The best noise gate?

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alexc said:
Good luck with it - gating is a fine enterprise. I couldn't get by without my ones scattered throughout the place.
It's funny. Although I have been instrumental in promoting the concept of selective noise-gate in my country, I almost never use them today, in fact since I switched from dedicated recorder to recording in a PC.
I do that in the DAW, and even then, I don't use the noise-gate plug-ins. I use the De-noiser a lot, that works by grabbing an imprint of noise and applying an inverse filter, and pure and simple editing for cleaning lip noise, breath and whatever unwanted random noise. I don't even use the de-breath plug-in.
 
Well I’ve made 3 pcbs now and I have all the bits lying around to populate them, I’ve made a Psu as well.
I know these won’t be the best but should help for the moment at least!
Will keep my eyes peeled for either the BSS, Dbx 1074 or Ds101s.
It’s good to learn about how these are constructed.
 
abbey road d enfer said:
It's funny. Although I have been instrumental in promoting the concept of selective noise-gate in my country, I almost never use them today, in fact since I switched from dedicated recorder to recording in a PC.
I do that in the DAW, and even then, I don't use the noise-gate plug-ins. I use the De-noiser a lot, that works by grabbing an imprint of noise and applying an inverse filter, and pure and simple editing for cleaning lip noise, breath and whatever unwanted random noise. I don't even use the de-breath plug-in.

I can understand that for sure ...  as my experience in diy has grown and my build 'noise' has decreased, I really do see the 'noise gate' riding into the sunset  ..  mostly.

But that's a relatively recent thing in my world. My face would light up always when I could tame an otherwise great 'sound' but with noise  ...  pickups, cables, excess gain  ....    all that kind of thing.

The more modern 'freq selective' and 'multiband'  are awesome! You really can 'gate' the bottom end and leave a lot of the rest fairly un-damaged.  I've mostly done that in digital, but perhaps '2 gates with a crossover'  kind of thing is doable in todays diy environment.

I find some of the modern implementations interesting ..  afaik  ..  the 500 series ones  ... I think there are some 'discrete' types out there  ...  like some of the german names with the gain cell with about 20 finely matched and calibrated little transistors ..

Fav. sw gate is in 'team DNR Mix Control' plug  .. it really works well  ..  I'd like to see a multiband version of  that in some analog hardware.
 
And how about some the digital hardware 'creative' gates  ..  there was an older one Alesis    and a recent one  from  Klark-Tecknik I think it is  .. (Behringer nowadays)

Both had  a focus on 'transient shaping' gates  .. the Alesis with about 12 knobs each of 2 channels    ....  and the KT, about half as many knobs per channel but  with 4x  in a 2ru.  I'd love to try that one out. No idea if it is great to use or so.

And that old standout from  Presonus .. 8chan dynamics incl gate  - they were not bad as I recall.
 
I had a presonus and they were very clicky on the gate, the compression wasn’t all that either.
I may end up not using them and just using everything post like I have been but mainly as I’ve said I want to try them on drums for live tracking of band in one room.
 
All pcbs populated apart from 0.47uf tants, red and green leds and 2.2meg pots.
When looking at the schematic I’m not sure whether there are two 8.2k or 82k resistors?
Pretty sure it is 8.2k but wanted to check?
 
Here's the case and the side ways mounted pcbs, will fix everything with L brackets, need to make one more channel to finish it off.
Need a few more parts to complete the final channel.
Will finish and test this next week, i know its not going to be as great a unit as the drawmers or even the Behringers but i've enjoyed putting it together, just cant justify the dosh on anything else at the moment.
 

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Spencerleehorton said:
All pcbs populated apart from 0.47uf tants, red and green leds and 2.2meg pots.
When looking at the schematic I’m not sure whether there are two 8.2k or 82k resistors?
Pretty sure it is 8.2k but wanted to check?
The one in the collector of the North transistor is 8.2k.
The one that goes above  the South-West transistor is 82k.
 
