Easyvibe lfo ticking

Started by thomasolsen84, June 09, 2019, 07:02:13 PM

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thomasolsen84

Hi. I built the easyvibe. Pedal is working and has a nice vibe sound but has lfo ticking. Im sorry for newbie questions, I searched on the forum but do not understand where to start to get the ticking away i tried to connect a 100r resistor from the 9v input to the power on the board, but didnt do much difference also i tried to connect a 1000uf from 9v positive to ground but didnt seem to do much either. Im really stuck on this one. I used the John hollis layout to build it. Any help or point in right direction Will be really appreciated.


GibsonGM

Did you insert the 100r resistor, then the 1000uF to ground, or 1 at a time?  I've found they do the trick if you put them on the PCB where the power enters (or up near the pcb if no room).   

Maybe a cap across the power pins of the ICs would help if that's not enough.   I made my 'holy grail'  EV by taking the LFO off the board onto a daughter board and physically separating it from everything.   No more ticking!
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patrick398

Here is a suggestion from Mark Hammer:

strategy 2 is to "decouple" the LFO subcircuit from the power supplied to the audio path.  The traditional approach is to set up a kind of virtual "battery" for the chip providing the LFO.  This can consist of something like a 10uf cap to ground from the V+ pin of that chip, and the insertion of a small-value resistor between the circuit V+ and the V+ pin on the specific chip.  That added cap stores some "backup" charge, such that when the LFO tries to make a square wave, it can pull the current it needs from that cap instead of from the overall power supply.  Think of it like having a slush fund so that you don't have to reach into your savings account or 401K.

The resistor value can't be too big since it would limit the charging up of the cap, and the cap can't be too big since it would take too long to charge up fully.  Generally, for modulation FX, the combination of a 10-100R resistor and 4u7-10uf cap does the trick.

There IS a 3rd strategy for de-ticking, devised by Boss and illustrated on page 2 here: http://moosapotamus.net/files/stompboxology-mo-tremlo.pdf but it involves more modification of the circuit.'

Also beware of long wires travelling across the board, keep wiring short and neat

thomasolsen84

Hi. I placed 100r resistor Just after the 9v input and linked it to the 9v input on the board. The 1000uf cap i put on the lugs of the 9v input Jacks. Might not be the way to do it? I got a picture of my layout. Nevermind the disconected power and ground. Thanks a lot for helping me. How do i go about seperating the lfo to a separate board if thats the way to deal with the ticking. Also i dont know if i should shortsen my wires coming the board to my pots.


GibsonGM

It goes resistor, then the 1000u cap to gnd.    No wire runs should be near the LFO opamps.   If that doesn't work, like I said in my post above and patrick did too - you might have to decouple the LFO chip is its own R and C to gnd at its power pin.

Sometimes you just can't get rid of the tick completely.  That's why I moved the LFO off=board on mine, and if building it again I'd plan to do the same thing!
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thomasolsen84

I took a photo of the way i connected the cap and 100r resistor. Of course i need to do a better job. Just wanted to check if it gets any better. But is this the right connections to make?


thomasolsen84

Thanks a lot for your good help. The way i got it connected with the 100r resistor and the cap isnt doing a lot. Iwill follow your advise and decouple the lfo. Im sorry for asking way too much. I cant seem to get my head around schematics. Any advice and maybe a layout on the daughterboard for the lfo. What parts do i need to move from my existing layout to a daughterboard.
Again you guys are really helpful, helping me with this. I really Im too stupid to get my head around what the circuit dies and what is what on the layout. Way to complicated for me.

thomasolsen84

Im gonna try the cap over the power pins of the ics. Would 10uf be suitable?

GibsonGM

You'll learn, Thomas, not to worry!  I had been building for a long time when I moved the LFO.  I wouldn't go that far right now, it's a little complicated.   On the Hollis pencil drawing, the LFO is all the parts under the ground rail....

I'd be willing to try 10u on the power pins.   Not sure if it'll do very much for you, but it IS a 'tried and true' thing to attempt and is easy to tack on.  You can remove the jumper to the chip pin 4, and replace with a small value resistor too....
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patrick398

Often, when i build tremolos or things with LFOs that could potentially cause ticking i'll have a little power daughter board, with two separate 100R and 220u caps, in a sense you have a 'separate' supply for the LFO and rest of the circuit. Easy enough to whip up on stripboard.

