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DIY Stompboxes => Building your own stompbox => Topic started by: Steve Mavronis on November 13, 2010, 03:43:26 PM

Title: DIY Noise Suppressors
Post by: Steve Mavronis on November 13, 2010, 03:43:26 PM
What 'classic vintage pedals' are the favorite DIY noise suppressor projects based on? For a 3rd project (after I finish my compressor clone) I'm looking for something again not too complicated circuit-wise if possible, that does noise filtering when not playing and doesn't have that annoying 'noise creep' while playing longer duration notes. I'm using a Boss NS2 which works as advertised, but the thing I really hate is that noise fizzle effect that creeps its way back to the tail end of notes while playing. Is there any way to also filter that out that noise creep without cutting off note duration in a DIY project? Can the noise frequencies be simultaneously 'split off' while notes are being played and discarded?
Title: Re: DIY Noise Suppressors
Post by: Mark Hammer on November 14, 2010, 09:26:35 AM
Quote from: Steve Mavronis on November 13, 2010, 03:43:26 PM
What 'classic vintage pedals' are the favorite DIY noise suppressor projects based on? For a 3rd project (after I finish my compressor clone) I'm looking for something again not too complicated circuit-wise if possible, that does noise filtering when not playing and doesn't have that annoying 'noise creep' while playing longer duration notes. I'm using a Boss NS2 which works as advertised, but the thing I really hate is that noise fizzle effect that creeps its way back to the tail end of notes while playing. Is there any way to also filter that out that noise creep without cutting off note duration in a DIY project? Can the noise frequencies be simultaneously 'split off' while notes are being played and discarded?
In general, the answer is "No", "Maybe", and "It depends".

Most users of noise gates and filters have a high degree of dissatisfaction with them, for precisely the same reasons that you note.  My own take on it is that this happens because use of a single noise-reduction pedal in one position requires it to do far too much.  Superior performance would occur if one used a pair of noise-reducers - one at the beginning and one at the end of a pedal chain - such that each could be used in a less heavy-handed, and more targetted, way.

The central problem is that "noise" covers a very broad range of phenomena and spectral content...and of course, sadly for us, so does the guitar signal.  The majority of noise-reduction devices rely on using the level of the overall signal (guitar + noise) to differentiate between wanted and unwanted.  And since there is often not much difference between the level of all accumulated noise, and the tail end of a soft note, it will cut the note tail as it chops out the noise.

In my view (and one I've posted here on many an occasion), a far better approach to noise-management of guitar signal paths is to use one noise-reduction device at the head of your signal chain, immediately after the guitar (or darn close to that position), which explicitly targets hum.  Early in the signal chain, there is precious little hiss, such that a device which exclusively targets that objectionable low-frequency hum and buzz can be quite effective without having to impact on the brunt of the signal.  One might experience a wee bit of bass loss, but the rest would come through ably.  Since that hum at source will not be magnified by passing through assorted gain stages, by the time your signal gets to the last cable to the amp, there should be precious little hum to contend with.

What does accumulate through your pedal chain is hiss, particularly in those pedals that apply large amount of gain.  If all you're forced to deal with, at the, end is hiss then it becomes easier to manage via a simple sliding low-pass filter.  Moreover, any side-chain used to drive the filter can focus pretty much exclusively on the envelope of content above, say, 3000hz or so to determine whether action needs to be taken.

Ultimately, when it comes to noise, divide and conquer.  If one plans to use a single pedal to manage noise, then it's plug in and grumble.

And, as I always do, I'll put in a little plug for the excellent noise-reduction properties of the SSM2166 chip.  It not only provides hiss-free compression, but can clean up the signal nicely for the rest of your pedals, requiring only very light gating at the end of the chain to manage cumulative hiss.
Title: Re: DIY Noise Suppressors
Post by: amptramp on November 14, 2010, 09:50:35 AM
One hobby of mine is to collect and restore antique radios.  One radio I have, an RCA A-33 has an interesting noise reduction scheme: it reduces the treble for low signal levels.  It does this by using a reactance tube as part of an audio filter and detecting the average signal level and using it to control the gain which in turn controls the effective capacitance and reduces the high-frequency rolloff for low signal levels to reduce noise.  There have been a number of similar "single-ended noise suppression" circuits (as opposed to double-ended circuits like Dolby that record the music in a predistorted format that is then corrected in the playback end).  A voltage-controlled filter is a standard building block for analog synthesizers and it may do what you want.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 14, 2010, 10:05:05 AM
Thanks guys for the above viewpoints. I'm curious of various strategies employed by companies like Boss and MXR to deal with noise. Boss having an effects loop built into their NS2, which for my meager setup of one dirt pedal doesn't seem to help much. Can anyone compare for me the diference between the 80's MXR Noise Gate and today's MXR Smart Gate? The newest MXR Smart Gate also has an extra filter switch for different ranges of noise (hiss, mid, full) but is it effective?

