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I have finally built my Paramix V4 – I’ve had it lying around for several years. After the off-board wiring nightmare (LOL) was finally over, I powered it up and…
ZERO SOUND OUTPUT. Not even a hiss. Nada.
Question 1: Shouldn’t there at least be sound coming out of the “Dry” send or the “Wet” send? – because in my case, there isn’t. Nothing out of the output jack, either. Does not matter if the foot switch is engaged, or isn’t. And I mean ZERO sound. NO hiss, not anything. BTW, I even used patch cables on both send/returns, even both loops at the same time to make sure the send/return loops were closed. ZERO SOUND from the output.
I have spent 7 hours troubleshooting: I’m not an electronics expert by any means so checking resistances and/or pinouts on the opamp are a bit out of my league, but this is a low-count PCB and checking to make sure resistor/capacitor values is not much of an issue. I’ve completely taken everything out of the enclosure, and gone over the PCB with a fine-tool comb looking for soldering bridges, wires in the wrong places, etc.
I did check on the backside of the PCB with my voltmeter to make sure the resistors are the right values, and they are.
I have checked, checked, and checked again that all the wiring is correct. I even re-flowed a few solders here and there. Nada. I removed the T-Diddy Boost Mod (OH NO!!) and wired it ‘normally’ – still not a sound, no change at all.
The LEDs for the foot switch and kill switch work and light up correctly.
I was wondering if the TL074 might be suspect: I only have two, so I replaced it with the other one I have. Still no sound (I think I got them both from Tayda long, long ago)
If someone says “Oh, yeah, definitely the TL074” then I’ll order more. Otherwise, I’m building a sound probe tomorrow (I should have done so a long time ago, but this is my very first build that hasn’t worked. This is pedal build #13. I’ve also wired up 6 guitars and 3 basses without any issues. I’m not saying I’m an electronics expert by any means…but I’m decent with my Hakko) and I guess I’ll spend another hour or two on it.
Thanks for any help/ideas.
I thought of that, believe me. The off board wiring though…its like looking at an exploded bowl of spaghetti. Not a lot to see through the many, many wires on this puppy.
Johnysomke, you might be surprised at how good some of the Admins/Members of this forum are with seeing a couple of pictures. Sure as heck can’t hurt. Just sayin’. 😉
Johnnysmoke,
My first check whenever a pedal doesn’t make any noise, is the input and output cables, go direct guitar to amp through both cables. That verifies the guitar and cables and amp.
Try plugging the guitar into the returns then, If you get sound, then your problem is in the front half of the circuit.
Then check voltage (DC) on the board, at the 9v+ pad and a ground. if that is good then verify the bias voltage (VB) that would be at pins 3, 5, and 10 on the IC, that should usually be around half the supply voltage, 4.5 volts. while your there write down the voltage readings for the other pins. pin 4 should be 9v. pin 11 should be 0v. NOTE: the pin to the left of the dot on the IC is 1 and you count down and over then back up..
If nothing obvious is wrong ,at this pint I would break out the audio probe. I’m not one of the guru’s here.This is where they take over.
Remember those folks that build their pedals all neat and tidy, are artists, I’m not one of them, It doesn’t matter what it looks like, as long as it works..Post some pictures and the voltage measurements..
With two not-so-subtle hints to post pix (LOL) I’ve pulled the PCB out of the housing for the third time, and I’ve taken pictures of my spaghetti bowl. I really hope it helps, because I’m at wit’s end. I’ve had to restrain myself from throwing it in the bin a few times…my wife talked me off the ledge last night. She is the soothing Yin to my raging Yang (Simpsons reference).
PSA: If anything, I’ve now learned to use a smaller gauge wire for my off-board wiring. At first I was trying to make a super neat and tidy pedal, being jealous of other’s gut shots. After wondering why my rather huge pedal housing is STUFFED I finally realized that the wiring I used was so thick, it just made a mess of everything. I finally had that “ah-ha” moment and realized from now on, I’ll use the Barry’s Hookup wire I have on hand.
Ladies and gentlemen, I present to you photos fresh off my phone at 6:32AM:
EDIT: for anyone looking at my pictures, those silver dots on the bottom are from a silver sharpie I used to mark the locations of the resistors when I was testing them with my voltmeter. Just FYI
“My first check whenever a pedal doesn’t make any noise, is the input and output cables, go direct guitar to amp through both cables. That verifies the guitar and cables and amp.”
I’ve actually done that twice. I made sure my guitar and patch cables were 100% working, along with pedals, etc. that I’ve used for troubleshooting. TLDR: about 5 years ago, I was ‘troubleshooting’ why my 1975 Kustom guitar amp wasn’t working, I think it took me 40 minutes to figure out it was a dead cable I had plugged in. I should have known: that cable was used on a tour in the 90’s and was…very abused. LOL.
“Try plugging the guitar into the returns then, If you get sound, then your problem is in the front half of the circuit.”
Thank you! – That was an excellent idea. Forehead slap “why didn’t I think of that?” – unfortunately, the returns did not work, either. I tried the input, the sends, and the returns this morning again: not even a hiss. Nothing. Dead. I’m thinking this MUST be something stupid I’m doing, I’ve got to have something grounded somewhere…
“Then check voltage (DC) on the board, at the 9v+ pad and a ground. if that is good then verify the bias voltage (VB) that would be at pins 3, 5, and 10 on the IC, that should usually be around half the supply voltage, 4.5 volts. while your there write down the voltage readings for the other pins. pin 4 should be 9v. pin 11 should be 0v. NOTE: the pin to the left of the dot on the IC is 1 and you count down and over then back up..”
Thank you again: I knew I could do a voltage check on the IC pins…I just didn’t know which ones to check. Measurements are as follows:
Pad/Ground: 9.45v
Pin 3: 4.69V
Pin 5: 4.69V
Pin 10: 4.69V
Pin 4: 9.46V
I have made all measurements 3x to make sure they are consistent.
“If nothing obvious is wrong ,at this pint I would break out the audio probe. I’m not one of the guru’s here. This is where they take over.”
I’m going to make a probe later this morning, I have the parts ready and sitting on my bench, but I have to go back to bed for now and get some more sleep.
“Remember those folks that build their pedals all neat and tidy, are artists, I’m not one of them, It doesn’t matter what it looks like, as long as it works..Post some pictures and the voltage measurements..”
Your advice is sage. Done, and done. Thank you again.
I just know, deep in the back of my feeble brain, that I’ve done SOMETHING fundamentally stupid with this, and that’s why it’s not working. LOL. I just made sure that yes, in/out jack sleeves are to board, tips to foot switch. I thought it would be ‘hilarious’ had I reverse-wired the output jack, but it’s not. I’ve gone over the wiring on this thing about 100 times…this has to be something I’m overlooking with my reading glasses on. LOL
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