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[First post] 33609 geek question


Established Member
Hello all :) Nice forum here, been lurking for a while and decided to sign up (hello Paul W).

I've wanted a 33609 since using a hardware one in a studio a number of times over the last couple of years. I repeatedly told the studio owner I was going to steal it, but thankfully now I don't have to :D

Anyway, so I have a question that I have to ask as a geek. I know, I know, 'just don't worry about it and make music' etc etc, but I am interested in this stuff, so hopefully there could be some answers forthcoming here :)

From the UAD site's article on modelling the 33609;

The other unique feature of the 33609 is the Auto Release function. In most cases, auto release is accomplished by making the release circuit a second-order filter, leading to a variable release time depending upon input signal statistics. The second-order release is used by compressors such as the 1176 and the Fairchild 670 (in modes five and six). For the 33609, auto release is also accomplished by a second-order filter, but a nonlinearity placed within the filter changes the behavior of the circuit. Because of this nonlinearity, the 33609 Auto Release behaves differently from other compressors.
'Behaves differently' - how? What effect/s does this nonlinearity have exactly? Is there a more detailed article anywhere?

I know these are pretty 'pointless' questions, but I find that understanding what something is doing helps me use it better, and in the right situations more often.

Cheers all! :)




Established Member
Of course, the archive :oops: :oops: :oops:

I wrongly assumed that - because of the timing, pretty close to the plugin release - that there wouldn't be any other articles about it on a UA site.

Apologies, and thanks. :)

EDIT - none of those answers my q :( , but thanks anyway :)


Venerated Member
Here's the explanation (part of the text you pasted):

\"For the 33609, auto release is also accomplished by a second-order filter, but a nonlinearity placed within the filter changes the behavior of the circuit.\"

To know exactly what the \"nonlinearity\" is that is placed within the filter, you probably need to call and ask the engineers at Neve (and also the engineers at UA since they modeled it). I don't think there are more detailed articles about it than there is already on the Webzine (which seem to be plenty for folks like me), but my guess would be that very specific design questions such as yours could best be answered by the engineers that designed this compressor (that is, if they are willing to go into such details).


Established Member
Hello, thanks for your reply.

I knew the filter was there, it's just the effect it has being placed where it is that interests me. My ears couldn't care less :D :)

Cheers :)
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