http://www.jimdunlop.com/index.php?page=products/pip&id=255

I was trying to explain the noise fade-in while playing issue to my father the electronics design guru. He thinks there could be a way to design a better noise reduction circuit to handle this problem but that may be wishful thinking until we experiment. That's why I'm curious if the extra MXR Smart Gate features works a little better than the Boss NS2 in this respect?
Title: Re: DIY Noise Suppressors
Post by: Scruffie on November 14, 2010, 10:30:46 AM
Best I can manage is a list of possible projects that I know of :-
Tonepad MXR - Noise Gate V1 & 2 (as you already seem to know)
DOD - 230 Noise Gate
EHX - The Silencer
BOSS - SG-1 (Not a gate in the usual sense but It did work to cut out noise with the controls down so it didn't swell and it is a gate in design so i'll include it)

This thread might be of some use - http://www.diystompboxes.com/smfforum/index.php?topic=81918.0
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 14, 2010, 10:47:54 AM
Thanks for that link and did you ever build a DOD 230 and if so how is it?

To further illustrate the problem I'm annoyed with watch this YouTube video of Yngwie Malmsteen giving a backstage dressing room lesson:

http://www.youtube.com/watch?v=hLa6iW7dRf4

At the end of some riff examples he plays you can hear the Boss NS2 noise sizzle enter the mix on the last note if it's held a bit longer. I'm not sure if the very first one when he goes "whoa" is this or not but if you listen closely to later examples you can subtly detect it at the end of passages.
Title: Re: DIY Noise Suppressors
Post by: Scruffie on November 14, 2010, 10:56:44 AM
I'm just waiting on the Opto to come in the post at the moment, but from all reviews - http://www.harmonycentral.com/products/93077
Seems like a good pedal, can't get much simpler and there's already a nice Onboard pot layout about for you  ;)

Yeah alot of people like the NS-2... I am not one of those people... the 230 is a gate as opposed to a supressor so the shut off should mean it wont fizzle out slowly.
Title: Re: DIY Noise Suppressors
Post by: slacker on November 14, 2010, 11:10:59 AM
Simplest noise gate in the world and very effective is pinky and volume knob :)

Do you mean the noise effect at around 23 seconds? I don't think there's much you can do about that, that's caused because he's stopped playing and muted the strings so the noise gate does what it's supposed to and lowers the volume, so you hear a bit of the hiss and then it mutes it. You could speed up the decay time, but then you run the risk of cutting off the end of the notes. This goes back to what Mark said about the level of the signal being too close to the level of the noise.
What would be better in my opinion would be to not completely mute the noise just reduce it to an acceptable level, that way the effect wouldn't be so obvious.
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 14, 2010, 11:19:45 AM
Quote from: slacker on November 14, 2010, 11:10:59 AM
Simplest noise gate in the world and very effective is pinky and volume knob :)



+1 on that....or use a different gain pedal, that doesnt hiss like *#^"...

volume pedal is cool too...especially the ones with the level knob..

it can be set to be overdriven to full on gain for solo's depending on setting, no need for pinky's either. :icon_wink:
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 14, 2010, 12:46:20 PM
All dirt pedals add noise so that's a given. At least my DIY 250 clone is 'less' noisey than the YJM308 that I was using and without the excess treble too. I love the midrange overdrive tone however so I'm sticking with that. I think my standard Strat stock single coil pickups are causing most of the problem plus the AC outlet 60 cycle hum is a big factor too. The in-between pickup positions are quiet acting like a humbucker canceling guitar noise. The NS2 does a good job except for the noise fade-in at the end of notes. I'm just wondering how noise suppressor circuits could be improved somewhat through DIY pedal building. I'm trying to determine if I were to base a clone on a vintage noise gate/reduction type pedal if it would be worth it especially if the end result is the same as what I've got.
Title: Re: DIY Noise Suppressors
Post by: Scruffie on November 14, 2010, 12:48:12 PM
Quote from: Steve Mavronis on November 14, 2010, 12:46:20 PM
All dirt pedals add noise so that's a given. At least my DIY 250 clone is 'less' noisey than the YJM308 that I was using and without the excess treble too. I love the overdrive tone however so I'm sticking with that. I think my standard Strat stock single coil pickups are causing most of the problem plus the AC outlet 60 cycle hum is a big factor too. The in-between pickup positions are quiet acting like a humbucker canceling guitar noise. The NS2 does a good job except for the noise fade-in at the end of notes. I'm just wondering how noise suppressor circuits could be improved somewhat through DIY pedal building.
If it's your single coils I can't reccomend shielding your guitar enough, my shielded strat is completely silent, not a bit of hum on it.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 14, 2010, 12:50:37 PM
Quote from: Scruffie on November 14, 2010, 12:48:12 PM
If it's your single coils I can't reccomend shielding your guitar enough, my shielded strat is completely silent, not a bit of hum on it.

