# Muffler Noise Gate



## Mourguitars (Oct 7, 2019)

I socketed my Q1-Q3 and picked the pedal up and heard a rattle and one fell out , so i wanted to test to see if they were reading right since they were loose in the sockets, got weird readings , sent this to CDB had me try a few things and wanted me to move it here...
here's what i sent CDB



https://imgur.com/84Wdtz6


his reply to check......

Going left to right...
Q1-E This reading makes no sense. Should be 0.6V lower than Q1-B
Q1-B Correct
Q1-C Correct
Q2-E Correct
Q2-B Correct, your meter is loading it down a little.
Q2-C Correct
Q3-D Wrong, should be near 5V, maybe a little lower from meter loading.
Q3-S Wrong, should be 5V (Vref_B)
Q3-G Correct, same voltage as Q2-C

I can't tell you why they are wrong. Dirty board? ( no triple checked )  Short somewhere?  (looked every where , none that i see) Verify R3 is 22K. (did ) You can measure it in-circuit, just power off and pull Q1 out of the socket. reading below

R3 is reading 21.7  

triple checked board for any flux or shorts....

Mike


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## Mourguitars (Oct 7, 2019)

Was telling CDB that i have a appt to get Glasses on the 15th, wished it was sooner, i put a 2n5458 instead of 2n5485 rechecking everything..


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## Chuck D. Bones (Oct 8, 2019)

We still have to solve the incorrect voltage on Q1's emitter.  Any chance that transistor is the wrong part no. also?  Try measuring the voltage at Q1-E socket with Q1 not installed.  Should be zero volts, unless there is a sneak path somewhere.


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## Mourguitars (Oct 8, 2019)

Chuck D. Bones said:


> We still have to solve the incorrect voltage on Q1's emitter.  Any chance that transistor is the wrong part no. also?  Try measuring the voltage at Q1-E socket with Q1 not installed.  Should be zero volts, unless there is a sneak path somewhere.



Ok,  got a half day of work today but will do that this afternoon, those are the right ones in Q1-Q2 . I trimmed them low profile after testing them on the meter  and retested , one fell out  and was rattling around that’s what caused me to inspect things.  I’ll post the reading’s as well....I put the correct Q3 2n5485 I my cart at Tayda....I googled a sub but all the ones I have won’t work...

Very good catch CDB ...when you said the readings were wrong on Q3 ,  rechecked , pulled it out and it was the wrong part #

Mike


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## Mourguitars (Oct 8, 2019)

Q1 and 2 are 2n3904 both read around 
hFE 288
vF 686mV on tester , Q2 is 288 and 688

Q1 reads with 2n3904 out these readings below tested 4 times and pedal on CDB

0.05
5.59
9.08


Mike


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## Mourguitars (Oct 12, 2019)

I received the 2n5485 yesterday , tested them... there all in the same ball park.. installed ...checked the readings that you said Q3 should read ill post them later...but still the pedal isn't clamping down on the noise like say a Hush or the EHX silencer..


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## Mourguitars (Oct 12, 2019)

https://imgur.com/a3SHYuV


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## Mourguitars (Oct 12, 2019)

Lightly flowed each solder joint...still have the same readings above

A500k reads 499k



https://imgur.com/unsAs9q


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## Nostradoomus (Oct 12, 2019)

The joint in the row above your led (100k resistor) looks fairly suspect!
The tagboardfx folks suggest that you match your 2n3904s hfe for best results.


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## Chuck D. Bones (Oct 12, 2019)

You reported two different readings for Q1. 
Tues 10/8:
E  0.05V
B  5.59V
C  9.08V

and on the notpad above:
E  7.20V
B  4.98V
C  9.09V
Is is possible that the 7.20 is 7.20mV?

Q1 should read (approx)
E  4.4V
B  5V
C  9V

The only way to get the reading you got on Tues is for Q1 to be blown (your meter says it's good) or for Q1's connection at the socket to be bad. Where exactly do you put the meter when measuring Q1's voltages?  Try measuring right on the leads.

Matching the 2N3904s is completely unnecessary in this circuit.  Any transistor that is in-spec should work.


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## Mourguitars (Oct 12, 2019)

Nostradoomus said:


> The joint in the row above your led (100k resistor) looks fairly suspect!
> The tagboardfx folks suggest that you match your 2n3904s hfe for best results.




Just a weird angle i see what you seen it was a peak of solder i didn't clip..i reflowed it anyway


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## Mourguitars (Oct 12, 2019)

Chuck D. Bones said:


> You reported two different readings for Q1.
> Tues 10/8:
> E  0.05V
> B  5.59V
> ...




I took it out of the enclosure this morning , before i was putting the ground inside the screw hole in the enclosure and making sure it made contact with my hand by pressing...this morning i tested the ground by putting it on the ground pad at the top of the board

Do you want me to remove the socket's for Q1 then retest with Q1 2n3904 on the PCB ?


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## Mourguitars (Oct 12, 2019)

Those readings on Tues was with the 2n3904 out..GDB

With the 2n3904 out of socket it reads :
0.15
5.59 
9.08


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## Mourguitars (Oct 12, 2019)

Found some 2n3904 i bought from Mouser vs Tayda

6.65
5.58
9.08

tested all 10 i bought #'s were pretty much the same out of this pack..plus or minus 1 either way


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## Mourguitars (Oct 12, 2019)

Carefully removed the socket on Q1 and tacked in the 2n3904 and still got the same reading

6.65
5.58
9.08

time to put this one in a box and come back at a later day !

Mike



https://imgur.com/DRy4jw1


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## Mourguitars (Oct 12, 2019)

This build called for a LM4558 but I subbed with a TL072...could that be the problem?

Ill recheck all the resistors , and make sure I didn’t put a different value one in the wrong spot , 6 hrs today staring at this thing, removed Q1 socket and like I said tacked it to the PCB....it’s has to be something simple I’ve overlooked 

Ill stay on it !


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## Nostradoomus (Oct 12, 2019)

4558 and tl072 are interchangeable


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## Mourguitars (Oct 12, 2019)

Nostradoomus said:


> 4558 and tl072 are interchangeable



ok ...that’s what I thought but didn’t know if the voltages were different...Q1 first pin is getting around 2v more than it should...been a real head scratcher for a simple build


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## Mourguitars (Oct 13, 2019)

Rechecked all resistors they are right...dunno


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## Chuck D. Bones (Oct 13, 2019)

Mourguitars said:


> Those readings on Tues was with the 2n3904 out..CDB
> 
> With the 2n3904 out of socket it reads :
> 0.15
> ...



OK, got it.  
E should be zero, the 150mV must be from leakage in C7, not a problem.
B should be 5.1V, but zeners have some tolerance so 5.59V is acceptable.

I wonder if Q1 or IC1.1 are oscillating.


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## Mourguitars (Oct 7, 2019)

I socketed my Q1-Q3 and picked the pedal up and heard a rattle and one fell out , so i wanted to test to see if they were reading right since they were loose in the sockets, got weird readings , sent this to CDB had me try a few things and wanted me to move it here...
here's what i sent CDB



https://imgur.com/84Wdtz6


his reply to check......

Going left to right...
Q1-E This reading makes no sense. Should be 0.6V lower than Q1-B
Q1-B Correct
Q1-C Correct
Q2-E Correct
Q2-B Correct, your meter is loading it down a little.
Q2-C Correct
Q3-D Wrong, should be near 5V, maybe a little lower from meter loading.
Q3-S Wrong, should be 5V (Vref_B)
Q3-G Correct, same voltage as Q2-C

I can't tell you why they are wrong. Dirty board? ( no triple checked )  Short somewhere?  (looked every where , none that i see) Verify R3 is 22K. (did ) You can measure it in-circuit, just power off and pull Q1 out of the socket. reading below

R3 is reading 21.7  

triple checked board for any flux or shorts....

Mike


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## Chuck D. Bones (Oct 13, 2019)

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.


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## Mourguitars (Oct 13, 2019)

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


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## Chuck D. Bones (Oct 13, 2019)

Battery is ok.


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## PKRPedals (Oct 13, 2019)

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?


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## Chuck D. Bones (Oct 13, 2019)

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.


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## PKRPedals (Oct 13, 2019)

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.


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## Mourguitars (Oct 13, 2019)

Chuck D. Bones said:


> 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 ) .....
> 
> ...


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## Mourguitars (Oct 13, 2019)

going to put it back in its enclosure to test it now ....have a lot of ground hum out of the box


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## Mourguitars (Oct 13, 2019)

Around 8 pm it sounds like its wanting to clamp down, if you open it up all the way i hear a little more high end on the guitar...its doing something but nothing like the EHX Silencer



https://imgur.com/pIqyM10


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## Mourguitars (Oct 13, 2019)

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


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## PKRPedals (Oct 13, 2019)

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.


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## Mourguitars (Oct 13, 2019)

PKRPedals said:


> 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 !

Mike


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## PKRPedals (Oct 13, 2019)

Yeah he’s very helpful. It’s nice to have somebody that doesn’t seem to mind helping.


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## Chuck D. Bones (Oct 16, 2019)

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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## Robusto (Jan 22, 2020)

Mourguitars said:


> This build called for a LM4558 but I subbed with a TL072...could that be the problem?



How about the RC4558P? Is that acceptable?


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## Nostradoomus (Jan 22, 2020)

It’ll be fine. Should be the same chip...first letters are just manufacturer codes. RC is Texas Instruments I believe, LM is lots of different companies.


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## Chuck D. Bones (Jan 22, 2020)

Any 8-pin dual opamp should work.  TL072 is my go-to opamp, it has worked well everywhere I've used it.  Note: I have not built a Muffler.


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## Chuck D. Bones (Jan 22, 2020)

Nostradoomus said:


> It’ll be fine. Should be the same chip...first letters are just manufacturer codes. RC is Texas Instruments I believe, LM is lots of different companies.


Dammit!  you beat me again!


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## Nostradoomus (Jan 22, 2020)




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## Robusto (Jan 23, 2020)

Nostradoomus said:


> It’ll be fine. Should be the same chip...first letters are just manufacturer codes. RC is Texas Instruments I believe, LM is lots of different companies.



Thanks for that. Always wondered what the differences were, although as long as it had 4558 somewhere in the middle of the alphabet soup, I ignored the rest and assumed it would work.

So, I finished building the Muffler last night and it does not work. It's passing SOME signal through the effect, just kind of makes fart noises, and the pot doesn't seem to have any effect on said farts. I haven't done any troubleshooting yet. I'll get to it this weekend and report back as needed.

I was using the famed Behringer "Josh says buy or die." Super Fuzz to test it, but that pedal doesn't make quite as much noise as I thought it would. I need to figure out something noisier. Maybe I should just record five minutes of white noise, put it on an iPod, and use that.


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## Mourguitars (Oct 7, 2019)

I socketed my Q1-Q3 and picked the pedal up and heard a rattle and one fell out , so i wanted to test to see if they were reading right since they were loose in the sockets, got weird readings , sent this to CDB had me try a few things and wanted me to move it here...
here's what i sent CDB



https://imgur.com/84Wdtz6


his reply to check......

Going left to right...
Q1-E This reading makes no sense. Should be 0.6V lower than Q1-B
Q1-B Correct
Q1-C Correct
Q2-E Correct
Q2-B Correct, your meter is loading it down a little.
Q2-C Correct
Q3-D Wrong, should be near 5V, maybe a little lower from meter loading.
Q3-S Wrong, should be 5V (Vref_B)
Q3-G Correct, same voltage as Q2-C

I can't tell you why they are wrong. Dirty board? ( no triple checked )  Short somewhere?  (looked every where , none that i see) Verify R3 is 22K. (did ) You can measure it in-circuit, just power off and pull Q1 out of the socket. reading below

R3 is reading 21.7  

triple checked board for any flux or shorts....

Mike


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## chongmagic (Jan 23, 2020)

Chuck D. Bones said:


> 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!"



Well I am glad you are here to help with troubleshooting, you are at truly an asset to the forum. And I learn a lot from you!


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## Chuck D. Bones (Jan 23, 2020)

Thanks for the kind words.  I've learned a lot here myself.


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## Robusto (Jan 25, 2020)

Robusto said:


> I haven't done any troubleshooting yet. I'll get to it this weekend and report back as needed.



Yep. I had a 22k resistor where a 1M should have been. All fixed and working now.


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