Muffler Noise Gate

Chuck D. Bones

Well-known member
Q1 is installed now, correct? Do you get any noise gating at all? Does rotating the GATE control make any difference? The gain should be unity for large signals and there should be a significant gain drop when the gate kills the signal. A couple of things we can try:
1) Measure Vp on Q3. With Q3 removed from the board, connect the +lead of your DMM to Q3-2. Connect the - lead to Q3-3 and to the negative side of a 9V power supply or battery. Apply +9V to Q1-1. Whatever voltage reads on the meter, that is Vp. Should be between 0.5V and 4.0V.
2) Verify that the circuit is driving Q3 correctly. With Q3 installed, measure Q3-3 with no signal. Should be at least 5V.
 

Mourguitars

Active member
can i use a battery clip and battery for Q3-3...going to try that now

I get nothing when rotating the pot CDB..i checked that this morning when looking at the resistors
 

PKRPedals

Active member
So exactly how is the muffler supposed to work? I built mine and it seems kind of backward to me. It opens up completely at around 12 o’clock. It clamps off totally around 7ish. Is that the way it’s supposed to work?
 

Chuck D. Bones

Well-known member
I have not used one, but I can tell you this...
Turning GATE clockwise makes the signal detection more sensitive. The detector has a huge amount of gain, so I expect that when GATE is turned up high enough, even the tiniest bit of hum or noise will open the gate. There are a couple of resistors you can change if you want to alter the GATE adjustment range.
 

PKRPedals

Active member
The only gate I ever used was the one on the 5150 overdrive. It started open and clamped more when turned clockwise but never shut off completely. The gate just closed faster.
 

Mourguitars

Active member
Q1 is installed now, correct? ......(yes )..... Do you get any noise gating at all? ( no )..... Does rotating the GATE control make any difference? ....(no ).... The gain should be unity for large signals and there should be a significant gain drop when the gate kills the signal. A couple of things we can try:
1) Measure Vp on Q3.....( 8.33v ) With Q3 removed from the board, connect the +lead of your DMM to Q3-2. Connect the - lead to Q3-3 and to the negative side of a 9V power supply or battery. Apply +9V to Q1-1. Whatever voltage reads on the meter, that is Vp. .....( 4.70v..then it goes down due to shaky hands .56v )..... Should be between 0.5V and 4.0V.
2) Verify that the circuit is driving Q3 correctly. With Q3 installed, measure Q3-3 with no signal. Should be at least 5V.....(8.31v ) .....


CDB it was easier to put the readings in these (....)
 

Mourguitars

Active member
When turning on the Hush on my effects , i still have some hiss.....Turn on the Muffler around 8-9 pm it stops, open it up all the way and i get noise again....seems like that 8-9 pm is the spot, so its doing something.

Have The QoB2 on distortion both sides ON..its quite noisy being 2 Blues Breakers on the settings in the pic, i Put the Gain on the JMP-1 on 20 ( max) so its doing something...

Maybe its all that it can do, but it is altering the sound now...

Mike
 

PKRPedals

Active member
Mike
That's about right with mine. Mine works pretty good between around 7 to 10 I think. If you put it in the loop, it acts completely different. When I put mine in the loop, I don't get any sound until it gets to 12 and after. It works but it's not the ideal gate.
 

Mourguitars

Active member
Mike
That's about right with mine. Mine works pretty good between around 7 to 10 I think. If you put it in the loop, it acts completely different. When I put mine in the loop, I don't get any sound until it gets to 12 and after. It works but it's not the ideal gate.

Gotcha...i haven't tried with a head yet in the loop , i knew it wasn't going to be like a Muzzle !

At least its doing something , CDB really went out of his way to help me figure it out, i learned a lot from him and

...Many thanks to him !(y)

Mike
 

Chuck D. Bones

Well-known member
I enjoy helping. I learn stuff here too. I like troubleshooting. All I ask is that you meet me half-way. Try to do a good job soldering and cleaning your board. Take pictures that have enough detail that we can read the resistors and tell which way the ICs are facing. If you do sloppy work, it leaves me with the impression you don't give a shit. I know that not everyone is going to develop the level of skill or dedication to build stuff like the master builders here (you know who I'm talking about), but it's a worthy goal and everyone should give it their best effort.

I used to work at a large aerospace firm. The design and build quality there was top shelf all the way. Had to be. We put stuff in space and it had to work for 10 years or more. I recall sending a piece of test gear that a new guy had built to Helen, our inspector, for buy-off. The build quality was pretty bad and I should have known better than to show it to her. She was truly offended that anyone would have the gall put something like that on her workbench. Everybody in the manufacturing area heard Helen tell me in no uncertain terms to "Git that bullshit outta here!"
 
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