DIY noise gate will work but need modification.

Started by nguitar12, May 29, 2016, 09:23:43 AM

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nguitar12

Hi today I build a noise gate and it will work. However I need some info on modding the circuit to make it fully work for my need. Here is the schematic:



The first problem is the threshold of this circuit is too low. I can't even get a non-gated sound for my clean tone (unless boosted). How to make the overall threshold higher?

The second problem is it does not give a nature fade out the sound will get chopped suddenly. I trt to add a cap between the gate and the source of the BS170 but what it affect more seem to be the "hold" time rather then the decay.

Any idea on the modification? Thanks

nguitar12


dschwartz

Im no expert in noise gates..but with my intuition and understanding of the circuit i may say that:
Forvthe gate issue, transform the 1M pot into a voltage divider, so the signal can go to 0.

For the decay time, place a resistor (or pot) after D1, so you can change the RC charge time of the cap (it will also affect the attack time, though)

Read about envelope followers for more ideas
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nguitar12

I tried both your mod. For the threshold issue. I later on find that I need more signal to go into the base of T1 so basically I am not looking to get the signal going to 0 but a stronger signal. It seem that I have to increase the gain of T1 to get a lower threshold (just guessing. correct me if I am wrong)

For the decay mod. I tried it as well I place a 1M pot after D1 but once again it control the "hold" time instead of decay. The noise will remain at the same level for period (hold time) and than chop suddenly.

Kipper4

Try a bigger charging cap c5 I'd go with 470nf upto 10uf. For a longer decay.
You can always put a pot in parallel with c5 later on to adjust the decay try 1M for decay pot.
Just some stuff to try. It might work.
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poiureza

#5
Hello,

I'm interested in this as well.
Did you eventually manage to improve it ?

For the treshold issue, the Mosfet is getting too much juice at the gate.  So yes, increase the 1M pot ... or you could lower the gain of T1 or (better) of T2.  Adding a couple kOhms to the emitter leg could maybe work already.

I think you can only modify attack and decay (both are tied here) by making a larger RC time constant.

Kipper4

Ma throats as dry as an overcooked kipper.


Smoke me a Kipper. I'll be back for breakfast.

Grey Paper.
http://www.aronnelson.com/DIYFiles/up/

pinkjimiphoton

i built this on  vero a couple years ago and circle filed it cuz it was so crappy ;)

its hotamp's noisegate, aka hells gate from the french stompbox forum, technigitarre or however they spell it.

its  funny, i came across this one on another site, thought it looked familiar and posted it to my facebook a couple days ago.
rich chimed in with what he went thru with it and for now i'm abandoning it as a potential build
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Lithium_Grim

Quote from: Kipper4 on May 30, 2016, 06:06:28 AM
Try a bigger charging cap c5 I'd go with 470nf upto 10uf. For a longer decay.
You can always put a pot in parallel with c5 later on to adjust the decay try 1M for decay pot.
Just some stuff to try. It might work.

Shouldn't the pot go after D1 but before C5 so it forms a RC? Or am I missing the point why it should be in parallel with C5?

manuel.marsicobetre

hello everyone, does this project work?
Is there any schematic or layout with improvements that can help me build it?