mxr noise gate help needed

[makkimo]

hi!!!
trying to build a mxr noise gate from tonepad (callate gate 2)
readed all posted about it but can't find the fix so here i'am again!!!  :oops:
first i'm using a 2n5485 FET listed as a suitable alternative for the 2n5952 one but finding a little difficult to orient it correctly, anyway i think the right is the same as in the layout with the flat face to right....maybe...
then used two 2n3904 oriented in the same way as in layout
a 5.1v diode and a tl072 as the op-amp

well i'm not sure about  how a noise gate works, never used one...
i've engaged mine and nothing the signal comes out clear but seems not to reduce noise
what's the right function of the sensitivity pot?
the only thing my noise gate does is that when i turn the sensitivity pot the signal becomes more and more distorted
going to read voltages hope you can help me:
using a battery not so charged (only 8.25v)
after the zener - 4,20v
Q1:
E 3,20
B 2,65
C 8,22

Q2:
E 0,00
B - 2,26 ?? negative ?
C 0,05

tl072: FROM PIN 1 TO 8
4,21
3,81
2,90
0,00
8,20
4,07
4,07
2,72


THANKs

[dosmun]

A noise gate will do nothing when you are playing through it normally.  What it does it shut of your signal (gate it) when  you are not playing or are playing very lightly.  This depends on the sensitivity setting.  The higher the setting the sooner it shuts down your signal.   Basically it is designed to shut off your signal when you are not playing to eliminate noise and hiss.

This is probably not a great explanation.  I am sure someone else can explain it better.

[makkimo]

hi after a long night of bad dreams about my new beautiful pedalboard with a black hole in the middle(the place for the dead mxr noise gate.... :evil:   ) i've rechecked the voltages and ...the tracks with negative voltage were gone ....well the pedal doesn't work yet it's got a critical drop in volume when engaged and the signal comes distorted (at only one position of the sensitivity pot the distortion seems to decrease but the volume keep oscillate while playing , i think this is not the right beaviour
the new voltages on the Q2 2n3904 are
E 0,00
B 0,37
C 3,32

on the fet i read:
G 2,56
S 4,25
D 4,25
PLEASE HELP ME!!!

[makkimo]

sigh sigh problem still unsolved ... :cry:  :cry:  :cry:
really no-one can say me somethig about that ?

[MartyMart]

PINOUT  ?
you must check with the transistors manufacturer, what the correct pinout is for that device, once that is correct, then you can "De-Bug" the circuit, otherwise you will go round in circles ( I've been there a few times !! )
Read the "De-Bugging/ what to do when it doesn't work" stickie also, which says post : schem/layout/parts subbed?/ pinout/ voltages   etc etc
I'm sure then someone here will be able to help out :-)

Cheers,
Marty.

[makkimo]

news:

i've added the attack pot it works only in one position i've now replaced the 47pf cap with a 39pf one......
replaced the 5.1v zener with a 6.1v one and the drop in volume is gone, now the sound attack is good and the sound comes out clear the bad is that the sensitivity pot is too sensitive so there is only one G-point where the gate seems not to distort the signal (in other positions the sound keep oscillate or distort) unfortunately this point doesn't fix all my problems..... :? the sound after a soft-right attack has a very fast intermittent and little distorted decay
really noone can help me with voltages or in suitable subs to fix that mess???!!!!
thanks

[tambek]

I'm having a similar problem:

http://diystompboxes.com/sboxforum/viewtopic.php?t=31080

but no solution yet...

[tambek]

Hi, I built the Callate Gate 1, and it works, i have no idea what was wrong with the second version...

[Yazoo]

What voltage should I expect from Vb?  I'm using the 5.1 Zener, as directed. I'm getting 3.63V from a 9.45V battery.

:?: