# Monarch accidentally received 18v



## dlazzarini (Apr 11, 2021)

I just finished the Monarch. When I first started playing with it it seemed pretty normal but as time went by it started getting really farty no matter where the settings were. The harder you chug the fartier it gets. I then discovered that I had it plugged in to the 18v slot on my power supply. My caps are all more than adequate and I believe the 4580 and the j201’s can handle it. Is there anything else I. There that I may have damaged?


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## music6000 (Apr 11, 2021)

Try a different OpAmp, TL072, 4558 , It maybe a fake 4580!


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## dlazzarini (Apr 11, 2021)

I’ll try that tomorrow. Thanks for the advice


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## Chuck D. Bones (Apr 11, 2021)

18V won't hurt that circuit.  My best guess is a bad solder joint has reared it's ugly head.  Measure the voltages on Q2-D, Q4-D and IC1-7.  And do some visual inspection.  Stress points are where the switches and pots are soldered into the board.  Any misalignment can lead to cracks in the solder.  If you used sockets, check them for loose parts.


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## dlazzarini (Apr 11, 2021)

I was hoping you would pop in. I went back over every solder joint. Nothing unusual in the visual inspection. Q2-D=8.98v,  Q4-D=8.97v,  IC1-7=4.58v.  I will mention that these are new production j201’s from Mouser. I’ve also tried other op amps. Still pretty farty/sputtery most prominent on the lower register chugs. Very present with active Fishman Fluence’s. Much more subtle with passives.


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## Chuck D. Bones (Apr 11, 2021)

My bad, I meant to type Q1-D & Q3-D.  While you're at it, check Q1-S & Q3-S.  It's possible for JFETs to be in spec per the datasheet and not work in a particular circuit.

IC1 voltage is good.


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## dlazzarini (Apr 11, 2021)

Q1-D=4.65v,  Q3-D=4.57v,  
Q1-S=0.12v,  Q3-S=0.07v


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## music6000 (Apr 11, 2021)

Have you checked the Footswitch, I have experienced the farting out with dodgy contacts?


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## dlazzarini (Apr 11, 2021)

music6000 said:


> Have you checked the Footswitch, I have experienced the farting out with dodgy contacts?


I have not other than checking the solder joints and continuity checks.  I will give it the once over again. What exactly do you mean by “dodgy contacts” and what exactly do you check?


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## music6000 (Apr 12, 2021)

Just Click the switch On & Off repeatedly to see if there is any change to the output of the pedal.
3PDT Footswitch is the Number 1 failure in pedals!


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## dlazzarini (Apr 12, 2021)

Will try it out tomorrow. This is my first pedal using j201’s. Don’t these normally have a bias adjustment? Could it be possible that one or more of the jfet’s aren’t being biased correctly by one of the fixed resistor’s?


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## music6000 (Apr 12, 2021)

dlazzarini said:


> Will try it out tomorrow. This is my first pedal using j201’s. Don’t these normally have a bias adjustment? Could it be possible that one or more of the jfet’s aren’t being biased correctly by one of the fixed resistor’s?


The only issue is your Pedal was working Good & then started going Bad, so no biasing would help you with that!


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## dlazzarini (Apr 12, 2021)

Problem is that I’m not 100% positive that that it was playing fine in the beginning. I’m wondering if I may have not noticed it right away. It’s only while I’m playing in the low registers on the E string, but it’s kind of subtle until you change your pick attack. Really gets farty with hard picking to the point it sounds like it’s right on the edge of cutting out. I also used it first with passive pickups. It’s a lot worse with the fluence’s


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## music6000 (Apr 12, 2021)

Are these the Interfet J201's that you purchased?
With this Muamp type of circuit, you don't need to bias like other Jfet circuits with Trimmers.
Can you show a good photo of your PCB & Components for a second set of eyes.


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## dlazzarini (Apr 12, 2021)

music6000 said:


> Are these the Interfet J201's that you purchased?
> With this Muamp type of circuit, you don't need to bias like other Jfet circuits with Trimmers.
> Can you show a good photo of your PCB & Components for a second set of eyes.


They are Interfet from Mouser.  All I have currently on my phone is the component side of the board. I’ll post it again.  I’m pretty proficient at soldering but I did reflow.  I do have a dust cap on the pot under the board. The pedal behaves the same outside of the enclosure as well.


