Noise Supression on EHX Holy Grail Reverb?

[S. Thompson]

I don't really know how to phrase this, so I'll just relay my situation.

Basically, I have a Big Muff NYC reissue on my board before an EHX Holy Grail reverb (the original housing - purchased in 2007).

The big muff is super noisy with any of my guitars which I have heard many people complain about in the past, but when I switch the reverb on, there's no noise when I'm not playing.

So my question is - does the reverb have some kind of noise suppression functionality? Is this just some kind of crazy thing going on in my chain?

Either way... kind of good to know I can avoid the noise by using both simultaneously.

- Steve