I noticed the layout on Tagboard has incorporated some of these anti-tick methods:
https://tagboardeffects.blogspot.com/search/label/Vibe

Also interesting that it opts for two TL062 as opposed to a single TL064. I'm sure that's significant, but above my pay grade

patrick398


thomasolsen84

I added the two caps to the ics . Its better but not completely free of ticking. Im gonna try to add a daughterboard. Sorry for maybe stupid questions but which
Of the ic is the lfo?

thomasolsen84

Do i remove the 9v input on the layout i used when using this daughterboard? Any other this i need to change?

thomasolsen84

Thanks Patrick :) I thought i had to move one of the ics to separate. Im not entirely sure what lfo is exact. 😃 Just refering to what everybody is calling the ticking i get. 😀

duck_arse

what you want is:

DC socket > resistor > cap to ground

but in your photo you show:

DC socket > cap to ground > resistor

without showing the circuit diagram you are working with, reading the layout seems to suggest that the LFO is part of the IC also doing signal handling.
don't make me draw another line.

patrick398

Quote from: thomasolsen84 on June 10, 2019, 10:32:28 AM
Do i remove the 9v input on the layout i used when using this daughterboard? Any other this i need to change?

So connect the DC socket to the '9v wire' on the daughter board, and the ground lug of the DC socket to the 'GND' wire on the daughterboard. Then you're left with two 9v supplies essentially coming off the daughter board, one goes to the power pin of the LFO, and one to the remaining IC power pin.
Notice on the original layout that both ICs care connected to 9v via long jumpers meaning they are also essentially connected together. You need to separate them, so you could put a cut at K8. Then you'd solder the two 9v wires from the daughter board to either side of the cut.






thomasolsen84

Thanks a lot Patrick 😀 I'll add the daughterboard and see if it fix the ticking. I aldo rearranged the 100r resistor and the cap from 9v input but couldn't hear any difference. Would i want to leave the other mods like the caps across ics and the power cap/resistor and take the wire from there to the daughterboard? Again thank you very much i hope i get to contribute to this forum like you do someday when i get a bit more experienced. 😃

patrick398

Leave the caps across the ICs, it can't hurt. You don't need the cap and resistor from the DC socket now since that is what the daughterboard is doing.
It's possible that this won't work as as far as i can see this layout is using the same IC for the LFO and some of the audio signal. A TL064 is just two TL062 with shared power supply pins, the whole point of this daughterboard is to try and separate the power supply to the LFO IC and the audio IC, since this layout has them sharing one IC already it may not work...but we shall see  :)

You're most welcome. This is a wonderful forum!

garcho

Have you ever lived some place where the shower gets too hot if someone flushes the toilet? Or gets too cold when someone washes the dishes? The ticking you're hearing is a bit like that situation but with current. The low frequency oscillator, the LFO, is going from one extreme of the voltage (say, 9v in this case, or close enough), to the other extreme (0V, again, not really but close enough). When it does that, currents throughout the circuit are affected, like the cold and hot water and the shower. Instead of temperature changes, we have current/voltage changes. Instead of hearing cursing coming out of the shower, we hear ticking come out of the speaker. To fix the hot water problem we need a bigger water heater. To solve the cold water problem we need to rethink our plumbing, how the pipes are connected, how many faucets is one pipe expected to proved water to, do the pipes run outside (could freeze! or in the case of wiring, pick up RFI et al), how long the pipe runs are (a 100' hot water pex loses a lot of heat!), etc. That's a bit like routing throughout the physical actual circuit (as opposed the ideal circuit represented in the schematic). Part of creating a layout for a guitar pedal circuit board is just getting all the connections right in a space that can fit in a reasonable enclosure. But another part, often overlooked, is the routing of the currents, the electrical plumbing if you will.
The suggestions about resistors and caps have to do with giving the pedal a bigger water heater, so when someone washes the dishes, there's still enough hot water for the shower. The combination of the right capacitor and resistor, or adding a cap across the power rails (positive and negative or zero/ground) are there to "hold" (think why we call it a capacitor) electrical charge so when the current goes down during the normal operation of the circuit, the cap "provides" the extra current to keep things steady. The LFO is going to the extremes constantly at the rate you set it at. That causes currents to go to the extremes and enter the audio signal, which ends up sounding like a tick. The suggestions about wiring and routing and length of wire have to do with that phenomenon. Solving LFO ticking usually requires addressing both of those issues.
You're on your way, don't worry! You'll be making DIY super computers in a few years, just stick with it. And do lots of reading. It took me reading the same things over and over to finally be able to conceptualize the basics of electricity, it's an abstract, weird thing.
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thomasolsen84

#19
Thanks a lot you guys for Great answers. Great explenations to make me understand a bit whats going on with this circuit. I now tried the daughterboard mod. But still gets ticking. Its better and for certain i could make my way round the issue. Dont know but maybe this build would be better if i used single/dual op amps instead of the quad ones? Anyway you guys have been much helpful. Allthough i didnt fix the issue at least i learned a lot from you guys. So i guess Thats Worth a lot more than a noise free pedal. I really think this diy pedal stuff is regarding and om gonna keep trying. And hopefully i learn enough to help other with their issues someday.