[sdiy] Equiv of LM3900?

[mark verbos]

You can't really replace a 3900 with a regular opamp. It is a morton 
amplifier, that is something different. They shouldn't be THAT hard to find.

you could try the Buchla 230. It has adjustable decay and ac/dc 
coupling. This ac/dc control is suposed to change the "feel" of the 
response. ac only triggering on real peaks in a dense mix.  You could 
probably add an attack control just like in a attack/release envelope by 
puttin the diode the other way and adding a control.

mark

Synth-DIY wrote:

>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
>
>