I have experienced noise coming from my Keeley Comp pedal and SD tremolo but when I connected them to the loop in my Foxrox Zim pedal the noise is almost gone. The Zim is true bypass and the noise reduction effect is there whether it´s on or off.
Has anyone else had this experience with reduced noise when moving true bypass pedals around?
Can I get the same effect from a buffer?
What's your power supply situation? Any unusual signal routing?

This sounds like a ground loop. A buffer won't solve it. It doesn't really have anything to do with the fact that they're true bypass.
Thanks for a quick reply.
I use Ciocks Big John as a power supply. The routing is just a few pedals with patch cables.I changed the pedals around looking for when the increased noise appeared and my conclusion was that the Seymour Duncan Shapeshifter tremolo added noise where ever I put it. The compressor was silent even at extreme settings when the SD trem was just sitting on the floor. The strange thing is that when I connect the tremolo straight into the amp, no other pedals in the signal chain, it is noise is low a little bit louder then when it´s not engaged, but low.

After doing some back and forth my verdict is that the matter is mostly psychological. The fluttering of the (very) low noise makes it a lot more obvious that there is something, and I´m not saying annoying, just tele background noise (I´m not familiar with a better word to describe it but a low sounding static).

I guess I´ll be looking for a new tremolo pedal that also conserves some pedal board space. The SD is not bad, just not perfect.