Death of a Sunking

[RobA]

You need to check the op amp voltages with the op amps on board to get the voltages on all the pins. You could check just the supply pins at the pads with no op amps in place to get the levels there.

The resistor just needs to be put in front of the power input. You could actually just solder it in to the lead the same way you might for an indicator LED resistor. For now though, as long as the zener is up there in the 12V range and your input is at 9V, that shouldn't be an issue.

[MattL]

I just discovered that I had erroneously put a 39n instead of a 390n for C4. Two questions:
1. the pedal had still sounded very good...is this a capacitor not relevant to the sound, and
2. could this be the cause of the pedal blowing?

[RobA]

Just to be sure we are looking at the same thing, the schematic I have is for the V3 doc and it shows the 390nF cap being C5 (C4 is 68nF). It is going to have an influence on the sound of the pedal. It's going to change the frequency response as the gain is changed.  Although, this is going to be a pretty complex thing since the gain structures of the two stages are intermixed and there's multiple feedback points involved. So, without simulating it, I really don't know how much it'll alter the sound. I wouldn't think that this by itself would have anything to do with the pedal blowing.

Did you make any other parts substitutions? I can't remember the whole conversation in the thread going back at this point, did you get the voltages on the IC's?

[MattL]

Just to be sure we are looking at the same thing, the schematic I have is for the V3 doc and it shows the 390nF cap being C5 (C4 is 68nF). It is going to have an influence on the sound of the pedal. It's going to change the frequency response as the gain is changed.  Although, this is going to be a pretty complex thing since the gain structures of the two stages are intermixed and there's multiple feedback points involved. So, without simulating it, I really don't know how much it'll alter the sound. I wouldn't think that this by itself would have anything to do with the pedal blowing.

Did you make any other parts substitutions? I can't remember the whole conversation in the thread going back at this point, did you get the voltages on the IC's?

Not yet...I started building the second board. It was actually as I started to fill the BOM of a Guitarpcb.com miniklon that I discovered I didn't have the 350nf, nor was there evidence that I had. So I checked back on the other build, and noticed I'd used the wrong value in both Sunkings. I have some on order anyway. I haven't gotten back to the other one because I kind of gave it up in favor of a new one, since I had two boards, and I needed to "borrow" the pots. I am going to get back to it...I have replacement pots on order too, and I value and appreciate all your help and information...thanks!

[RobA]

It certainly can't hurt to build it again. Which IC do you have for the charge pump.

[ch1naski]

If you liked the sound with the smaller value cap, maybe you should socket it in the next build. Just in case your  "erroneous" ;)version sounds better to your ears than the stock cap

Sent from my Nexus 7 using Tapatalk 2

[MattL]

If you liked the sound with the smaller value cap, maybe you should socket it in the next build. Just in case your  "erroneous" ;)version sounds better to your ears than the stock cap

Sent from my Nexus 7 using Tapatalk 2

Good suggestion, thanks!

[MattL]

It certainly can't hurt to build it again. Which IC do you have for the charge pump.

MAX1044. Since none of the components hadn't been replaced that were in question, meaning all IC's, as well as diode 3, I'm at a loss. All solder has been re-flowed. Anything else that can blow other than these things? Some people have mentioned other component failure, but every time I suggest component failure on the forum, people act like I'm an idiot, and say components almost never fail.

[MattL]

It certainly can't hurt to build it again. Which IC do you have for the charge pump.

MAX1044. Since none of the components hadn't been replaced that were in question, meaning all IC's, as well as diode 3, I'm at a loss. All solder has been re-flowed. Anything else that can blow other than these things? Some people have mentioned other component failure, but every time I suggest component failure on the forum, people act like I'm an idiot, and say components almost never fail.

To clarify, all of those components HAVE been replaced!

[rullywowr]

I have replaced diode 3 to no effect. Also, when hooked up to my test rig, with effect engaged, I don't hear anything that I'm supposed to, like guitar, but I notice the gain control can be heard to increase or decrease hiss, which makes me quess that the output is working.

Are you testing the board inside the enclosure still?  I would suggest taking it out if you haven't already and checking over the outboard wiring.  Since the wiring is particular on this build you want to make sure you have everything right.  From your description, it does sound like the output is working however it could be something as simple as a shorted or not connected ground on the input jack.  Especially if you used the housing as a ground and didn't run a ground wire from the sleeve of each 1/4" jack.

If that fails, then I would whip up a simple audio probe out of a 1/4" guitar cable.  Tie the sleeve to ground and use the tip as a probe (with a solid wire or something).  Plug this cable into your amp or whatever.  Trace the input signal from the "IN" pad and follow it through the circuit.  At some point it will cut out and then you can narrow down your potential issue.

Also check voltages on all the IC's respective pin (usually pin .  If you got nothing, it would suggest a problem with the power supply or feed circuit.

[MattL]

I've actually tried in and out of the enclosure...I have a test rig, thanks to the wisdom of the fine people on this site? I didn't choose the more specific wiring, the buffered version, but instead went for the true bypass version, ala the stock Madbean version. Lots of time I use the more standard method of true bypass, the popular "easy" version with star grounding...I may try that, unless anyone has a reason it shouldn't work. That one I feel comfortable with, as I have it memorized. I was getting close with the Madbean version, before I went on my unplanned pedal building hiatus (to build guitars). I don't think it matters which of those I use, but I don't want to get involved in the buffered version...i see no point. I don't use super long cables, etc. But I digress! Anyway, the pedal had been sold and used regularly for at least six months before it blew, so having reflowed all the solder and replaced the suspect components, I'm a bit at a loss. I'm finished with the second board, just waiting for the 390nf cap.