Transformer hum caused by Devialets?

[hardcore]

I use Plixir balanced isolation transformers for the power conditioning of my Devialet 1000 Pro. The isolation transformers don't hum. I've not tried the isolation transformers with a 220 or 440 Pro.

However, I have an LG OLED TV, which *will* cause the isolation transfomer to hum if I connect the TV to the output of the isolation transformer. So my TV is connected via a regular power conditioner.

Transformer humming is usually caused by a DC offset it the AC supply.

You might want to try the ifi DC Blocker to see if it helps your case - although it doesn't fit directly into the IEC power port of my Devialet 1000 units.

https://ifi-audio.com/products/dc-blocker/

Good reply. I’ve had exactly the same in the past. A DC Blocker sorted it. A transformer will not pass on DC but it will hum. DC offset can be readily measured on the mains with a basic multimeter.

Thank you also for this tip. We also initially suspected that DC could be the cause. That's why, as I wrote above, we put a DC blocker between the transformer and the Devialet. This had no effect whatsoever. The transformer also has its own internal DC blocker. At least for the moment, I would therefore rule out DC as the cause.
But interesting that you had the same phenomenon, if I understand you correctly. Switching on the Devialets led to a transformer hum?

DC blockers only work to a certain value of DC offset. As Pim mentioned, the switching power supply of the Devialet probably creates strong distortion on the power supply 'kicking back' spikes to the isolation transformer.

My 250/1000 Pros don't have that problem with my isolation transformers though. I've used 2x250 Pro off one isolation transformer but am now using separate isolation transformers for each amplifier.

Have you tried changing the Devialet power saving settings? Many of us have disabled the power saving setting since it sounds better. I wonder if that would have any effect?