@playsforfun
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That would make sense since the input seems to go to ground. Switch lugs should have a horizontal position as the works of the switch are in vertical columns. For everyone else reading this, please go make an audio probe. Take Johnnysmoke’s word for it. It’s nifty.
“Nothing out of the output jack, either. Does not matter if the foot switch is engaged, or isn’t.”
So you don’t have ‘bypass’ but the led works. Something silly is happening. Don’t fret yet.
“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”
You say you’ve checked resistances. Does the meter check continuity? Because you have some checking to do.
“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.”
Your pictures say otherwise and haven’t been useful so far. If you want to give us good and totally in focus pictures, you will have to remove it completely and spread it out so we can follow wires, even though you have done it 30 times. What is your color code?
“The LEDs for the foot switch and kill switch work and light up correctly.”
Let’s take a moment to count our blessings. Two.
“I was wondering if the TL074 might be suspect”
Seems like it. An audio probe would give most of the answer. Find a ‘good’ TL074 from another pedal, perhaps, and swap it in. Check for bent legs (pins).
“I’ve had to restrain myself from throwing it in the bin a few times…”
Don’t do that. The board looks plenty fine. I would be tempted to de-solder and clean all jacks. Then install the jacks into the closure and solder them properly while in place after you trimmed the excess wire. Neatness isn’t art. It’s just smart. But that’s just me.
“I’ll use the Barry’s Hookup wire I have on hand.”
Then order more or 24 gauge pre-tinned. I prefer stranded but solid works too.
“Also posted IC voltages. Thank you!”
Some. But a full accounting would be better. Here are mine:
Input voltage 8.75 vdc
1: 4.37 14: 4.37
2: 4.37 13: 4.37
3: 4.37 12: 3.98
4: 8.74 11: 0.00
5: 4.36 10: 3.98
6: 4.36 9: 4.37
7: 4.36 8: 4.37
All my troubleshooting leads and wires are in excellent condition, kept separate, and proven to work prior to troubleshooting.
I have ground continuity everywhere I should according to the schematic using my DMM.
I have ‘bypass’ through my in and out jacks and ‘power switch’ when Paramix is inactive.
If your success rate is as you say then you are way better than me. Mistakes with all this wiring are easy to make. Since you have done the T-Ditty Boost mod, you are aware of the v4.5 build document. Directly after the mod, starts the additional troubleshooting points from Tonmann. He is awesome. Complete that guide as laid out and you will be well off. Follow it up with an audio probe after reinstalling the chip. We can help. But you actually have to have one. So simple to make. It doesn’t need to be fancy. A guitar cord, a wire and a capacitor will get you there. Let us know when you are ready to proceed. We can walk you through it systematically.
I love me some Stage 3 too. I put that **** in everything. Nice looker Steve.
MathU41, They both invert the signal if that is important. Otherwise different, and a large (too large to inject in someone else’s post) rabbit hole , but well worth investigating.
Before taking yes for an answer, check out some of this information.
A can be chosen for a gentler sweep when B just seems to make things happen too quickly. They both have the same results somewhere along the sweep.
I can’t say for sure what your situation is yet but, for the handful of times I experienced this, it was always the 3PDT switch and usually a pita to change out. Not to mention the cost. But for reasons beyond my knowledge, it was the switch. One time one fell apart shortly after removing it while messing with it. You never know with the switches and pots until you try them. All sourced by me. No one to blame. Everyone’s results may vary. But that has been my experience so far.
Nice project. The led and clr possibility is there if you need it. If you don’t you can ignore it. Which could also mean that you don’t need power or ground either unless passing them through to another board. Or maybe using one for a star ground or 9v distribution. So the 3PDT board (best in the industry) is a switch board PLUS all those other things. Happy building.
OK great. So the PURP is good to go. I would suggest starting a support thread for the Tone TwEQ complete with all the clear photos and voltages that we like and we can help figure it out.
R7 can be tested properly by lifting one side to remove it from the circuit.
A quote from Cybercow “The 2N7000 devices are just for hard clipping. The circuit will work with or without them. It will simply be louder and cleaner without the 2N7000s. D1 is just part of the hard clipping configuration to provide asymmetric clipping. Just make sure it’s oriented properly. If it’s not, it just won’t clip right”
With the mosfets in place you are hearing the result of the voltage interference between pins one and five and C1 and pin three. Sorry. But have you measured the gain resistance? And does the gain function work properly? Less resistance – less gain? Not every pot is a good one. With the mosfets removed what are your results?
Welcome to the forum MG. Here is a good explanation right from the designer himself. Happy building.
If you follow along in the schematic your audio path should be input >C1 >R2 to pin 3 of IC1A. Pin 1 >R6 >R7 to pin 5 of IC1B. Pin 7 >C7 >R10 to Vol tab 3. The other components affect either the voltage or frequencies within the overall audio signal. Mostly the unwanted ones.
Pin 1 (an output) should be louder than pin 3 (the input) because of the resistance of the gain control combined with R5, and in relation with R4, causing the amplification to happen. Same with pins 5 (input) and pin 7 (output) because of R8 and R9. Pin 7 should be loudest spot if you had a way to measure that. R10 quiets it. R11 reduces that quieting and the Volume makes that signal quieter. Hopefully all that makes sense.
I want to retract what I said about the circuit working with the diodes removed. That is in fact the path that VB voltage takes to pin 5, so they will need to be installed properly.
You may be going a little too fast, Mickey. Lets start with two working boards before combining them. I don’t see anything wrong but I can’t see much from your photo. You may need to start a build support thread.
Hello VR and welcome to the forum. Very nice drawing BTW. One reliable ground wire is fine for the buffer board. I’m not sure what the solution is you are looking for nor the problem but 2 questions arise for me about the drawing. First, is that a reliable and measured 9v source? Second, does the Effect Input NEED to be grounded during bypass? Barry’s board won’t support that ground connection. During bypass the Effect Input will experience an open situation as opposed to grounded. If that’s cool I think it should work. Certain circuits require the input be grounded during bypass to block unwanted noises.
Google, my friend.
Those seem fine to me. The circuit should also sound good with Q1, Q2 and D1 removed and the boost switch open. Q1, Q2 and D1 just provide clipping for the overdriven sound. BTW which mosfets did you use and did you verify the pinout (can’t see them)? What are you using for D1 diode? I would measure voltages again at the op amp with all knobs fully CCW, as is normally done, and again with the IC removed, just for reference.
Since I see some ‘slag’ here and there on your boards my guess tends toward signal loss from solder bridge. I would take a tooth pick and rub it between all solder pads that are close and shouldn’t touch and clean off anything that shouldn’t be there. Check carefully under the pots that are in place. Your soldering itself looks mint. I would reflow off- board connections, though, as these fail with cold solder joints far more often than others. For example I’ve pulled wires right from jacks that looked great but weren’t. Maybe I was in a hurry that soldering day or it wasn’t Barry’s wire. And pay extra attention to on-board ground pads because they usually take extra heat to melt the solder due to the size of the copper plane within the circuit board design taking longer to heat up fully. You can see what I mean when you try to shine light through Barry’s boards. Some of the invisible connections inside are large and take an extra second or two of soldering iron. A cold joint can have a partial connection resulting in weird outputs. I give a lesson because I’m hoping there are more eyes reading this than just yours and mine.
Beyond that and more guessing an audio probe is your best tool. It will reveal the bad area when expected signal isn’t there. Mine is kept handy in the bin marked test tools.
Let us know what you find out.