I know it's a separate topic but how did you shield your strat better?
Title: Re: DIY Noise Suppressors
Post by: Scruffie on November 14, 2010, 12:55:23 PM
Quote from: Steve Mavronis on November 14, 2010, 12:50:37 PM
Quote from: Scruffie on November 14, 2010, 12:48:12 PM
If it's your single coils I can't reccomend shielding your guitar enough, my shielded strat is completely silent, not a bit of hum on it.

I know it's a separate topic but how did you shield your strat better?
http://www.guitarnuts.com/wiring/shielding/shield3.php
Star grounding, copper shielding (aluminium will be fine, I just used it as you can solder it) and also, some very basic protection from tube amp failure which isn't usually offered  :)
Title: Re: DIY Noise Suppressors
Post by: Joe Hart on November 14, 2010, 12:59:28 PM
Quote from: deadastronaut on November 14, 2010, 11:19:45 AM
Quote from: slacker on November 14, 2010, 11:10:59 AM
Simplest noise gate in the world and very effective is pinky and volume knob :)

+1 on that....or use a different gain pedal, that doesnt hiss like *#^"...
volume pedal is cool too...especially the ones with the level knob..
it can be set to be overdriven to full on gain for solo's depending on setting, no need for pinky's either. :icon_wink:

I agree with the volume knob thing -- I use it ALL the time (mostly to kill feedback and string noise).  I also do the volume pedal thing.  I use it a lot for cutting out noise (and silent tuning).  But I totally disagree with the "use a different gain pedal" comment.  I have a humbucker equipped guitar that is pretty dang quiet, into (among other things) a wah and a DOD 250 clone and LOVE my tone!  I've tried different distortion pedals and nothing really gets me the sound I want.  And with the wah and 250 on, it's noisy, but I deal with it.

I think Steve may be simply looking for something that will fix a problem he (and many others) is having.  Nothing wrong with that.
-Joe Hart
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 14, 2010, 01:05:16 PM
Quote from: Joe Hart on November 14, 2010, 12:59:28 PM
I totally disagree with the "use a different gain pedal" comment.  I have a humbucker equipped guitar that is pretty dang quiet, into (among other things) a wah and a DOD 250 clone and LOVE my tone!  I've tried different distortion pedals and nothing really gets me the sound I want.  And with the wah and 250 on, it's noisy, but I deal with it. I think Steve may be simply looking for something that will fix a problem he (and many others) is having.  Nothing wrong with that.

Yeah, in loving your dirt pedal of choice (gray spec 250 Overdrive in our case) you accept the added noise it brings and the NS2 noise gating part is fine. I'm just trying to see if it's possible to filter out as much 60 hertz noise amplification fading back in while you're playing when it's not being gated.
Title: Re: DIY Noise Suppressors
Post by: petemoore on November 15, 2010, 07:18:42 AM
  Kindly spoken, I can see where a noise suppressor could be useful.
  For these situations I use a bypass switch.
  If high gain / compression is used, by definition any input [including noise] is boosted to 'max' or close enough that noise is suffieciently ugly to consider Supressor circuit.
  Transition between 'closed' and 'play', when noise is 'maxxy' will tend to confuse the threshold detector if any playing dynamics include low-volume passages as signal volume you want to hear is less than the noise.
  A 'blip' of noise of course will get through as it 'turns on', I've heard this used in a musical-modern-metal way or as added unwanted punctuations to the music.
  Another approach is: get rid of noise and keep dynamics [eliminate ground loops, continue to peel the onion layers of noise reduction, cry between each layer],
  Perhaps a sound from a circuit that 'naturally gates' can be found, exhibiting the ability to have its gate stage rammed with enough input that when played, it is driven 'open' predictably. 
 
