Pork Barrel Trouble

[rhcp311]

So, I just got done putting together my Pork Barrel, and I'm having some issues. The pedal works fine in bypass, but when I engage the effect, I only get my dry signal, and no chorus. When I try to hit the vibe switch, the signal dies entirely. I saw that another forum member had a similar problem to this, and his trouble was caused by buying a faulty MN3007. I got all of my ICs from Small Bear though, so I'm thinking that's not likely to be the issue.

I checked the orientation of all my parts though, and everything appears to be correct, and I double/triple checked my wiring, and everything appears good on that front too. I didn't make any parts substitutions, but the one thing I did differently was that I didn't use any SPST switches for the mods. For the Deep and Wet mods I used a SPDT toggle switch, and I just used the top two lugs, and left the bottom lug empty. For the Vibe mod though, I used a DPDT footswitch with the top two lugs on the left connected for the vibe mod, and for the right three lugs, I connected a spot to ground in the middle, and then I had one lug of a dual-color LED on the top, and another lug of the dual-color LED attached to bottom. If I did that correctly (and I'm pretty sure I did), then I figured I could turn the vibe on and off with a footswitch, and the LED would indicated whether the vibe or chorus was engaged by changing the color of the LED.

Also, even though I'm not getting a chorus effect, I still get clock noise. I don't know if that is helpful in any way, but it's something that's happening. I'm hoping the clock noise will get better once I get the effect working, but I'm not hopeful.

Any suggestions for what to try though? Is there any way to test my chip to see if it's bad?

Thanks in advance.

[jkokura]

It could be the chip, but if you didn't have any chorus effect at all but still had the signal when you flipped the vibe switch I'd suspect the chip more. I don't believe that's the problem.

What's more likely is that somewhere in your 'wet' path there's either a bad part or a bad solder joint. Do you know how to use an Audioprobe? I'd start at your output and trace back from there to find the problem. It could be as simple as cleaning up a solder joint, or replacing a pot.

Because what the Vibe switch does is cut the 'dry' signal, we know that the problem is somewhere on the wet signal path. Take a look at the schematic and see where the signal splits down to the MN chips? The wet signal starts at that 33n (c8) and then is blended into the main circuit at the mix pot. That whole section contains the problem somewhere. It's a crazy circuit to debug... good luck!

Jacob

[rhcp311]

It could be the chip, but if you didn't have any chorus effect at all but still had the signal when you flipped the vibe switch I'd suspect the chip more. I don't believe that's the problem.

What's more likely is that somewhere in your 'wet' path there's either a bad part or a bad solder joint. Do you know how to use an Audioprobe? I'd start at your output and trace back from there to find the problem. It could be as simple as cleaning up a solder joint, or replacing a pot.

Because what the Vibe switch does is cut the 'dry' signal, we know that the problem is somewhere on the wet signal path. Take a look at the schematic and see where the signal splits down to the MN chips? The wet signal starts at that 33n (c8) and then is blended into the main circuit at the mix pot. That whole section contains the problem somewhere. It's a crazy circuit to debug... good luck!

Jacob

Thanks for the help! Unfortunately, I don't have an audio probe, so I'm stuck using my multi-meter. Does anyone have a list of what the voltages should be? That would probably be the easiest way for me to double check. The transistors I used did look like the leads may have been bent a bit, so maybe I abused them in the past, and forgot about it, and accidentally used broken trannies? I dunno. A list of voltages to be expecting would be helpful though, if anyone has one. Thanks again!

[madbean]

You did not mention the trimpot. Have you tried adjusting it?

[rhcp311]

You did not mention the trimpot. Have you tried adjusting it?

Yeah. Sorry. I had my roommate play guitar while I adjusted the trim pot, and it didn't seem to change anything.

[rhcp311]

Again, if anyone had a list of the voltages I should be getting on my ICs and trannies, that would be awesome, and I would greatly appreciate it. I'd love to get this thing up and running, but I don't really know what values to expect..

[gtr2]

An audio probe is simple to make and you most likely have the parts to make one.

http://diy-fever.com/misc/audio-probe/

I use the 1/4" jack socket version so I can use a longer cable if needed.

I haven't built this so I'm not much help in that aspect.  But an audio probe is pretty essential to debugging some of the more complex effects and this is one of them...

josh-

[jkokura]

I'm going to agree. Voltages may help, but I'm not going to invade my build to get them for you. If you don't have an audio probe as I suggested earlier, then make one. I think that will help you much faster than the voltages will.

Jacob

[stecykmi]

you could check the obvious stuff before you try and build a probe, ie supply rails are 9v and 0v.

[rhcp311]

Thanks for the suggestions, guys. Looks like I may just have to build an audio probe at some point when I get free time.

I'm going to agree. Voltages may help, but I'm not going to invade my build to get them for you. If you don't have an audio probe as I suggested earlier, then make one. I think that will help you much faster than the voltages will.

Jacob

Sorry if it sounded like I was wanting someone to take apart their pedal and get voltages for me. I was just hoping that someone had happened to write them down as they were building the pedal (Madbean, for instance), so that I could do a quick spot check. Again, I wasn't trying to talk you into taking your pedal apart or anything!

[madbean]

I still owe some voltages on a Wolfshirt, so I will add this one too. I will get both of these done by tomorrow. I've been too distracted futzing around with an idea...time to buckle down and take care of business around here!

[rhcp311]

I still owe some voltages on a Wolfshirt, so I will add this one too. I will get both of these done by tomorrow. I've been too distracted futzing around with an idea...time to buckle down and take care of business around here!

So, I haven't had any time to build an audio probe or anything yet, since I had to trouble shoot two other things first, but if you ever had a chance to check those voltages, I'd appreciate it. Like I said, I have a feeling one of those transistors might be bad, so I'd just like to compare and see what I get, if you had a chance. If not, that's totally cool too.