[sdiy] Equiv of LM3900?

[Synth-DIY]

Hi!

What would be a good replacement of a LM3900, which seems less than easy to get
were I am?
Any quadrule opamp like a TL074?

I mean to use it in a slightly modified version of  "Nicholas Collins envelope
follower" from EN. (I only have a gif of the schematic so I don't know what EN
issue that would be.)

...I of course open to suggestiosn of a env.follower with adjustable Attack/Decay
and gate out.


thanks!

//Per Mattsson