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Hi
I’m looking for help and advice, this is my first attempt (and maybe my last)
I’m building the Muff’n Ram’s Head variant (with only one modification – the on-off-on switch at SW1 – mod 6) but currently have to turn all pots to maximum and my amp to full vol to hear any fuzz (its there but extremely quiet)
Also SW1 seems to do nothing (I don’t even get the LED diodes lighting)
I am using a reliable 9v power source. The pedal powers on via the 3PDT switch and bypass mode works just fine. I have 9v on the board. I’ve checked the transistors and they look good. I am using the 2N5088 stock transistors and I’ve orientated them I think correctly as per the instructions and silkscreen.
The pots do seem to work as when I turn down the vol the effect goes (very quickly), the tone seems to change and Sus also.
All jumpers have been done.
Transistor values are as follows:
Q1- 1) 1.41 2) 0.69 3) 0.08
Q2- 1) 4.24 2) 0.66 3) 0.06
Q3- 1) 3.89 2) 0.62 3) 0.04
Q4- 1) 4.13. 2) 1.53 3) 1.06
I have reflowed my solder a few times
After probing the board the only anomaly I can find is R1 and R3 don’t connect to ground as the schematic would suggest.
I have attached the pots with wires to avoid breaking the pins with constant bending to check the board
Diodes and resistors checked before applying to the board.
I am at a loss as to what to do now.
Any help or suggestions would be greatly appreciated.
I’ve just tried a jumper from R1 & R3 to a ground pad but it has made no difference unfortunately
I would start by reflowing the entire project.
I see a lot of dull solder joints and a few pads lacking solder.
Flip it over and reflow all board solder joints one at a time and have some solder handy while doing it. Your solder joints should be like tiny little shiny Hershey kisses and not flat, dull, or sunken in.
Take your time. Don’t overdo it with solder either. Just one bad solder joint will cause a board not to work.
The ones circled below initially jump out at me but I would slowly and carefully reflow the entire project using a conical tip.
Never mind the two on the left as I see that is an intentionally uninstalled resistor. You have the best view of your board so try and make all your solder joints as I described.
Ok Thanks, I will reflow the board and report back.
Hi again
So I have taken my time, wicked the old solder and reflowed new solder as you can see. There is a definite improvement, but I still have to turn my amp up all the way and the volume pot all the way to get Fuzz, and on bypass its deafening.
Also the SW1 still doesn’t do anything (and no LED lighting on D3 or D4 which I assume should be happening)
Any other suggestions or soldering improvements?
Hey TPH77. I just did a green Russian with that board yesterday. One little issue of my own and then good to go. Troubleshooting is about eliminating possibilities. Is it possible that the transistors are not making good contact? Are they each proven to be good? Is the strange R1 and R3 phenomenon resolved? Is SW1 bad perhaps? I’ve met a lot of crappy switches and always after install. Have you triple checked all resistor and cap values? Double checking is not enough often times. Ask any one of my fiber optic techs. I would scrub both sides well with alcohol and a toothbrush. Make sure there are no tiny solder bridges or stray wire ends making contact. (Personally my guess is something is touching where it should not). A toothpick for a tool works well. Sometimes when inserting stranded wire through small holes a strand goes rogue and invisibly touches something nearby (one of my personal favorites). Make sure resistors aren’t touching each other or have metal touching them for any other component. Unwanted contact can occur when the paint is chipped or cracked.
First I see that you have a very low voltage to Q1. The collector of Q1 and Q3 should measure the same. Each is fed source voltage through a 100R and then 22K resistor. I would fix that first and make sure my voltages make sense and go from there. Personally I don’t trust your ‘reliable’ power supply. I need to troubleshoot with a good battery for my own peace of mind. That’s up to you tho. Make an audio probe as soon as possible so you can zero in on issues. You can google some easy designs. It will help answer a lot of questions before they are asked. Asking questions is still, of course, ok any time. Just saying my DMM and test probe will usually find my problems pretty quick. Let us know how things go.
Since Playsforfun mentioned the voltage in Q1 that I overlooked, I quickly glanced at your value for R5 and you have a 47k instead of a 470k.
It looks like you did the same thing for R10 and R15. Also, R19 should be 470k.
I would recheck all values on your board again.
Urgh
thanks for the advice. I will go through it and check check the components! I’ll feed back when done. Looks like I could be a while!
(Muff’n – Rams Head Variant)
Ok I’m making real progress (I now have Fuzz) so thank you, however, SW1 still does nothing and the LED Clipping diodes do not light up as I would expect.
So this is what I have done so far:
– Lifted all resistors and checked and double checked values with DMM – All were in fact correct!
– Replaced all Capacitors with new ones (values checked and double checked)
– Reflowed solder, ensured no bridging solder, stray wires, no components touching etc as advised
– Scrubbed both sides with Alcohol (Tooth Brush)
– Transistors tested with DMM seem good
– On-Off-On Switch on SW1 also replaced with a new one that looks good with DMM – no difference
– R1 & R3 are still not grounded as the schematic would suggest, and this was also true when I removed the resistors, the PCB at R1 & R3 also did not connect to ground.
