Anyone have a simple noise gate build?

[tddy934]

I want to build a simple noise gate but can't find a schematic anywhere, the only ones I can find are super complicated.
I'd appreciate schematics, layouts, guides, ect.

[ragtime8922]

I have 8 right off hand and tons more in my archives. It's been years since i posted an image and don't know how. to be honest it's 2:00am and i don't feel like using the "search" option to learn how to post images right now. if someone wants to give me a quick tip on how to post schems great. if not i'll e-mail them to you. I have:

DOD FX30  Noise Gate (looks easy)
Boss Slow Gear SG-1
Korg Noise Gate
MXR Noise Gate (v2)
Distortion Box  (distortion + noise gate)
Gallien Krueger Noise Master 2000CPL
MXR Noise Gate (v1)
Noise Gate NF-1

Also, you may want to read some of Tom Scholz's patents. Some killer info.

[humptydumpty]

go to imageshack.org, upload the picture(assuming its a picture), when it gives you a direct link, copy that link, and come back to this thread

click reply, and click the little icon in the second row down, second from left and paste the url into there

[sean k]

Tonepad has the MXR noise gate with all the stuff you need to make inc build reports.

[philbinator1]

I have 8 right off hand and tons more in my archives. It's been years since i posted an image and don't know how. to be honest it's 2:00am and i don't feel like using the "search" option to learn how to post images right now. if someone wants to give me a quick tip on how to post schems great. if not i'll e-mail them to you. I have:

DOD FX30  Noise Gate (looks easy)
Boss Slow Gear SG-1
Korg Noise Gate
MXR Noise Gate (v2)
Distortion Box  (distortion + noise gate)
Gallien Krueger Noise Master 2000CPL
MXR Noise Gate (v1)
Noise Gate NF-1

Also, you may want to read some of Tom Scholz's patents. Some killer info.

whats the diff between MXR v1 and v2? 

oh yeah for images, click the "insert image" button above the smilies (2nd from left), the open a new tab and get the IMG address from
photobucket or wherever you keep your images (i couldn't figure out how to upload from my pc), then go back to your message and stick that address
in between these  >>         (they will come up after you click 'insert image'.  hope that helps!   

[ragtime8922]

go to imageshack.org, upload the picture(assuming its a picture), when it gives you a direct link, copy that link, and come back to this thread

click reply, and click the little icon in the second row down, second from left and paste the url into there

Thank you

[Mark Hammer]

here is one: http://hammer.ampage.org/files/LPM-23-NoiseGate.PDF

here is another: http://hammer.ampage.org/files/GainesNoiseGate.PDF

[ragtime8922]

http://yfrog.com/j3mxrnoisegatev1g
MXR v1


http://yfrog.com/14mxrnoisegatev2j
MXR V2

[ragtime8922]

MXR V2


MXR V1

[elfito]

here is one: http://hammer.ampage.org/files/LPM-23-NoiseGate.PDF

here is another: http://hammer.ampage.org/files/GainesNoiseGate.PDF

the LPM-23 seems like a fun pedal tyo build
but it have those weird diodes ,is there any substituts for the values?

[Mark Hammer]

1N914 or 1N4148

[El Heisenberg]

So the only difference between the two MXR noise gates are the FET arrangement?? What's the big difference in sound/performance??

I didn't know there were 2 versions. I'm pretty sure I built the version 1. But I also followed the tonepad schematic. Dunno if the tonepad one was version 1 but I compared the schems and didn't remember seeing anything diffrent. But the version 2 schem posted here IS different.


Had no idea there were so many noise gates. That chinese one would be a good build if I made the PCB. The chinese schematic is hard to read, so I wouldn't be able to perf it.  there's also this 4016 design:








But what I really wanna build is the DOD fx30 since I already have a working MXR noise gate built.


http://www.freeinfosociety.com/electronics/schemview.php?id=343

Anyone built this??

[Mark Hammer]

There is a certain level of complexity which you can't dip below, when it comes to noise control, unless you subcontract all the complexity out to a dedicated chip designed to do it.  You will always need some attenuation element, whether FET or optoisolator, or OTA, and you will always need a rectifier to track the input signal, and you will always need some sort of gain stage to drive the rectifier.  Everything beyond that is simply bells and whistles to make each element behave better

The Japanese schematic I posted is actually not all that complicated or exotic.  The 2SC1000 trannies can be subbed with 2N5088s (watch out for the pinout differences), the 1S1555s can be 1N914s, and the LM324 can be a TL074 without any problems arising (though this would not improve performance in any way).  The Zener is just any old 5.1V zener, and the K30A is reasonably available, though you can probably sub a 2N5457 for it if you need to.