 
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 08:04:58 AM
wrong post, thought you wanted a noise gate...nevermind :icon_rolleyes:

btw arent 741's inherently noisey?...i read that on a few sites..,

Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 08:58:31 AM
Yes they are noisey in that they gain amplify everything going through them, your guitar signal and any 60 cycle hum and pickups or anything else before them, etc. The point is the noise "fades" back into the signal from the NS2 with a sizzle effect. Before that, for a moment, it's a nice "noise reduced" 741 overdrive sound. The 741 is amplifying the noise not being filtered out going into it. I know there are many who say the 741 has been around too long and there are better modern op amps. So why clone vintage pedals at all? Because with all its issues the modern stuff just doesn't capture the so-called grail tone based on days of old that we are after. Do you know any distortion pedal (or amp?) that doesn't amplify noise as you increase the gain? I get the same noise suppressor annoyance with other dirt pedals like the DOD YJM308, Boss DS1, and the old Ross R50 Distortion - none of them use a 741 op amp. So it's not purely a "741 issue" or let's all play clean amp tones or acoustic guitar and not use any noise suppressor at all. I find it interesting though that even the 70's/80's MXR Noise Gate used two 741's in it's circuit.
Title: Re: DIY Noise Suppressors
Post by: anchovie on November 15, 2010, 09:34:06 AM
Quote from: Steve Mavronis on November 15, 2010, 08:58:31 AM
I find it interesting though that even the 70's/80's MXR Noise Gate used two 741's in it's circuit.

The clue is in the name - it's a gate, so it mutes the output when the input signal falls below the threshold setting. Doesn't matter so much if the 741 adds a tiny bit of hiss to your full-whack overdrive sound!

Steve - I'm guessing that you've played around with your NS-2's threshold, decay and mode controls and you find that you either get the sizzle or get cut off too abruptly. There is a point on note fade-out where your vibrating string becomes roughly the same amplitude as the buzz from your single coils. I don't think the NS-2 (or most noise gate/suppression pedals) is clever enough to know which is which. I think your choices may well be to take the sizzle, take the abrupt cut, try out a Decimator/other fancy rack unit in a shop or look into shielding your Strat and/or replace the pickups with noiseless single coils or stacked humbuckers. I appreciate that my own personal approach of playing with so much distortion and volume that held notes will feed back until I switch off the dirt box isn't for everyone.

At least you can take it as a consolation that you have video evidence of the problem happening to Yngwie!
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 09:36:51 AM
Yep. That's why I'm also interested in the new MXR Smart Gate with the selectable 3 band hum/mid/full noise filtering added feature. Maybe having the addition of that extra filtering would help out for this kind of issue as a DIY project.
Title: Re: DIY Noise Suppressors
Post by: EATyourGuitar on November 15, 2010, 09:40:48 AM
don't take offense cause I speak the truth. 99% of guitar players would rather buy a pedal than open a book and read about proper shielding, impedance, proper grounding, grounding safety, low capacitance cables, non microphonic cables, signal to noise ratio, nominal level, etc... I saw one person that said anything to this affect. yes shield your strat, please. if your using a crappy guitar cable, and most guitar players do, get a good one. if its cheaper than $40 for a 15ft than its probably not what you want on a $800 guitar. I will kick it too you like this, a guitar with no noise problem and no noise supresser will always, always sound better than a noisy guitar with a couple noise supressors thrown in the chain. every electrical component adds noise. so for every step forward, you take a step back. although the gentlemen was right that high gain pedals raise your noise floor. so I can see why putting right after the guitar makes sense. also, the sidechaining question depends on what noise your trying to filter out. if you plan to only use the pedal in the usa you can target the 60hz band with a bandpass filter or notch filter. depending on how complicated you want it to be. like you can isolate your 60hz signal and invert it with an inverting opamp, then mix it into the guitar signal. the 180 degree out of phase 60hz signal cancels out the one your hearing. I would not buy a pedal but if you must, the ISP decimator has a setting for 60hz.
Title: Re: DIY Noise Suppressors
Post by: anchovie on November 15, 2010, 09:47:59 AM
Quote from: Steve Mavronis on November 15, 2010, 09:36:51 AM
Maybe having the addition of that extra filtering would help out for this kind of issue as a DIY project purchase.

If you have a player's need for this, save yourself a big headache.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 09:58:16 AM
Quote from: anchovie on November 15, 2010, 09:47:59 AM
If you have a player's need for this, save yourself a big headache.

It's not a super big deal just an annoyance I'm living with. Except for the time and effort to make a DIY pedal, I'd end up spending $50 instead of $110 for a new one and there is a certain personal satisfaction ending up with a working DIY project you've built yourself. That's the real fun part that makes all the trouble worth it. I'm just curious and glad you guys are throwing in your ideas and suggestions to help understand the nature of the problem. Re-thinking an issue is always a good thing because you learn and gain experience.