Thank you I’ll update schematic and share so it’s clear, still waiting on a few more bits, so no more progress.
And I can’t seem to post anymore pictures as it says download folder is full?
 
ok couple more things to check as this schematic is not quite clear to me.

orientation of the drain gate and source on each FET i want to check just in case i've got this wrong.
i know where the gate is obviously but which is the drain connected to, is it on the first FET connected to the 6.8k/1.5k/ ATN ?
and source to the 4.7uf/1.5k?

on the second FET source down to GND?
 
Spencerleehorton said:
ok couple more things to check as this schematic is not quite clear to me.

orientation of the drain gate and source on each FET i want to check just in case i've got this wrong.
i know where the gate is obviously but which is the drain connected to, is it on the first FET connected to the 6.8k/1.5k/ ATN ?
and source to the 4.7uf/1.5k?

on the second FET source down to GND?
That's correct. In fact FET's are symmetrical and keep working (almost) normally reversing source and drain.
 
Spencerleehorton said:
pretty sure i have it correct and have signal through but don't get out what i put in?
gate seems to work but very low signal at output?
Do you mean that you notice the signal switching in/out but being very low?
That may point to two things:
FET doesn't conduct properly.  Turn the Range pot at its minimum (shorting source and drain), there should be normal output.
If this does not work, I suspect the output amp. You need to check its proper operation; measure the DC voltages at the junction of output Q's collector-560r-15k and at the other side of same 15k res.
 
right i got 15.2v on collector of last transistor which is connected to 560R and 15k and goes to the 47uf cap.
8.82v before the 15k resistor.

Ive put the circuit into LTspice and done a crash course in it and im getting very similar voltages at these points.

I mean the output signal is very low compared to the input signal with the gate in the off position, if that makes sense?

Ive used 6.8uf caps in the first stage rather than 4.7uf, but dont think would make any difference.

Also used BC560 for PNP and BC550 for the NPN, ATN pot is 50k, everything else is the same.
 
ok, confusion here, what i'm saying is when gate is fully open (In bypass) there is hardy any signal on output, on my scope i have to set to very zoomed in to see any signal compared to signal on input.

Im taking it that the red light is when the gate is closed and the green led is when the signal passes through.

Do you understand me?

btw power wise on my adjustable PSU at 24v it only reads 0.03mA power consumption.
 
Spencerleehorton said:
ok, confusion here, what i'm saying is when gate is fully open (In bypass) there is hardy any signal on output, on my scope i have to set to very zoomed in to see any signal compared to signal on input.

Im taking it that the red light is when the gate is closed and the green led is when the signal passes through.

Do you understand me?
OK; you should have answered my previous questions about signal in forced bypass.
Now, since you have a 'scope, check various points, but first let's number teh transistors on the schemo, 1 to 5 North and 6 to 12 South., numbered from West to East.
AC voltage at input
AC voltage at drain & source of Q6
AC and DC voltages at Q7 base
AC and DC voltages at Q9 collector
DC voltage Q5 collector

btw power wise on my adjustable PSU at 24v it only reads 0.03mA power consumption.
It's totally abnormal; are you sure it's not  0.03A (30 mA). That would be about right.
 
right here is my findings:

1. input voltage = 0.807v AC
2. Q6 drain = 0.011v AC
3. Q6 source = 0.008v AC
4. Q7 base = 0.008v AC
5. Q7 base = 8.07v DC
6. Q9 collector = varies AC
7. Q9 collector = 15.22v DC
8. Q5 collector = 72.4mv and when i change Sensitivity pot on input it goes up to 5.05v AC
 
Spencerleehorton said:
right here is my findings:

1. input voltage = 0.807v AC
2. Q6 drain = 0.011v AC
3. Q6 source = 0.008v AC
4. Q7 base = 0.008v AC
5. Q7 base = 8.07v DC
6. Q9 collector = varies AC
7. Q9 collector = 15.22v DC
8. Q5 collector = 72.4mv and when i change Sensitivity pot on input it goes up to 5.05v AC
There's something very wrong from the start.
The signal (AC) at the drain of Q6 should be between 70 and 140mV depending if the gate is open or closed.
I would suspect a resistor value, or the FET shorted or cross-wired.
 

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