Hi Thomas,
He makes a number of very good points in his videos about the limitations of isolation transformers. If it is fed with a “distorted” waveform on the primary coil (i.e. not a perfect 50/60Hz sine wave), then it will reproduce a similarly “distorted” waveform out from the secondary coil.
Hence it is helpful to be clear about why you may or may not want an isolation transformer. It is not a cure-all for every form of dirty mains.
We wanted to block so called dc offset or asymmetric mains, as this is a major cause of saturation and mechanical hum in Naim’s toroidal power supply transformers. The isolation transformer or balanced power supply has done this for us.
If you want to block higher frequency harmonic distortion on the mains waveform, then a BPS such as ours is not very effective. Airlink offers an optional module which you can specify as an add on to the basic BPS which claims to do this. However, we didn’t want to go there. We just wanted to block the dc offset with a very low impedance (hence large) BPS.
A full-on mains regenerator should remove both dc offset and any waveform distortion so sounds ideal. The catch is that it has to be a very big beastie in order to have a very low impedance - the low impedance that a Naim power supply expects to function well. And that means large, heavy and expensive.
Hence the choice: find your own dc blocker that works without degrading the Naim power supply performance, pay about £500-800 for a BPS which knocks out dc offset but not the waveform distortion, or pay about £10,000 for a beastie of a mains regenerator.
There may be a secondary benefit of a BPS, though would welcome comment from those who understand such matters better than I. With the output from a BPS, the “neutral” wire in a hifi component’s mains cable is no longer at zero volts but is at the opposite voltage to the live wire. Does the electromagnetic field from the neutral therefore cancel out the EM field from the live, resulting in almost zero EM fields from all the mains leads. If so, this would result in less sensitivity to cable placement and the need to avoid keeping interconnects and speaker cables away from mains cables. I would be really interested to learn if this is true or false.
A couple of forum members have their own dc blocking circuit. I am not competent to go there so have gone with a BPS after having an unsuccessful trial with a very well regarded, £3k mains conditioner. You may choose try a mains regenerator.
Whichever option works for you, go for it and enjoy your music even more.
Best regards, BF