hell's gate/noise gate...anyone built this?..

[Fender3D]

That schematic seems too much over-simplified...
An input buffer should decouple the switching stage from input impedance.
100nF to ground on output is definitely too much...
And, shouldn't diode be reversed for a n-channel?

[DavenPaget]

That schematic seems too much over-simplified...
An input buffer should decouple the switching stage from input impedance.
100nF to ground on output is definitely too much...
And, shouldn't diode be reversed for a n-channel?

2N3906 is a PNP .

[Fender3D]

2N3906 is a PNP .

I was talking about FET

[DavenPaget]

but it's going through the BJT ... the input before the fet goes into the base of the 2N3906 and switches forward .

[Fender3D]

but it's going through the BJT ... the input before the fet goes into the base of the 2N3906 and switches forward .

nope,
the 2 transistors (FET and BJT) are just "paralleled"

[DavenPaget]

I don't see any paralleling  , the input before the fet goes straight into the base and the 3906 conducts but *never* sends any signal .
it's used to switch the LED   

[Fender3D]

I don't see any paralleling  , the input before the fet goes straight into the base and the 3906 conducts but *never* sends any signal .
it's used to switch the LED   

Whatever gets out from the op amp, it goes to BJT AND to FET.
FET is a n-channel...

[DavenPaget]

I am aware . That's why LED negative goes towards emitter . Therefore , the LED is conducting towards ground and not the FET .

[Fender3D]

I am aware . That's why LED negative goes towards emitter . Therefore , the LED is conducting towards ground and not the FET .

I got it... 
When I talked about diode above, I was referring to the diode on op-amp's output...
lol

[deadastronaut]

right, i'm back from dinner.........so!.....will it/should it work or not?.....

(i had sausage and mash btw)..yum yum...

[DavenPaget]

Oh so it's the switching diode 

Naut , try flipping the 4148 over .

[deadastronaut]

nope!.

[DavenPaget]

nope!.

Or maybe the french guy just wanted it to cut volume 

[deadastronaut]

 ...

maybe he was just havng a laugh!.......must be some kind of french humour!!!!..........

[deadastronaut]

right, i think ive found the proper schemo!!!!!..by following the links in the pdf..and translating..

i'll bread this and see how it goes....i may be some time....talk amongst yourselves....

[deadastronaut]

and my interpretation:

[DavenPaget]

I didn't figure it out until now , but i think BS170 was used and was kind of better for his schem because the operatus morandi was to have the signal blended in with the BS170 and the opamp at the same time , then the FET do the gating . But i don't really know the effects of using a 2N7000 instead of the BS170 for this though .. might be wrong 

[Gurner]

so if I'm reading it right, IC1B is being used as a comparator, when the incoming signal goes above the voltage level set on pin 6 by VR3, the opamp will swing high the will cap charge up almost instantly & cuts the FET off (thereby allowing the signal out).

When the incoming signal stops, the cap discharges through the 470K pot (think of it as a delay before the gate kicks in after the signal has stopped), once the voltage on the fet gate falls sufficiently the fet is switched on and shunts the output signal to ground.

[askwho69]

I tried this before it didnt work for me either ... i think bs170 is a must  here, i tried the 7000 before no sound when its 170 i got Super Gated sound... avery weak sound

[deadastronaut]

morning!...round 2:...

@Gurner: hi man, good explanation,  so does the schemo above look like it should work then?...the guy had a layout and pcb too and builds on his site.so im guessing yes!...!!!!!!...

@Askwho:  did you try the scheme above...or that first schemo simple one with the led etc!!!!!?....i know that don't work!..

the 2n7000 is an alternative mosfet according to something i read...... ..whether it actually is or not is another thing...