Hey Brosiffs! I built my 2nd Mudbunny, and am getting that classic loud pop when I engage the effect. I don't remember the first build doing this, but I could be way wrong (had my amp up pretty loud last night). Anyways, from my novice vantage point I looked at the schem and it looks like R1 is acting as a pulldown resistor. I also added a 1 meg resistor on the switch from input lug to ground to see if that would help, but it din't seem to work out. I figured I would run it by you guys before I submitted to the fact that thats just the way it is.
Also is it normal to loose a little volume when turning the tone control CW? I built the board to Green Russian specs. Anyways, I hope all you cholos & cholas are getting ready to watch Yasiel Puig dominate the Home Run Derby tonight!
Stay PUnk!
No, volume loss isn't normal. If you put that 1m across the inout jack from tip to sleeve, that will work as a pulldown. My mudbunny doesn't pop either, may need to start a debugging thread, also does it happen on every amp with every guitar?
You should not lose volume with the tone pot. In fact, when you turn it clockwise you will perceive it as louder when working correctly. This is actually more of an auditory illusion due to how our ears hear high and low frequencies.
Also, let me caution against putting a 1M resistor on the input jack as jimilee suggested. Doing so would introduce the resistor into your bypass signal which could load your bypass signal. There is already a pulldown on the circuit board so this should not be necessary.
Quote from: madbean on July 15, 2014, 01:08:17 AM
You should not lose volume with the tone pot. In fact, when you turn it clockwise you will perceive it as louder when working correctly. This is actually more of an auditory illusion due to how our ears hear high and low frequencies.
Also, let me caution against putting a 1M resistor on the input jack as jimilee suggested. Doing so would introduce the resistor into your bypass signal which could load your bypass signal. There is already a pulldown on the circuit board so this should not be necessary.
Yep, I thought about that, and with a pull down in there already, there's a bigger problem, leaky cap?
Check your input and output caps are the right way around. This has got me a few times before...
I brought it to work today and am going to plug it into some different amps and axes and see if it is still doing it. Thanks Jimilee!
Quote from: jimilee on July 15, 2014, 01:00:57 AM
No, volume loss isn't normal. If you put that 1m across the inout jack from tip to sleeve, that will work as a pulldown. My mudbunny doesn't pop either, may need to start a debugging thread, also does it happen on every amp with every guitar?
Yea I was kinda thinking that. I mean I just built one a couple weeks ago for my friends B-day and don't remember any of these problems. Just need to figure out what i did wrong!
Quote from: madbean on July 15, 2014, 01:08:17 AM
You should not lose volume with the tone pot. In fact, when you turn it clockwise you will perceive it as louder when working correctly. This is actually more of an auditory illusion due to how our ears hear high and low frequencies.
Also, let me caution against putting a 1M resistor on the input jack as jimilee suggested. Doing so would introduce the resistor into your bypass signal which could load your bypass signal. There is already a pulldown on the circuit board so this should not be necessary.
Hey you guys have anymore suggestions on the tone control dropping volume when I turn it clockwise? Which should really be perceived as louder. I broke out the schem and checked all the components around the tone control and everything looked good. I double checked all the resistor values. How would one check for a leaky cap? I realized it is way easier to trouble shoot a pedal when there is absolutely no sound vs pretty much works perfectly but one minor thing. Anyways if anyone has any suggestions let me know. If not no worries, I'll keep plugging away! Thanks homies!!
Not, it's less frustrating when there's no sons than when there is. Have you checked for solder bridges and cold joints?
Good point. Now that I think about it, it can be pretty demoralizing when no sound comes out. I took my testing rig from Jacobs site and the schematic and probed every joint and component in order and everything that was suppose to get signal passed signal and everything that was suppose to be ground or power was that. I guess if there was a leaky cap, you would still get signal? I'm gonna try again after bowling League tonight.
I'm gonna recheck the values as well. Maybe a once over on all the joints ain't a bad idea too. Thanks jimilee!
Quote from: jimilee on July 28, 2014, 12:24:56 AM
Not, it's less frustrating when there's no sons than when there is. Have you checked for solder bridges and cold joints?
I was thinking about just desoldering all the components near and around the tone pot and resolder all new fresh components and see if that fixed the volume loss on the tone pot problem. If that doesnt work I may have to walk away from this one for a while. This one has really got the best of me. I think the worst part is that I successfully built a great one a month before...Anyways, stay up playas!
Did you ever figure out the popping problem?
I'm having the same issue myself. I have the 2013 edition, and I couldn't find a wiring diagram so I used the old one, which is cool except there is an extra ground connection (or at least I think so) on the 2013 ed. the ground connection between the input and output leads wasn't connected initially. I've now connected it to the center-bottom of the switch and it still pops.