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## music6000 (Apr 12, 2021)

I checked all your Resistors & Caps that i can read, All looks Good!
Check for Continuity on you toggle switches that Middle & Bottom pads only connect when toggles are UP.
Middle & Top pads only connect when Toggles are Down.
Could be those crazy pin *Interfet*s!


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## music6000 (Apr 12, 2021)




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## dlazzarini (Apr 12, 2021)

music6000 said:


> I checked all your Resistors & Caps that i can read, All looks Good!
> Check for Continuity on you toggle switches that Middle & Bottom pads only connect when toggles are UP.
> Middle & Top pads only connect when Toggles are Down.
> Could be those crazy pin *Interfet*s!


Thank you for taking the time to look it over. I’ll check them toggles after work. I’m starting to question those interfets myself. I knew the gremlins would catch up to me sooner or later. I’m about 30 builds into this hobby without one hiccup. Now back to back to back pedals. I’ve got the Emu Amp Sim sitting on the bench as well


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## dlazzarini (Apr 17, 2021)

*Hey there Chuck and Music6000. I swapped out all 5 of my Jfet’s.  It got rid of MOST but not all of the farty sound when picking hard but something’s still not right. I’ve heard this pedal and mine’s missing a whole lot of distortion. Here’s all of my voltages. Maybe you guys can help steer me in the right direction. I’ve checked and reflowed all joints, switches etc. 
Q1-D=4.61,  S=0.48,  G=0
Q2-D=8.96,  S=4.61,  G=4.27
Q3-D=4.64,  S=0.19,  G=0
Q4-D=8.96,  S=4.64,  G=4.24
Q5-D=6.21,  S=0.22,  G=0
IC pins
1=8.43
2=8.42
3=0
4=0
5=4.31
6=4.57
7=7.73
8=8.96*


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## Chuck D. Bones (Apr 17, 2021)

dlazzarini said:


> *Hey there Chuck and Music6000. I swapped out all 5 of my Jfet’s.  It got rid of MOST but not all of the farty sound when picking hard but something’s still not right. I’ve heard this pedal and mine’s missing a whole lot of distortion. Here’s all of my voltages. Maybe you guys can help steer me in the right direction. I’ve checked and reflowed all joints, switches etc.
> Q1-D=4.61,  S=0.48,  G=0  OK
> Q2-D=8.96,  S=4.61,  G=4.27  OK
> Q3-D=4.64,  S=0.19,  G=0  OK
> ...



Something is wrong with IC1.  Possible causes:
Bent lead, solder short, leaky C19, bad IC.

One other possibility: design error.  the JRC 4580 datasheet does not say what happens when either input is connected to the negative rail (ground).  Some opamps go haywire if you do that.  I'd think Brian Wampler would know better if that was a problem, but, it doesn't hurt to check.  Bend pin 3 up, temp jumper it to Vref and check IC1-7.  If IC1-7 is near Vref (4.5V) then that was the problem.


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## dlazzarini (Apr 17, 2021)

Chuck D. Bones said:


> Something is wrong with IC1.  Possible causes:
> Bent lead, solder short, leaky C19, bad IC.


Ok thanks for the analysis. I will start my search there and see what I can find. Thank you again


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## Chuck D. Bones (Apr 17, 2021)

music6000 said:


> Could be those crazy pin *Interfet*s!


Not this time.


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## dlazzarini (Apr 17, 2021)

Chuck D. Bones said:


> Not this time.


Ok Chuck. I found the negative leg of c19 was pulled out a bit. I removed and replaced. There’s still something not right. The only way I can make it sound remotely like a distortion is with all 4 pots maxed and the boost engaged. Without the boost engaged it sounds like a weak overdrive.  Changing c19 did change pin7 of IC1. All voltages on jfet’s were unaffected
IC1
1=8.42
2=8.42
3=0 
4=0
5=4.26
6=4.60
7=4.57
8=8.96


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## Chuck D. Bones (Apr 17, 2021)

Time to bust out the audio probe.  We'll try a binary search.  Listen to Q5-G.  That's right in the middle of the signal chain.  

If you get good distortion there, then we know everything in the first half of the circuit is good. 
If distortion is good, listen to IC1-5.
If distortion is bad, listen to pin 3 on the GAIN pot.

Based on what you find, we'll proceed from there.


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## dlazzarini (Apr 17, 2021)

Chuck D. Bones said:


> Time to bust out the audio probe.  We'll try a binary search.  Listen to Q5-G.  That's right in the middle of the signal chain.
> 
> If you get good distortion there, then we know everything in the first half of the circuit is good.
> If distortion is good, listen to IC1-5.
> ...


