- Joined
- Apr 28, 2007
- Posts
- 5,494
- Likes
- 1,084
Hi Mike:
I think the reason John adviced against use of DC-offset blocking networks was concern for safety—as failure of such can result in a fire. Given that these are used on the primary side, I don’t think he was advising against them for performance reasons.
Of course on the secondary side it is important to use outlets/power strips that have zero filter elements at all. The whole concept being to reduce the impedance between the grounds of all attached equipment (reducing the interaction of the inevitable leakage loops which form between all components with AC-connected power supplies). And the point of the isolation transformer is simply that it is a VERY effective surge suppressor and line noise filter.
BTW, here in the USA DC offset in our AC lines is rather rare. Occurs much more in Europe. Even there, blocking of the offset is not a sure-fire cure for transformer lamination hum. Such is a bit inevitable with big trannys—and it is often worse in 50Hz countries.
Hey Alex! Thanks very much for the clarification!
I couldn't remember the details of John's advice regarding DC filters (nor even how to spell his first name!) LOL
Like watching a movie you haven't seen in years, everything you've written came back to me as I read it. Sheesh!
And for those who don't know Superdad, he and John Swenson are the guys behind UpTone Audio, who produce all the products seen here, which I have no reluctance to plug, as I'm a huge fan of their products and their knowledge of all things related to noise reduction:
https://uptoneaudio.com/
https://www.computeraudiophile.com/forums/forum/25-uptone-audio-sponsored/
In other words, whenever you see a post by Superdad or John Swenson, here or at ComputerAudiophile, pay attention!
Mike