The JFET is used as a voltage-controlled resistor, in parallel with the 470k fixed resistor.  Between their combined parallel resistance, and the 10k resistorin the signal path just ahead of them, they form an attenuator/voltage-divider.  When the JFET is turned on, the combined parallel resistance of the JFET and 470k drops, and they attenuate the signal.  The extent to which the signal is attenuated is a function of the 10k and 470k resistors.  If the 470k is decreased to, say 220k, then the drop in combined resistance produced when the JFET goes low is not that big a change from the resting state.  Same thing if the 10k resistor is increased to 47k.  If that "input leg" of our virtual pot has a greater resistance, then the "ground leg" formed by the 470k and JFET has to drop wayyyyyy down to produce a big change in attenuation.  Conversely, if we change the 10k to 2k2, then it will take a huge change in JFET resistance to produce dramatic attenuation.

All of this is to say that you can tinker with the amount of attenuation produced by playing with either the value of the 10k, the value of the 470k, or both.

Much like the Dynacomp/Ross compressor, and all variants, the 1M Decay pot over on the right determines how long it takes to recharge that 10uf cap.  Large series resistance between B+ and the + end of that cap means that current trickles in, rather than rushes in, so it takes longer to recharge the cap.  The JFET is set to low resistance (i.e., the signal is "gated" off) when that cap is fully charged.  So, the slower the recharge time, the longer the signal hangs around before the circuit cuts it out completely.

A gate with a variable decay time, and adjustable attenuation, will provide reasonably satisfactory performance over a fairly broad range of circumstances.  If the threshold control is .twitchy", then let us know and some component-value adjustments can be made to improve the dialability.

Finally, please note that when I scanned the project article, I made no attempt to assure the scale.  Plus, the layout is not flipped around in anticipation of PnP.  You will likely have to do a screenshot of the layout, and then flip it over and resize, in whatever your graphics application of choice happens to be, before committing to a toner transfer.

[Brymus]

here is one: http://hammer.ampage.org/files/LPM-23-NoiseGate.PDF

here is another: http://hammer.ampage.org/files/GainesNoiseGate.PDF

Those are both cool,I love the humor in the Japanese version,and the use of stars in the PCB.
Mark If I were to clean up the overlay and transfer to the Gains circuit would you look it over prior to me etching and wiring it up?
I am itching to etch something and need a noise gate.
Bryan

[Brymus]

Here how does this look?
Cleaned up and mirrored,print scaling I am not sure about that may need a little work.

[moosapotamus]

Here's another one for the schematics collection... Haven't tried it but it does look pretty simple, very low parts count and one knob control...
Eingang = Input
Ausgang = Output



I like the look of the Gaines NG, too. Full compliment of controls plus a key input. I could probably use a decent NG, myself.
So, I whipped up an overlay, which usually helps me keep things in order when stuffing a board.



I'd probably replace the switch for the key input with a switching jack instead, just to avoid taking up space on the front panel. If I find time, I might even take a swing at redoing the layout to include a LT1054 (to handle the bipolar supply) and to make it fit vertically in a 1590BB enclosure.

~ Charlie

[Mark Hammer]

Like ANYthing with a sidechain, "feel" is important.  And when it comes to sidechain-controlled devices, "feel" = time constants and the match of the time constants to the signal source and context.  What makes for super gating of a kick drum, and helping to keep bleedthrough of amps to the drum mic when the drummer isn't hitting the kick drum, may be absolutely intrusive and interfering when it comes to a guitar.

Why am I telling you this?  Because it is highly unlikely that a "simple" noise gate circuit will provide pleasing performance for a guitar unless it was deliberately designed for guitar from the ground up.  So, in the circuit Charlie posted, will C3 provide the "right" decay characteristics? does the gain of T1 and the attenuation provided by R3 correspond to the range of signal levels a guitar presents? will T3/R5 provide the optimal amount of attenuation?  We don't know.

This is not a scolding.  Rather, like I say, whenever you're dealing with somethng whose functioning depends on the use of a detected signal envelope to manage a heard signal envelope, you cannot depend on any single detection circuit to yield the heard envelope you're looking for.  The posted circuit may be absolutely what the doctor ordered for managing noisy backgrounds using a ham or CB radio carbon or crystal mic, but be entirely inappropriate for other uses.

As always, keep your expectations realistic.

[moosapotamus]

Thanks for the caveats, Mark.
I really only posted that one because the OP was looking for "simple". But I also stated that I had not built it so, yeah... [grain of salt].
Looks simple enough to breadboard relatively quickly, so it still might be worth a shot. Conceptually, I like the simplicity of the single control knob.

I am also thinking about building the Gates circuit, too.

~ Charlie

[Scruffie]

The DOD 230 is a really nice looking simple build and was designed for guitar as far as I know, i'm just about to build one up soon but from all reviews, seems to serve its purpose well and it's a nice easy optocoupler build so you just have to get an LDR that has a fast decay... seems to be pretty much that simple, no trim pots, anything and easily available values and just 2 Dual Op-Amps.

So although I haven't technically built it yet... it still gets my vote.

[Mark Hammer]

Like I keep saying, the dissatisfaction many have with noise gates is because they expect too much out of a single unit, obliging it to take care of too many "noise crimes".  However, if you have a pair of them - one near the start and one near the end of your pedal chain - you can set them for gentler action such that they interfere with your sound less.

One of the great things about going DIY is that you can throw together more than one copy of a given circuit relatively inexpensively.  This is one of those cases.