Dynacomp volume swells

[moritz]

I have one of those Dunlop reissue MXR dynacomps and I'm finding that when I hit a note, the volume sometimes seems to increase ever so slightly over time, creating a very subtle swell type effect. This swelling is not overly pronounced (quite subtle in fact) and seems to come and go depending on my picking dynamics. Being a compressor, this is obviously a by-product of the compression taking place, however, I'm wondering if there's any way to tone it down a bit? Would that little trimmer inside affect this in any way? It's not really all that bad, but if there's a simple way to tame it, then it's something I'd like to do...

Any help much appreciated.

[Mark Hammer]

If I'm not mistaken, the extent to which the gain of the 3080 chip is affected is determined by the combined resistance of the 27k fixed resistor and the 500k compression pot it is in series with (http://www.tonepad.com/getFile.asp?id=9).  So, in theory, if you add a bit more resistance to that combination, the envelope signal will affect the gain of the 3080 less: essentially a bit like being able to turn the compression amount down even more.

Well, if that's the case, why not just turn down, right?  That is a possibility but I suspect the concern is that you want to be able to know you've set it for max compressin without having to futz around and find the spot where compression is max without problems.

So, try replacing that 27k resistor with maybe a 47k or 68k unit.

[moritz]

Thank you Mr. Hammer!... Another one of your wise and well-explained answers; makes perfect sense!
I'll have a play around with that resistor and see what I can come up with.
Thanks again!

[markm]

Of course, I beleive there are some recovery mods for the Dyna/Ross circuit as well.

[Mark Hammer]

Those mods are always worth pursuing, but there doesn't seem to be any problem with the recovery, based on the description provided.  Rather, the issue seems to be one of so much gain reduction that a recovery rate which ought to be natural sounding sounds like the has been knocked down and is struggling to get up.  I guess one needs to think of it in terms of the contrast produced and the amount of recovery that needs to occur within the time allotted.  Modest gain reduction, recovering over the same time period sounds fine.  A huge change in gain reduction, recovering within the same time frame (before the note has actually decayed) sounds like volume being turned up rather than constant volume being maintained.

I don't mean to sound glib about it, but this is a kind of basic perceptual principle that keeps coming up in a number of different contexts.  The punchline is that the rate something seems to happen at is a function not only of how much time is occurs in, but also how much there is to be accomplished, or how much change takes place.  In the case of autowahs, a great many of them sweep just as fast as the Mutron, but because the Mutron will sometimes be set to sweep fairly wide, it sounds like it is going even faster because it covers more ground in the same time interval.