Hello builders. I made a Tremolo, drive, eq lofi thing for myself. Very happy with it and had fun finding the right circuits and blocks to adapt for my purposes. I would appreciate any useful criticism for improvements.

Two questions.

1) Even with pull down resistors at the front of the circuit (r6/1M) the footswitch pops. Also the EQ toggle pops but i have pull downs at R24 and R40. What am i misunderstanding and how do i fix it?

2) The 3 470n's at C4,5,6 allow the tremolo to work if i use film caps. They measured between 465 and 480n. I tried to make them fit better on the strip board by using ceramic caps. They had a much lower tolerance range
but i measured and found 3 also in the 460-480n range. BUT the tremolo does not tremolo with them. So i squeezed in the film caps but why dont the ceramic caps work here? Curious.





Im including the layout and pictures just in case.

I can't answer the question about the LFO caps. To me, that seems a bit weird. Maybe someone else can give you a reasonable explanation.

I can give you help with this part:

Quote1) Also the EQ toggle pops but i have pull downs at R24 and R40. What am i misunderstanding and how do i fix it?

What you're misunderstanding is DC levels.
If you look at your schematic, when you switch the DPDT, either one or the other 1M resistor is connected to the DC level at the collector of Q1. Suddenly hanging a 1M off that collector to ground is going to change that DC level to some degree, and you'll hear that change as a thump/pop. I'd try either adding a cap between the collector and the first switch, or I'd remove the two 1M resistors, or both. I'd probably try removing the 1Megs first because I like solutions with less parts better than ones with more parts!

One other comment:
What's the purpose of R41/10K? In combination with C16/100n, it's giving you a highpass filter at around 150Hz. That's enough to noticeably steal some bass. Is that the intention?

First of all, wire 3PDT ON-BYPASS switch with IN & OUT grounded (despite pull-down resistors existence)..

Second, C28 (10μF) is floating so potential popping-source when EQ activated..
(ground via 1M EQA switch lug 3..)

As for tremolo caps, ceramic capacitors are somewhat non-linear in their frequency and voltage responses, compared to film capacitors.
Another (IMHO minor) issue with ceramics is that they tend to behave as microphones, thus picking up ambient sound and modulating the voltage across them accordingly.

P.S.
I think C3, C8 and C28 might need rearrangement..

Quote from: ElectricDruid on November 13, 2024, 04:48:12 AMWhat you're misunderstanding is DC levels.
If you look at your schematic, when you switch the DPDT, either one or the other 1M resistor is connected to the DC level at the collector of Q1. Suddenly hanging a 1M off that collector to ground is going to change that DC level to some degree, and you'll hear that change as a thump/pop. I'd try either adding a cap between the collector and the first switch, or I'd remove the two 1M resistors, or both. I'd probably try removing the 1Megs first because I like solutions with less parts better than ones with more parts!

Fantastic. I'm just working on the breadboard before I go crazy digging into all that wiring but..... I deleted r24 and r40. I have a 1M pull down after the 10u/c28. Then I added a 1u after q1 collector and a 1M pull down after it. Seems to have cleared up the popping.

Quote from: ElectricDruid on November 13, 2024, 04:48:12 AMOne other comment:
What's the purpose of R41/10K? In combination with C16/100n, it's giving you a highpass filter at around 150Hz. That's enough to noticeably steal some bass. Is that the intention?

That is the intention. The pedal is supposed to sound like an old radio with a small speaker. Instead of just playing rockabilly and war era jazz it can also sound like the crap radio you could sit around to listen too. The hp filter just gave me a little more of what I was looking for.

Quote from: antonis on November 13, 2024, 05:13:00 AMFirst of all, wire 3PDT ON-BYPASS switch with IN & OUT grounded (despite pull-down resistors existence)..

I switched to In and Out grounding configuration and still popping.

Quote from: antonis on November 13, 2024, 05:13:00 AMSecond, C28 (10μF) is floating so potential popping-source when EQ activated..
(ground via 1M EQA switch lug 3..)

Good call. Thank you. This was key. Thanks for the ceramic explanation too. I'll keep that in mind.

Now I just need to solve this bypass switch.

Quote from: SprinkleSpraycan on November 13, 2024, 02:45:40 PMNow I just need to solve this bypass switch.

If, despite IN-OUT grounded AND pull-down resistors presence, popping persists it should be time to focus on LED popping

Quote from: antonis on November 13, 2024, 03:30:50 PM

Quote from: SprinkleSpraycan on November 13, 2024, 02:45:40 PMNow I just need to solve this bypass switch.

If, despite IN-OUT grounded AND pull-down resistors presence, popping persists it should be time to focus on LED popping

I thought about that. I disconnected the led from the bypass switch and it still popped. Should I do more to rule out the led?

Quote from: SprinkleSpraycan on November 13, 2024, 04:12:11 PMShould I do more to rule out the led?

If you're sure it isn't switch mechanical pop, I'd put the blame on C22..

Try to disconnect R20 (just for testing purpose).. If pop is eliminated, proceed to resistive voltage divider bias for Q1..
(but interchange R38 & R39..)

Quote from: antonis on November 13, 2024, 04:34:36 PM

Quote from: SprinkleSpraycan on November 13, 2024, 04:12:11 PMShould I do more to rule out the led?

If you're sure it isn't switch mechanical pop, I'd put the blame on C22..

Try to disconnect R20 (just for testing purpose).. If pop is eliminated, proceed to resistive voltage divider bias for Q1..
(but interchange R38 & R39..)

I hate when I'm the sole problem. 🥴
I've looked at this layout 100 times but 101 was what was needed apparently. My 1M pdr at the input wasn't actually touching ground. So guess what, no pop now.

Anyways,thanks antonis for the help. Next time I'll double, triple, quadruple check the most obvious thing.