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

[Gurner]

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...

It should work, but actual results are going to be very dependent on that final FET - and as we all know, even if you had the right FET, that results can vary between FETs of the same type. The bit I'm not 100% about is why he's put a high resistor in the FET source path...I've had best results when using FETs as switches or voltage controlled resistors with the source firmly tied to a known potential....that resistor flies in the face of that.

Careful though it's not a MOSFET it's a standard FET, if you look at the datasheet for the gate threshold voltage http://www.fairchildsemi.com/ds/2N/2N7000.pdf , you'll see it's typically  2.1V (this is the point where the FET essentially stops being a path to ground for the signal - in other words off).....for that implementation I reckon you want a FET with a low a threshold as possible., else there's a risk that when the FET is on, it may take too long to turn it off once a signal comes though again (which could mean you'd lose a bit of the attack portion of your signal)

If you want to establish the final 'effect' this circuit has on the guitar signal, just disconnect the fet gate from the circuit & instead connect it to a pot wiper with say 0V on one outer lug & maybe 5V on the other outer lug....by turning the pot between 0 & 5V, you'll get a flavour/vibe how this gate acts (eg how it sounds when cutting in, what voltage is needed on the gate for your FET to turn the signal back on, etc)

[deadastronaut]

ahhh i thought it was a mosfet going by the weird symbol.......ive never used a mosfet!..only n-jfets... i found those 2n7000's in my drawer...

so could a jfet be used..j201' , mpf102 etc?...or could the 2n7000 be adjusted via resistor/pot to cut off at the right point?...hmmmm...dumb questions, but you know the score!...


edit: answered:     cheers G  i'll give it a go today, and see how it goes...

[Gurner]

ahhh i thought it was a mosfet going by the weird symbol.......ive never used a mosfet!..only n-jfets... i found those 2n7000's in my drawer...

so could a jfet be used..j201' , mpf102 etc?...or could the 2n7000 be adjusted via resistor/pot to cut off at the right point?...hmmmm...dumb questions, but you know the score!...

A mosfet works opposite to a jfet - a jfet normally conducts until a voltage is applied to turn it off, whereas a MOSFET doesn't normally conduct until you apply a gate voltage to turn it on. An n channel jfet would need the gate to go negative wrt the source to cut it off...therefore I don't think you should be using an n-channel. In my (all too quick) opinion, you should try a a P channel jfet

[deadastronaut]

arghhhhhhh....i'm sure i  haven't got any p fets..!!!... .......boo hoo....


hmmmmm....maybe i should bread and 'tweak' the dod/mxr gate instead.....but the demo's ive seen  on them are really slow to kick/gate in, thats what put me off those..
the tried n tested (and failed imo) ones!..

[askwho69]

@Rob - the led is for gate indicator.. i try the first schem at the french site ... they said its working but for me it isnt working i wonder how i wonder why? hehehe
dont try the MXR it didnt work for me either try the DOD i think this is working but the Led/ldr is the issue you need to use vactrol ithink for fast clamp or the specific CLM50

[deadastronaut]

@ask: cheers, yeah i have that schemo too...i was looking at that one..

...i'll give this one a go, and try with led/ldr for now , and if it seems promising i'll grab a vactrol or 2....


i think the french were having a laugh...oooh  la la....


edit:  just one pot?....no threshold/ release?....hmmmm....

[askwho69]

its threshold : D give it  a try rob the french has togo gate too but never tried it

[Fender3D]

...
i think the french were having a laugh...oooh  la la....


edit:  just one pot?....no threshold/ release?....hmmmm....

Dicking with 220K collector's resistor (ala dynacomp) will give you different release....

BTW
just "trim" your "R" for a french taste... 

[deadastronaut]

bonjour!...ooohh la la.....tre bien!....bluu bluu bluu....(sound of an accordion)...

so 220k will add release..

i'll give it a go later...on a mission to find a @#$%ing cd today for a xmas prezzie for the missus...


edit:  
http://www.ebay.co.uk/itm/CLM50-50-/320432976290?pt=LH_DefaultDomain_0&hash=item4a9b4b31a2

WTF?......

whats a good equivalent thats not pricey as @#$%?...

[scuzzphut]

Resurrecting the thread - I've just built this from the vero here -------->  http://www.aronnelson.com/gallery/main.php?g2_view=keyalbum.KeywordAlbum&g2_keyword=vero&g2_itemId=45758

, but no joy.

Got all the right parts, used films for the big caps and a BS170/TLO71/2N3906.

The LED seems to respond to varying the threshold pot - but I always have an output signal (which doesn't even seem to vary in volume)

Anyone get any further ?

[deadastronaut]

nope!...i gave up on it...sorry...

[askwho69]

Hello it gated but no gain at all better not doing it rather than wasting time

:rob thanks rob you Know what i mean

[scuzzphut]

Thanks guys - for the record - I didn't get much further myself. Oh well.........

[Earthscum]

I've been watching this since it popped up, and forgot about it. Y'all do realize the envelope detector in the "french dude" schem is essentially a full sensitivity Nurse Quacky EF? Or, probably more akin to the DQ, but if you can get the NQ working, you should be able to get this going. I'll give it a go. I don't really see why it shouldn't work except there's no voltage bias to the top of the mosfet, and I don't think they work as VCR's the same way jfets do. It makes sense to me to lose the 22uF cap (C4) and move it to the output. This will give the mosfet drain a 4.5V bias, giving the source a voltage, and therefore giving the gate something to reference against.