Actually this is an idea for a possible future project. I need to finish my current compressor clone first and I probably should build myself a small pedalboard next anyways.
Title: Re: DIY Noise Suppressors
Post by: Ben N on November 15, 2010, 10:07:39 AM
FYI, Steve, what Boss refers to as an "Effects Loop" in its noise suppressor pedals is really something else: a side-chain controlled gate. The idea is that, as noted above, it can get tricky trying to set a threshold level for the gate that both stops hiss and lets low level signals pass, since the noise floor is often as high as your signal tails. If you set the threshold at the level of the noise floor, you lose the signal tails; if you set it lower, you accomplish nothing. What the Bosses do is track your signal before your fx add all that extra content (aka hiss). Assuming there is no hum and your pre-effects signal is pristine and noiseless (not a small assumption for single coils, to be sure), if you use the pre-effects signal to trigger the gate, you can set the gating threshold low enough to let (nearly) all of your signal through. However, you apply the gating effect after your noisy effects. You don't have to use it, but it does make the pedal a bit more effective, although it doesn't quite cure the ways in which noise suppressors endemically mess with your signal.
If you were to look at an NS-2 schematic, the "input" feeds a buffered splitter. Half of the splitter's output goes to the envelope follower, and the other half goes to the Send jack. All if the actual noise suppression takes place between the Return jack and the output.
If you wanted to use an NS-2 for hum suppression, you would do it without the fx loop. I don't know how well that would work, though. If you wanted to filter the envelope signal, you could use an external buffer-splitter to feed your filtered sidechain signal to the main input (which is really the sidechain) and your main signal to the Return jack.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 10:12:00 AM
Thanks Ben. I do use the effects loop currently:

(http://home.comcast.net/~snmavronis/mypedalchain.jpg)

Let me experiment without the loop just in case. Actually Yngwie doesn't use the loop feature at least according to another video where he shows how it kills the hum.

I don't want to build a DIY pedal if I'd just end up with the same result or something worse.
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 11:14:30 AM
yeah! lets all have clean guitars instead... :icon_wink: :icon_mrgreen:

Title: Re: DIY Noise Suppressors
Post by: EATyourGuitar on November 15, 2010, 11:28:15 AM
Quote from: deadastronaut on November 15, 2010, 11:14:30 AM
yeah! lets all have clean guitars instead... :icon_wink: :icon_mrgreen:

do you know what white noise sounds like? do you know what it sounds like to have all your pick attack swallowed up by high capacitance cables? you always hear guitar players with nice equipment talk about "tone". well thats all it is. low capacitance, good frequency response, good signal to noise ratio. there is a big difference in adding even order harmonics or saturation to a signal and just flooding it with white noise. any distortion pedal can be broken down into simple science. its just a combination of EQ's, Compressors, more EQ's, wave shaping/wave folding.more EQ's. thats all it is. when you achieve that without the whitenoise and 60 cycle hum, you have your "tone". I'm not saying you have to play clean. thats just ignorant. famous people have paid guitar techs. if your not famous then maybe you should want to learn this stuff and do it your self the right way.
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 11:37:08 AM
Quote from: EATyourGuitar on November 15, 2010, 11:28:15 AM
Quote from: deadastronaut on November 15, 2010, 11:14:30 AM
yeah! lets all have clean guitars instead... :icon_wink: :icon_mrgreen:

do you know what white noise sounds like? do you know what it sounds like to have all your pick attack swallowed up by high capacitance cables? you always hear guitar players with nice equipment talk about "tone". well thats all it is. low capacitance, good frequency response, good signal to noise ratio. there is a big difference in adding even order harmonics or saturation to a signal and just flooding it with white noise. any distortion pedal can be broken down into simple science. its just a combination of EQ's, Compressors, more EQ's, wave shaping/wave folding.more EQ's. thats all it is. when you achieve that without the whitenoise and 60 cycle hum, you have your "tone". I'm not saying you have to play clean. thats just ignorant. famous people have paid guitar techs. if your not famous then maybe you should want to learn this stuff and do it your self the right way.