Got it.  That will be my next move then.  Thank you for your guidance


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## Chuck D. Bones (Apr 17, 2021)

We're gonna fix this, Man!


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## dlazzarini (Apr 17, 2021)

Chuck D. Bones said:


> We're gonna fix this, Man!


I have faith.


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## dlazzarini (Apr 17, 2021)

dlazzarini said:


> I have faith.


Here’s what I’ve got so far.  At Q5-G I have sound. It’s not distorted sound. With the boost on it’s close to unity gain with my input signal. With boost off its quite a bit lower in volume than input signal.  I then chose distortion is bad from your flow chart which took me to lug 3 of gain pot, where the signal is so small I have to struggle to hear it.  I did a little poking around while following the schematic and I’ve got good strong undistorted signal through C5 and into the left side terminals of C6 and R9. Big drop in volume on the right side terminals and into R10


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## Chuck D. Bones (Apr 17, 2021)

We're zeroing in on the problem.  Look for shorts or bad solder joints around C6, C7, R9, R10 and the GAIN pot.  With power off and GAIN set to zero, measure the resistance from GAIN pin 3 to ground.  Should be around 500K.  Measure each side of R9 to ground.  One side should be around 720K and the other side around 1.72M.


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## dlazzarini (Apr 18, 2021)

Good morning Chuck. Reflowed solder joints on C-6,7, R-9,10. Inspected all around the area under high magnification and I see no signs of shorting or broken traces. Resistance at Gain pot=519k, R9- 736K right side, 1.73M Left side


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## Chuck D. Bones (Apr 18, 2021)

That's all good.  I'm trying to understand why you lose so much signal going thru R9.

What is you audio probe feeding?  Should be something high impedance.  The higher the better.


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## music6000 (Apr 18, 2021)

Can you check for Continuity on the matching circles.


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## dlazzarini (Apr 18, 2021)

Chuck D. Bones said:


> That's all good.  I'm trying to understand why you lose so much signal going thru R9.
> 
> What is you audio probe feeding?  Should be something high impedance.  The higher the better.


I’m actually using an old pignose with the probe. I’m using a looper pedal for my signal


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## dlazzarini (Apr 18, 2021)

music6000 said:


> Can you check for Continuity on the matching circles.
> View attachment 11100


Will do as soon as I’m back at the bench. Thanks


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## Chuck D. Bones (Apr 18, 2021)

The resistance measurements you made effectively confirmed everything except the turquoise circles (Q3-G).

The Pignose is unsuitable for audio probing because its input impedance is so low.  If you want to continue using the Pignose, you need to insert a buffered bypass pedal between the audio probe and the Pignose so that the Pignose isn't loading the circuit under test.


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## dlazzarini (Apr 18, 2021)

Chuck D. Bones said:


> The resistance measurements you made effectively confirmed everything except the turquoise circles (Q3-G).
> 
> The Pignose is unsuitable for audio probing because its input impedance is so low.  If you want to continue using the Pignose, you need to insert a buffered bypass pedal between the audio probe and the Pignose so that the Pignose isn't loading the circuit under test.


Ok I can try that. Just trying to avoid having to work upstairs in the bedroom, or lugging an amp head and cab out to the garage.  I’ll try the buffer pedal first.


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## Chuck D. Bones (Apr 18, 2021)

Make sure you know what the input impedance is for that buffer pedal.  You can't tell with an ohmmeter, you have to inspect the schematic.


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## dlazzarini (Apr 18, 2021)

Chuck D. Bones said:


> Make sure you know what the input impedance is for that buffer pedal.  You can't tell with an ohmmeter, you have to inspect the schematic.


It’s a pedal I made with the klon buffer in it. Just the buffer and nothing else. Will that suffice?


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## dlazzarini (Apr 18, 2021)

music6000 said:


> Can you check for Continuity on the matching circles.
> View attachment 11100


I have just confirmed that I have continuity at all of these points.


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## dlazzarini (Apr 18, 2021)

Chuck D. Bones said:


> Make sure you know what the input impedance is for that buffer pedal.  You can't tell with an ohmmeter, you have to inspect the schematic.


Ok Chuck. I guess I’ve been having some senior moments. I’ve got one of those Positive Grid Spark amps that’s been sitting in my room for over a year. Totally forgot about. The audio probe should be ok going in to that one shouldn’t it? I tried it out but I don’t see a whole lot of change. I can definitely hear the signal better on lug 3 of the gain pot now but it’s still at a much lower volume than before R9.  I can definitely hear it better though


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## Chuck D. Bones (Apr 18, 2021)

dlazzarini said:


> It’s a pedal I made with the klon buffer in it. Just the buffer and nothing else. Will that suffice?


