewer: Marja & Henk
Financial Interests: click here
Sources: PS Audio PWT; PS Audio PWD; Dr. Feickert Blackbird/DFA 1o5/Zu DL-103; Phasure NOS1 DAC [in for review]
Streaming sources: XXHighEnd; iTunes; Devialet AIR
Preamp/integrated/power: Tri TRV EQ3SE phonostage; Audio Note Meishu with WE 300B (or AVVT, JJ, KR Audio 300B output tubes); Yarland FV 34 CIIISA; Qables iQube V1; Devialet D-Premier; Hypex Ncore 1200 based monoblocks; KR Kronzilla SX Eco [in for review]
Speakers: Avantgarde Acoustic Duo Omega; Arcadian Audio Pnoe; Vaessen Aquarius; Crystal Cable Arabesque Mini [in for review]
Cables: complete loom of ASI LiveLine cables; full loom of Crystal Cable cables; Nanotec Golden Strada #79 nano 3; Nanotec Golden Strada #79; Nanotec Golden Strada #201
Power line conditioning: Omtec Power Controllers; PS Audio Powerplant Premier; PS Audio Humbuster III; IsoTek Syncro; Blue Horizon distortion meter [in for review]
Equipment racks: ASI amplifier and TT shelf
Sundry accessories: Furutech DeMag; ClearAudio Double Matrix; Nanotec Nespa #1; Exact Audio Copy software; iPod; wood, brass, ceramic and aluminum cones and pyramids; Shakti Stones; Manley Skipjack; Blue Horizon footers [in for review]
Room treatment: Acoustic System International resonators, sugar cubes, diffusers
Room size: ca 7 x 5m with a ceiling height of 3.50m, brick walls and concrete floor downstairs,
ca. 14.50 x 7.50m with a ceiling height of 3.50m, brick walls, wooden flooring upstairs.
Price of review item: €950

A pre filter for the AC aka the IsoTek Evo3 Syncro. We all know it. The mains supply we connect our precious audio gear to is far from prefect. It is full of noise by way of RFI and EMI. Our review of the Blue Horizon Noise Analyser depicted the reality of this grim outlook in unexpected detail. One thing that noise analyzer however did not show was another unwanted component that rides the mains lines like an evil freeloader. This is a DC offset component.

Somewhere literally down the line there is an asymmetrical load. This load on the mains can last for a varying amount of time, often from between a second to a few minutes. Then it vanishes again only to return later. From ‘our’ end its behavior is utterly random. One of the reasons that late-night listening can be so favorable is that this transient DC pollution is less than during the day. What exactly such DC pollution will cause to our hifi varies with installations.


In many cases DC signal will cause transformers to vibrate which can be heard directly as a mechanical buzz. It gets worse when that mechanical vibration triggers microphonic tubes in the circuit. This can happen not only to the piece of equipment with the resonant transformer. Vibrations can also travel through the audio rack to another device and cause havoc there. It’s one of the reasons all manner of footers and isolating devices have an effect. It all goes back to this exchange of physical resonances between components. Smaller toroidal transformers are less prone to the detrimental effects of DC offset, however larger transformers of this type are very sensitive and might suffer momentary saturation.

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