whooaah..back up there!.before you call me ignorant... maybe you should read the thread again ... that wasn't aimed at you...steve said it ok.......
now take your time and learn to read/aim.before you fire ok...or do you have to be famous to read as well?........... :icon_rolleyes:
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 11:44:50 AM
Quote from: Steve Mavronis on November 15, 2010, 08:58:31 AM
Yes they are noisey in that they gain amplify everything going through them, your guitar signal and any 60 cycle hum and pickups or anything else before them, etc. The point is the noise "fades" back into the signal from the NS2 with a sizzle effect. Before that, for a moment, it's a nice "noise reduced" 741 overdrive sound. The 741 is amplifying the noise not being filtered out going into it. I know there are many who say the 741 has been around too long and there are better modern op amps. So why clone vintage pedals at all? Because with all its issues the modern stuff just doesn't capture the so-called grail tone based on days of old that we are after. Do you know any distortion pedal (or amp?) that doesn't amplify noise as you increase the gain? I get the same noise suppressor annoyance with other dirt pedals like the DOD YJM308, Boss DS1, and the old Ross R50 Distortion - none of them use a 741 op amp. So it's not purely a "741 issue" or let's all play clean amp tones or acoustic guitar and not use any noise suppressor at all. I find it interesting though that even the 70's/80's MXR Noise Gate used two 741's in it's circuit.

ok?.... :icon_rolleyes:
Title: Re: DIY Noise Suppressors
Post by: Mark Hammer on November 15, 2010, 11:51:55 AM
Quote from: Ben N on November 15, 2010, 10:07:39 AM
FYI, Steve, what Boss refers to as an "Effects Loop" in its noise suppressor pedals is really something else: a side-chain controlled gate. The idea is that, as noted above, it can get tricky trying to set a threshold level for the gate that both stops hiss and lets low level signals pass, since the noise floor is often as high as your signal tails. If you set the threshold at the level of the noise floor, you lose the signal tails; if you set it lower, you accomplish nothing. What the Bosses do is track your signal before your fx add all that extra content (aka hiss). Assuming there is no hum and your pre-effects signal is pristine and noiseless (not a small assumption for single coils, to be sure), if you use the pre-effects signal to trigger the gate, you can set the gating threshold low enough to let (nearly) all of your signal through. However, you apply the gating effect after your noisy effects. You don't have to use it, but it does make the pedal a bit more effective, although it doesn't quite cure the ways in which noise suppressors endemically mess with your signal.
If you were to look at an NS-2 schematic, the "input" feeds a buffered splitter. Half of the splitter's output goes to the envelope follower, and the other half goes to the Send jack. All if the actual noise suppression takes place between the Return jack and the output.
If you wanted to use an NS-2 for hum suppression, you would do it without the fx loop. I don't know how well that would work, though. If you wanted to filter the envelope signal, you could use an external buffer-splitter to feed your filtered sidechain signal to the main input (which is really the sidechain) and your main signal to the Return jack.
Just to clarify, ALL noise gates have a "sidechain", with differences in their complexity, and how the envelope information is extracted and applied.  Where they often differ is in where that sidechain ends up doing the detecting, and where it is being applied.

The nice thing about the NS-2 and similar kinds of pedals with a send/return loop is that the envelope information can be extacted from one place, and applied at another.

Why is this good?  Well, for one thing, since all such devices use the amplitude information to differentiate between wanted and unwanted signal, it helps immensely, with respect to precision and reliability, if that amplitude information is obtained at the junction where the difference between guitar signal and noise is greatest.  As the signal passes through subsequent pedals, these will often impose some compression and restriction of dynamic range.  Meanwhile, the noise level gradually gets added to, and the difference between the noise and the signal (particularly the decay phase where the difference between those last few breaths of the string and the noise is small) gets smaller.  It becomes harder to dial in the "right" threshold point where the gate needs to kick in.

By situating the detection part of the pedal (the sidechain) at the start where distinguishing signal from noise is easiest, and applying that sidechain information later in the chain (where theaccumulated noise poses greater risk), the noise-reduction action can be made more effective.

At least more effective from the perspective of using one pedal.
Title: Re: DIY Noise Suppressors
Post by: Fuzz Aldryn on November 15, 2010, 01:22:32 PM
Quote from: EATyourGuitar on November 15, 2010, 09:40:48 AM
[...] if its cheaper than $40 for a 15ft than its probably not what you want on a $800 guitar. I will kick it too you like this, a guitar with no

Nonesense! If somebody offers you a good quality cable for more than 40 bucks he's probably a thief! I totally agree with the fact of using good quality cables but not with the prices you mention here. That's something you can probably propagate on the gear page forum where most of the people can't  handle a solderiron but not here!
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 01:31:01 PM
Quote from: deadastronaut on November 15, 2010, 11:44:50 AM
Quote from: Steve Mavronis on November 15, 2010, 08:58:31 AM
Do you know any distortion pedal (or amp?) that doesn't amplify noise as you increase the gain? I get the same noise suppressor annoyance with other dirt pedals like the DOD YJM308, Boss DS1, and the old Ross R50 Distortion - none of them use a 741 op amp. So it's not purely a "741 issue" or let's all play clean amp tones or acoustic guitar and not use any noise suppressor at all.

