Change fixed gate attack time

[sodderboy]

I am trying to make a gate usable by decreasing it's attack time.  Currently attack is about 600 mS.  Is the attack created by the time constant C10/R21?  I figure that I would want to decrease the value of C10 to decrease attack time.  Is this correct?

Hmm the link did not work

http://www.twin-x.com/groupdiy/albums/userpics/Gate_CV.pdf[
Mike

 

[L´Andratté]

What circuit are you referring to?

Edit: Now it works!

 

[JohnRoberts]

In that circuit it looks like the attack time is defined by Q3 discharging C11... 600mSec seems awfully long for that.  Perhaps dropping the impedance of R19,R21,and C10 will drive Q3 harder and discharge C11 faster (or make C11 smaller, but then the release time constants are off... Q2 is also discharging C11.

I am making guesses about the rest of that circuit so I may be misreading something. Is D7 a LED for a LDR?

JR

 

[PRR]

> decreasing it's attack time.

Attack or release?? Ambiguous in a gate.

This circuit reacts fast, few milliSeconds, when sound starts. When sound stops, P6 C11 is indeed like 500mS, and adjustable.

If it is cutting-off the first transient, I would (as I see JR said) reduce impedances in the R19 C10 R21 network.

Or just use a smaller C10 C11.

 

[sodderboy]

. . tac is too slow on the gate. . . lease is adjustable so no problem there.
. . .ry changing C10 and adjust release.
. . .s guys! 

 

[JohnRoberts]

Not to put words in his mouth but I suspect he meant C11.

Note: for some gates, too fast of an open time can cause clicks, but so does too slow of an open with LF source.

JR

 

[abbey road d enfer]

I am trying to make a gate usable by decreasing it's attack time.  Currently attack is about 600 mS.  Is the attack created by the time constant C10/R21?  I figure that I would want to decrease the value of C10 to decrease attack time.  Is this correct?

Hmm the link did not work

http://www.twin-x.com/groupdiy/albums/userpics/Gate_CV.pdf[
Mike

In addition to all that's been said, remeber that the attack time is extremely dependant on the level, because the discharge current is governed by the current injected in the bases of Q3. I would think that reducing R19 & R21, whilst increasing C10 may provide a better current drive to Q3. Not sure if that would audibly improve the situation, though.
I believe the biggest design flaw is having single-wave detection only (only negative signals at R16 are accounted for).

I have some history with that design; in the mid-seventies, a company approached me, they had made a batch of gates based on a design they had ripped off from an MXR pedal. Users complained about erratic triggering. I modified their units with a phase-inverter and an additional transistor and they had much less complaints.