Crying time non madbean ( fixed sort of)

[RobA]

I still haven't been able to get this to tick. I'm building a new variable power supply in the next couple of days though. That should give me a better opportunity to test the voltage theory.

Anyone have info on what op amps were used in designs like this one that do exhibit ticks and thunks?

[Matt]

I still haven't been able to get this to tick. I'm building a new variable power supply in the next couple of days though. That should give me a better opportunity to test the voltage theory.

Anyone have info on what op amps were used in designs like this one that do exhibit ticks and thunks?

Thanks for your time and help.  I haven't looked at this thread since your post on the 6th.
Just got back in town or else I would have replied sooner.

Here's a list of what I used.  Ne5532 for the audio opamp, a lm358 for the lfo section, vtl5c1 for the vactrol, 2n3904 transistor.  High brightness red led for rate indicator. 

I did notice that the filter cap for the lfo on my layout is an inch away from the opamp.  Maybe that's the problem?

[RobA]

I still had the circuit on my breadboard. I'm keeping it until I have my new power supply finished so I can test it with a continuous voltage range to see if there is a point that'll cause the ticking. So, I put your parts list in there -- no ticking.

I don't have any super-bright red LED's though. I tried with a bright water clear red. This didn't get any ticking.

I'd think the LM358 was a perfect choice for the LFO op amp. The 5532 sounds good, but there is one thing about it that could be related. I've noticed that it draws a pretty large amount of current. This is especially true if an unused op amp isn't terminated. I'd check to make sure that the second side is terminated correctly. Although, I did try on my test board to leave it unterminated and I didn't get ticking.

I doubt if it is the filter cap. I tried moving mine all the way down my breadboard and got no difference. I even tried just taking it out and I got no ticking.

There are two things I've changed that do seem to bring it closer to ticking (closer in that the sweep does seem to bottom out harder); Moving the LED to a brighter variety and moving the cap that goes from pin 3 to ground on the audio op amp to a smaller value.

Two things that might help me get closer to your setup is if you could give me the forward voltage drop of your LED and the voltage at the power input to the board.

[Matt]

I still had the circuit on my breadboard. I'm keeping it until I have my new power supply finished so I can test it with a continuous voltage range to see if there is a point that'll cause the ticking. So, I put your parts list in there -- no ticking.

I don't have any super-bright red LED's though. I tried with a bright water clear red. This didn't get any ticking.

I'd think the LM358 was a perfect choice for the LFO op amp. The 5532 sounds good, but there is one thing about it that could be related. I've noticed that it draws a pretty large amount of current. This is especially true if an unused op amp isn't terminated. I'd check to make sure that the second side is terminated correctly. Although, I did try on my test board to leave it unterminated and I didn't get ticking.

I doubt if it is the filter cap. I tried moving mine all the way down my breadboard and got no difference. I even tried just taking it out and I got no ticking.

There are two things I've changed that do seem to bring it closer to ticking (closer in that the sweep does seem to bottom out harder); Moving the LED to a brighter variety and moving the cap that goes from pin 3 to ground on the audio op amp to a smaller value.

Two things that might help me get closer to your setup is if you could give me the forward voltage drop of your LED and the voltage at the power input to the board.

Dumb noob question, how do I find the forward voltage drop?

[midwayfair]

Use your multimeter's diode setting. It's also the continuity tester.

[Matt]

Use your multimeter's diode setting. It's also the continuity tester.

I knew it was a dumb noob question.  I wasn't thinking.  led = diode.  

Anyway, I measured the led in the circuit, 1.9v.  I have a few LEDs laying around and they measured 1.57 - 1.6v.  I measured the voltage at the DC jack at 9.62v.  After the 100ohm CLR, it read 9.18v.

I'd think the LM358 was a perfect choice for the LFO op amp. The 5532 sounds good, but there is one thing about it that could be related. I've noticed that it draws a pretty large amount of current. This is especially true if an unused op amp isn't terminated. I'd check to make sure that the second side is terminated correctly. Although, I did try on my test board to leave it unterminated and I didn't get ticking.

I doubt if it is the filter cap. I tried moving mine all the way down my breadboard and got no difference. I even tried just taking it out and I got no ticking.

There are two things I've changed that do seem to bring it closer to ticking (closer in that the sweep does seem to bottom out harder); Moving the LED to a brighter variety and moving the cap that goes from pin 3 to ground on the audio op amp to a smaller value.

Two things that might help me get closer to your setup is if you could give me the forward voltage drop of your LED and the voltage at the power input to the board.

Yeah I went with the lm358 after some reading about lfo ticking.  Didn't help but it worked so I left it.  I tried a 4558 in place of the ne5532 just to see but it made no difference.  I checked the cap you refered to, I have a 1uf tantalum there.

Again, I appreciate both of you helping me with this.  It's a very cool pedal and can't wait to get it working right!

[RobA]

Thanks for those numbers. My multimeter actually can't read LED forward voltages for LED's that are higher than about 1.6V. So, I usually just hook them up with a series resistor and measure the voltage across the two leads of the LED.

The tantalum cap is a difference from my circuit. I've got an electrolytic in there. It's not likely to be the cause, but I'll find a tantalum cap to try.

The LED I have in the circuit now is around 1.6V. I'll see if I can find an LED that matches fairly closely to yours.

Your circuit looks to be drawing more current in the LFO than mine, not a lot more but about double. I wonder if that could be part of the problem and I wonder why. So we can get a better idea of where they are at, can you measure the voltage directly across the resistor? Turn the LFO rate to max for the measurement.

I'll let you know what I see when I put the tantalum and different LED in.

[Matt]

The resistor measures .46v.

Quick question on the led, will it give me a false reading since its connected to the circuit?

[RobA]

I think it will be fine. It doesn't have anything in parallel and you are measuring directly across LED.

The voltage across the resistor in mine is 2.8V. So, that could be pointing to something. I'll measure it again when I get a better match for an LED in there.

Any chance we can get a photo of the actual circuit?

[Matt]

I'll have a chance to unbox it Sunday.  I'll post it then.  Thanks!

[Matt]

Under promise and over deliver.  Hopefully that shows you what you need.  Let me know if I need to zoom in on anything.

[RobA]

Under promise and over deliver.  Hopefully that shows you what you need.  Let me know if I need to zoom in on anything.

Cool, thanks. I'll compare to mine and see if I can get any clues.

[Matt]

Under promise and over deliver.  Hopefully that shows you what you need.  Let me know if I need to zoom in on anything.

Cool, thanks. I'll compare to mine and see if I can get any clues.

Also, If I get a chance, I'll pick up a different power supply today and see if that makes a difference.  I have 2 but they are both Boss psa120.

[RobA]

It couldn't hurt to check with a different power supply. But, I'd think that Boss has plenty of current available.

I went through your photos to see if I could see anything obvious that we have different. I couldn't see anything. But, some spots are hard to trace in the photo. Do you have a link to the schematic you worked from?

[ch1naski]

You guys tried just using a battery? If there's no tick when using a battery, you're at least narrowing it down to the power supply. just a thought....

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