ok?.... :icon_rolleyes:

That "bolded" phrase, but also including the beginning of the sentence it is in, was meant as sarcasm response to your slamming a 741 based dirt pedal as the main cause of the white noise hiss or hum that I'm getting. I was thinking like I might as well give up rock guitar and go acoustic if that were really true! ;)

Cable-wise I'm using Ibanez Series DS Low Noise Cables and a Fender low noise cable long enough for the effects loop return. Half my issue is probably the stock standard strat single coil pickups. I can cut the noise by using the in-between 2 and 4 pickup selection with the switch. Positions 1, 3, and 5 are noisey.
Title: Re: DIY Noise Suppressors
Post by: EATyourGuitar on November 15, 2010, 01:57:21 PM
Quote from: deadastronaut on November 15, 2010, 11:44:50 AM
ok?.... :icon_rolleyes:
my apolagies, I thought you were mocking me since it was right under my post.

and yes you can make your own neutrik + mogami or neutrik + evidence. but who wants to go through all that for one cable. I paid $18 for a $55 mogami and it still has the lifetime guarantee. only because I worked at that horrible horrible place that starts with a G and a C. I agree that the cables aren't worth it at a retail store but there isn't much alternative if you want that exact mogami cable.
Title: Re: DIY Noise Suppressors
Post by: Gordo on November 15, 2010, 02:08:33 PM
Steve, I think you may find it's a combination of all the above answers.  Because I'm hopelessly addicted to building pedals I tend to tailor my board to the tunes I'm playing or the amp rig.  The one consistent pedal that's helped though is the single knob Decimator.  I'd be the last one to tell you to BUY a pedal rather than MAKE one but I think the ISP technology is beyond our scope.  Shielding your strat will help, but marginally.  I use a few single coil guitars and I get used to riding the volume or kicking out a noisy pedal between tunes.  Once the band is playing it's a moot point unless the noise is REALLY loud.  The decimator doesn't seem to bugger up my tone (I do a pretty good job of that myself), and you don't get the noticeable fluttering decay that most gates have.  I seem to recall the MXR original white one was the worst.  I gave up on my Tonepad version.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 02:15:11 PM
Thanks all and sorry for any misunderstandings. I'm going to re-evaluate my setup because maybe I'm nitpicking over nothing to be concerned about. I'm not in a band and I just practice at home so maybe I'm noticing too much by listening to every nuiance.
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 02:17:34 PM
Quote from: Steve Mavronis on November 15, 2010, 01:31:01 PM
Quote from: deadastronaut on November 15, 2010, 11:44:50 AM
Quote from: Steve Mavronis on November 15, 2010, 08:58:31 AM
Do you know any distortion pedal (or amp?) that doesn't amplify noise as you increase the gain? I get the same noise suppressor annoyance with other dirt pedals like the DOD YJM308, Boss DS1, and the old Ross R50 Distortion - none of them use a 741 op amp. So it's not purely a "741 issue" or let's all play clean amp tones or acoustic guitar and not use any noise suppressor at all.

ok?.... :icon_rolleyes:

That "bolded" phrase, but also including the beginning of the sentence it is in, was meant as sarcasm response to your slamming a 741 based dirt pedal as the main cause of the white noise hiss or hum that I'm getting. I was thinking like I might as well give up rock guitar and go acoustic if that were really true! ;)

Cable-wise I'm using Ibanez Series DS Low Noise Cables and a Fender low noise cable long enough for the effects loop return. Half my issue is probably the stock standard strat single coil pickups. I can cut the noise by using the in-between 2 and 4 pickup selection with the switch. Positions 1, 3, and 5 are noisey.

@eatyourguitar..no worries dude!.