Yes, that will suffice.  The Klon buffer will load the circuit a little bit, but not so much that we get a false reading.



dlazzarini said:


> Ok Chuck. I guess I’ve been having some senior moments. I’ve got one of those Positive Grid Spark amps that’s been sitting in my room for over a year. Totally forgot about. The audio probe should be ok going in to that one shouldn’t it? I tried it out but I don’t see a whole lot of change. I can definitely hear the signal better on lug 3 of the gain pot now but it’s still at a much lower volume than before R9.  I can definitely hear it better though


Without a schematic, I can't be sure how the Spark amp is affecting the circuit we're testing.

When you probe pin 3 of the GAIN pot, does the volume change when you rotate the gain pot?


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## music6000 (Apr 18, 2021)

dlazzarini said:


> I have just confirmed that I have continuity at all of these points.


Cool, I wanted to know that Gain Pot from Leg 3 was Good, the trace stops & continues on the back of the board,
Chuck, you love a challenge & you have one!!!


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## Chuck D. Bones (Apr 18, 2021)

We're missing something obvious here...


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## music6000 (Apr 18, 2021)

I looked at all the resistors twice & they look good but their is some light reflection on them so....
Here is my go to Resistor Calculator so *dlazzarini, Can you confirm they are all correct :
68k is ?*
Click on Bands for 5 colour Bands








						Resistor Calculator
					

Resistor Calculator is an App developed by CherryJourney to help the user find the value of a resistor.




					resistor.cherryjourney.pt


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## dlazzarini (Apr 19, 2021)

I appreciate all your help guys. Tomorrow after work I’ll hit it again. I’ll triple check those resistors and I’ll verify if the gain pot changes volume when rotated. Thanks guys


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## dlazzarini (Apr 19, 2021)

I’ve got a question for you guys. I’m here at work but of course my overthinking brain is somewhere else.  Could I breadboard up the power section and just up to the point I’m stuck to see what I get there, or do I need to do the whole thing.


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## Chuck D. Bones (Apr 19, 2021)

That is a good way to go because you can make measurements on your breadboard and PedalPCB unit and compare.  I'd at least breadboard all of the JFET stages.


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## dlazzarini (Apr 19, 2021)

Chuck D. Bones said:


> That is a good way to go because you can make measurements on your breadboard and PedalPCB unit and compare.  I'd at least breadboard all of the JFET stages.


Ok I’ll get on it. I won’t be able to do it all today but I’ll get started. I’ve got some parts for restock showing up tomorrow


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## music6000 (Apr 19, 2021)

dlazzarini said:


> I’ve got a question for you guys. I’m here at work but of course my overthinking brain is somewhere else.  Could I breadboard up the power section and just up to the point I’m stuck to see what I get there, or do I need to do the whole thing.


Yep, But definately check all your resistor values to make sure, One stray one can screw the whole pedal!


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## dlazzarini (Apr 19, 2021)

music6000 said:


> Yep, But definately check all your resistor values to make sure, One stray one can screw the whole pedal!


I plan on it


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## dlazzarini (Apr 20, 2021)

Ok I’ve got it on the breadboard up to Q2. Waiting on my parts so I can continue, but I can tell you right that the problem is already apparent at Q1 on the pcb.  Q1 drain on the breadboard has a ton more gain than what I’m getting at Q1 drain on the pcb


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## dlazzarini (Apr 24, 2021)

Chuck D. Bones, music6000. Got the Monarch working as it should on the breadboard. Something is definitely going on early in the circuit. I’m not get near as much output off of Q1 as I am on the breadboard. The real wacky part is when I probe leg 3 of the volume pot while rotating it, it’s acting like the gain pot. All the way down cleans it up and all the way up I have gain. At the same time the gain pot is acting like the volume pot. All the way down cuts the sound. Turn it up and the volume comes up. Those controls are on complete opposite sides of the circuit. This thing is just messing with me now. I’m going to bed.


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## music6000 (Apr 24, 2021)

Can you do a Continuity test from Volume 1 to Ground.
Check Continuity on Volume 3 leg to C17 - 1uf.


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## dlazzarini (Apr 24, 2021)

Sure can. Vol 1 to ground I have no continuity. Vol 1 to C17 leg I do have continuity.


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