MXR envelope follower..?how works?

[Paul Perry]

Thanks everyone.... consensus is that it's a switched capacitor
filter, pulse width modulated by the envelope.
Certainly, this is what I suspected..... but the ckt is by no
means obvious to me, even knowing this. I'm putting it in the
'weird' basket (with a few Electroharmonix things and the Korg MS20 VCA)
until I become wiser or marry a qualified Electronic Engineer
(both unlikely at this stage).

This sort of thing does make me wonder how many 'cheap tricks' are
lurking out there in pedals....

paul perry melb aust