– also I replaced C1 with a 1microF cap (the list states it should be a 10microF cap but the kit didn’t come with one and I read on the forum this was a mistake – so am I correct in doing this? (I did this a while ago with the first build so isn’t the reason for the dramatic improvement)Here are my Transistor Values now:
Q1. 1) 1.37 2) 0.69 3) 0.08
Q2. 1) 4.23 2) 0.65 3) 0.06
Q3. 1) 3.86 2) 0.62 3) 0.04
Q4. 1) 4.10 2) 1.53 3) 1.06Seems much better but Q1 doesn’t seem right. I wasn’t sure how you (@playforfun) suggested Q1 & Q3 Collector values should be the same (each fed source voltage through a 100R (R26) and the 22k resistor (? Here is where I am confused as my reading is Q1 is via a 15k (R6) and Q3 via a 10k(R16))
For your information my reliable power source is my power bank for all my pedals, I have also used a new 9v battery – it made no difference.
I have now made an audio probe and tested it. Having not used one before, can I ask if it is normal to have different volumes on each side of a resistor, each leg of the transistor etc? As I trace through the board via the schematics am I looking for absolutely no output from the probe on components (that are not grounded obviously)So my questions are:
1). Should R1 & R3 be grounded as per the schematic? If so could this be an issue with the board (Board didn’t go to ground at R1 & R3 with components removed?
2). Should I run a trace to ground at R1 & R3? Or is this not necessary?
3). Am I correct in putting a 1microF Cap at C1?
4) Do my Q values (esp Q1 collector value) look good?
5). Can you clarify regarding audio probing if different volumes/amount of distortion are expected? Am I looking for absolutely no output from a component?
Sorry for all the questions, but a really appreciate all the help you’ve given me as I feel I’m nearly there. I will go over the board tomorrow with the audio probe and see what I can find.
Thanks againFirst things first. Clarify this comment for me, please.
“Ok I’m making real progress (I now have Fuzz) so thank you”
Does it mean you have more volume now than before? More fuzz than before? Both?
You said in your first post you had fuzz but the volume was “extremely quiet”
“turn all pots to maximum and my amp to full vol to hear any fuzz (its there but extremely quiet)”
Please elaborate on what has changed.
“Should R1 & R3 be grounded as per the schematic?”
Yes. The pads are connected directly to the ground plane (no trace). It sounds like the pads are damaged. Before you can expect anything else to work, you must correct the problem to Q1 which is the very beginning of the circuit. You will have to find a way to connect the bottom pad of both R1 and R3 back to the ground if it is not just a bad solder joint. You probably want to try another reflow first.
Note on your original photo (reposted below, zoomed in) these would be the pads just above the M1 and M2 sections. The solder joints for both pads are not soldered properly likely resulting in a cold solder joint. Your reflow looked very good to me but it was not necessary to remove the original solder (which might damage the pads) A reflow is just reheating the original solder and perhaps adding a touch more.
Thanks @Barry for replying.
so I have lots of volume now (it’s really loud) with may be a little bit more fuzz than I was getting before (but it is hard to tell as it was so quiet before) it’s now louder than on bypassok I will first reflow those solder joints but I think the pads must be damaged as they did not go to ground with either of the resistors removed. It was an issue I had noticed going back to before me contacting the forum, so they had only been soldered once.
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@Barry I tried reflowing R1 & 3 but no joy connecting to ground. So I threw a jumper to ground from the pads just above M1, they are now grounded.
no effect on SW1 however but I still have good volume and fuzz.transistor values now:
Q1 1) 0.02 2) 0.59 3) 6.79
Q2 1) 0.06 2) 0.66 3) 4.24
Q3 1) 0.04 2) 0.62 3) 3.90
Q4. 1) 1.07 2) 1.54 3) 4.13
what to do next?
am I correct about replacing C1 with a 1 microF Cap?
should I audio probe next?
thanks
Sorry got those transistor values the wrong way around.They should be:
1) = collector, 2) = Base. 3) = emitter
Q1 1) 6.79 2) 0.59 3) 0.02
Q2 1) 4.24 2) 0.66 3) 0.06
Q3 1) 3.90 2) 0.62 3) 0.04
Q4. 1) 4.13 2) 1.54 3) 1.07
For C1 you can use anything from 100nF (0.1uF) clear up to 220nF or even larger for bass or baritone guitars and there will be no difference sonically as any of those will allow all standard guitar frequencies through regardless.
As for the clipping switch, it is only a subtle difference when combining Silicon with LED. The biggest difference would be just opamp but again there is still a lot of clipping happening anyway so it is not a huge difference. The differences would be more noticeable at louder volumes.
You might try just using an SPDT on/on or removing it altogether.
Other than that I am not sure what else I can suggest for the clipping switch.
It is good that you have a working circuit now.
ok thanks @Barry for all the help and guidance.
I just expected to see the LED diodes lighting up when using LED clipping and some obvious difference in sound.
if it’s only a very subtle difference and the LED diodes are not expected to light up, then I guess I’m done.
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