@steve, hold on , so was mine..thats why i had a wink/laugh on it ok.....
im not bent on slamming anything, i was just saying that's what ive read, and there is plenty of info to confirm this
obviously your very precious about it, which is understandable,considering the amount of precise work you put in to copy/improve
it, .
i didnt design the 741....or the noise suppressor...im not hear to criticise any pedal, just thought id throw my 2p worth in...
(which is obviously not welcome)..
good luck and hope you get the answers you need/want ok. :icon_wink:
all the best. rob.........
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 15, 2010, 02:20:35 PM
No problem, your comments are always welcome. Lots of winkies today but all in fun ;)
Title: Re: DIY Noise Suppressors
Post by: deadastronaut on November 15, 2010, 02:26:38 PM
ok  heres one more then for ya ok... :icon_wink:

Title: Re: DIY Noise Suppressors
Post by: merlinb on November 15, 2010, 02:59:01 PM
Most commercial pedals -and practically all DIY pedals- are atrociously noisy. Real audio engineers would faint (or laugh) if they saw the circuits. No one seems to notice though, until you start string 5-10 of them in series, at which point you end up needing a noise gate.
If people designed pedals properly to have less series resistance throughout the circuit, high input impedance, low output impedance, FET opamps etc. then noise reduction would rarely be required.
Title: Re: DIY Noise Suppressors
Post by: Mark Hammer on November 15, 2010, 03:19:58 PM
"Noise" = everything that is not my guitar signal the way I want it.

In that sense, it is a bit like "foreigners", and subsumes many different forms and origins.  Expecting "noise" to be tamed in total at one locus makes as much sense as having a translator for one single language at all airport immigration sites and all courts and other public services.

Yes, decent shielding, hum-rejecting pickups, "better" components, and such are all part of it, but so are other things (e.g., BBD clock noise, digital heterodyning, charge pump whine, ground loops, etc.) .  I will maintain to my dying day that, if we are working in the analog domain, NOTHING inserted at one point in the signal path is going to be able to tackle everything that counts as "noise", and any claims of single solutions are sheer folly.
Title: Re: DIY Noise Suppressors
Post by: Scruffie on November 15, 2010, 06:03:15 PM
I stand by shielding the guitar as atleast a good start, it wont cure the Fizz of your Boss, that's just the Boss (A gate rather than supressor might work better) but i'd say fighting the source of the noise, the pickups, which are going to pick up all the noise and then have pedals and an amplifier amplify it is your best bet to cut down on noise, Positions 1, 3 & 5 of my single coiled strat are dead quiet, quieter than my Humbuckers perhaps (I also have a metal scratchplate which probably helps) i've recored very happily with that guitar without noise hassle.
Title: Re: DIY Noise Suppressors
Post by: Gordo on November 16, 2010, 03:14:16 PM
Quote from: Scruffie on November 15, 2010, 06:03:15 PM
I stand by shielding the guitar as atleast a good start,
I was always amazed to find out that the echoey flanged sound behind the solo in Heart's "Barracuda" was guitarist Roger Fisher holding the guitar cable he'd unplugged from his strat and waving it around behind his amp head while running a Ross Flanger.  I guess as far as noise goes sometimes bad=good...

That said, yeah, I agree.  If you can stop it at the source you have a good chunk of the problem solved.
Title: Re: DIY Noise Suppressors
Post by: Ben N on November 17, 2010, 08:21:38 AM
Absolutely true--about eliminating noise at the source. A set of Bill Lawrence pups isn't much more than an NS-2, and the tonal compromise involved (and there is one, to be sure) is, to my ears, prefereable to what noise gates and suppressors do. In DIY pedal-land, that means using MF resistors, trying out different semiconductors for lowest noise, being extra careful about layout and shielding, finding the best power solution, lowering input impedance where higher is not required, etc.
Having said all that, there may still be a place for noise suppression in some rigs, under some conditions, and as Mark pointed out above, the more subtly it can be applied and the more targeted it is to actual sources of noise the better. But the approaches are complimentary, not exclusive, and lowering noise at the source will permit suppression technologies to work more effectively and less obviously.
Title: Re: DIY Noise Suppressors
Post by: Steve Mavronis on November 17, 2010, 08:48:56 AM
Maybe I just need a pedalboard power supply filter too. Right now I don't even have a pedalboard and just place my "two" pedals on top of my practice amp!
Title: Re: DIY Noise Suppressors
Post by: petemoore on November 17, 2010, 09:43:54 AM
  I'd say maybe as a good approach in general:
  Figure out what you need it on.
  Say it's a hard compressing distorter, gate controlling the output by what the input is doing may allow better control to allow small voltage [low volume long note sustain] input to keep the gate open, cutting output only when input is very low [yet still enough higher than whatever noise the detector could be confused by..ie lower noise = easier to tell very low signals from noise].
  Otherwise, with the detector and the gate placed somewhere/anywhere in the chain, often a long one with various boosts of noise and signal, not necessarily in proportions that the detector will recognize in a way that coincides with what a noise supressor was thought to be able to do.