icOn Passive Preamplifier — Frequently Asked Questions

The icOn has multiple outputs that can be activated individually or in combination via remote control. This is useful if you run multiple amplifiers or a headphone amp without always having them paralleled.

Yes — the icOn 5 Zen includes a smart mono function offering L+R sum, left channel only, and right channel only.

The icOn uses a high-quality optical encoder — the same type found in high-end professional and studio gear. It doesn’t have the fast-spin feel of mass-market consumer devices. This gives you precise, repeatable control rather than coarse jumps.

The tilt control operates exactly as its name implies: it produces a very gradual change in balance across the musical spectrum without changing the overall subjective level. When set to −1, there is a gradual fall of only 1 dB from bass to treble, with the maximum rate of change at the centre (900 Hz) of no more than ¼ dB per octave.

This absence of any sudden change means no “colouration” is added to the sound. The sound remains entirely natural but with a slight added warmth. It is available as an option on icOn 5 Single-ended models in 8 steps of 0.5 dB, from −2 dB to +2 dB.

Yes. AV bypass allows a home theatre processor to take control of your amplifier directly, bypassing the icOn’s volume control. This means you can use the icOn as your stereo preamp without disrupting your home theatre setup.

The autoformers themselves do not change with use — the copper wire and magnetic cores simply don’t change in the short term. However, many icOn customers report noticing an improvement after around 100 hours of listening.

Pal’s honest view: this improvement happens in the listener’s brain, not inside the preamp. Autoformers produce a sound that is quite different from resistive passive attenuators or active preamps. Your brain “learns” this new sonic experience and adapts to the complete absence of background noise and distortion — the higher transparency. Some audiophiles call this adaptation “burn-in.”

“I’m an engineer and a music lover, but I prefer to stick to scientific and engineering facts. Maybe I’m wrong about the science — who knows? As always, YMMV… 😊” — Pal

No. The external wall wart is not directly connected to the signal path — the signal path is fully passive — and it is galvanically isolated from the internal power supply circuits. The display lighting and the microprocessor cannot detect any difference between an SMPS and a linear power supply.

The prejudice against SMPS in the audiophile community largely comes from generalisation. Yes, 20–30 years ago it was often true that linear power supplies performed better. Today, this is simply no longer the case. Modern high-frequency switching devices often outperform traditional 50–60 Hz linear supplies.

A few facts the power supply “experts” usually overlook:

• When the switching frequency is 100–1000× higher, it becomes much easier to filter and suppress noise (50 kHz–1 MHz instead of 50 or 60 Hz).
• Noise from an SMPS is proportional to the current drawn — there is a huge difference between an SMPS in a power amplifier and the very low-current SMPS used in the icOn.
• Modern digital audio devices are filled with tiny SMPS modules embedded on the PCB. Audiophiles don’t see them, don’t know they’re there, and never complain about them.

Pal’s completely honest opinion: the SMPS used in the icOn is not inferior to a pure linear power supply.

From 2016 to 2019, Pal used TVC transformers from SAC Thailand. They were good, but not the best. Today, the finest magnetic attenuators are the autoformers made by Dave Slagle. They deliver a significantly better, more transparent sound with no coloration.

Pal uses only custom copper autoformers that Dave Slagle builds specifically to his specifications. The silver autoformers are produced in-house by Paul Grand Audio.