Do i need to worry about stuff grounding to the case?
-c
Honestly I cant remember? From re-reading my previous post it looks like I may have walked away in frustration. I was having problems with the tone pot too. That build was all kinds of messed up. Ill pull it out and check it when I get home tonight and let you know if I ever figured it out.
Quote from: hubb on November 18, 2014, 01:35:52 AM
Did you ever figure out the popping problem?
I'm having the same issue myself. I have the 2013 edition, and I couldn't find a wiring diagram so I used the old one, which is cool except there is an extra ground connection (or at least I think so) on the 2013 ed. the ground connection between the input and output leads wasn't connected initially. I've now connected it to the center-bottom of the switch and it still pops.
Do i need to worry about stuff grounding to the case?
-c
Quote from: hubb on November 18, 2014, 01:35:52 AM
Did you ever figure out the popping problem?
I'm having the same issue myself. I have the 2013 edition, and I couldn't find a wiring diagram so I used the old one, which is cool except there is an extra ground connection (or at least I think so) on the 2013 ed. the ground connection between the input and output leads wasn't connected initially. I've now connected it to the center-bottom of the switch and it still pops.
Do i need to worry about stuff grounding to the case?
-c
I'm not sure that I understand you correctly but here's a few things on ground:
your enclosure is supposed to be on ground level. Use a multimeter (continuity checker or voltmeter) and check if your enclosure is on ground if you're not sure. Metal framed jacks, which are most commonly used, are connect the enclosure to the sleeve, which is ground.
There are often more ground pads on the board than are really necessary. They are there for your convenience as builders will have their power jacks at top or side or use isolated jacks. Normally you just need one to hook up the ground from the power plug, one to go to the stomp (or not, you can wire it from the plug too if you want) and maybe one or two for in/out jacks (as I said, normally they connect the enclosure to ground and therefore the other jack's sleeve too, so one would suffice).
As you can see, there are many ways to hook up the ground properly, so it might just be that you have a spare pad on the board.
hope that helps, cheers
Thanks for the clarification. I wired up both ground pads and the jacks are metal. I'll test them for ground.
I'll look for some solder bridges too, check the switch wiring.
Thanks again guys.
Might just be the 3pdt. I had a bad one that gave a pop when engaged. I could feel the difference between the bad one and a good one. Give it a push with your finger, see if you feel two clicks instead of the usual single click. I changed out the switch and the pop was gone.
Murdog,
Great tip! The switch wasn't defective but I had forgotten to solder the bottom left lead. Once that was fixed, the popping was resolved.
I had to offboard the tone pot because of the knobs I wanted to run and I think I torched it. After I replaced the tone pot the pedal seems to work, however the volume is super low, and it seems the volume fluctuates (dips and swells) without any interaction.
I'll search around to see if other posts have tips on the dipping and swelling. Thanks again!
No luck finding anything.
I thought it might be a good idea to record the voltage at the transistors. Perhaps someone can comprehend what they mean.
They're all consistent, which is cool. . . . i think
q1
e 2.7 v
b .466v
c 2.6 mv
q2
e 2.7v
b .46v
c 2.8mv
q3
e 2.5v
b .44v
c 1.1mv
q4
e 2.7v
b .49v
c 20.3mv
And just to ensure that i'm doing it right, i'm testing these voltages by turning on the pedal, and touching my black lead of my multimeter to the negative lead on the power jack, and the positive lead to each leg of the transistors.
I read somewhere that transistors are linear amplifiers. . . . so if the "e" on my 5088 is the output, are they all working right?
Appreciate the help. . .
-Chris
I think i got it!
I triple-checked for solder bridges and found none.
I checked the values of all of the caps and found they were all correct.
I started checking the resistor values and it turns out I had installed a 100k resistor in R24 instead of the recommended 100R resistor.
In the process of swapping out the resistor i jacked up a bunch of wire connections so I'll be able to fix it and test it out tomorrow.
I don't know anything about how circuits work, but i'll draw a few conclusions just based upon some observations / assumptions.
1) Resistors restrict current and thus reduce voltage (thanks google)
2) R24 is the first resistor from the 9v in (based upon my attempt to understand the schematic)
3) The entire circut was running at a lower voltage than intended, thus the reduced volume
4) I bet my transistor voltages were all low (not sure what they should be)
I'll post again if the fix works. If someone could confirm/correct this stuff ^^^ I'd appreciate it.
Thanks!
-Chris
You only have to do that (switch K for R) about ten times before you triple check those pesky letters! And then you'll do it again anyway.. Very common mistake.
Glad you got it fixed.