Univibe noise, help!

[Calamardo]

Hello! I just finished my univibe clone, and its sound amazing (yeah! worked at first try). But i have a noise issue, a background noise that i think is the lfo filtered in the audio signal. Even if i turn the guitar volume to 0. Any ideas to fix it are welcome. Thanks

[RedHouse]

Hello! I just finished my univibe clone, and its sound amazing (yeah! worked at first try). But i have a noise issue, a background noise that i think is the lfo filtered in the audio signal. Even if i turn the guitar volume to 0. Any ideas to fix it are welcome. Thanks

A univibe will have noise that sounds like it's still 'vibing' when the guitar is turned to zero (cause it is) it's just the nature of the beast.

[Calamardo]

Thanks for reply!. I know "univibes" can have a little background noise, but in mine the noise is loud. Sometimes i just cant play clean

[snoof]

make sure you test it with nothing plugged in to the input of the pedal.  that will narrow your debug.

[Calamardo]

How? with the amp on,vibe plugged and without the guitar plugged?. What should happen?

[Calamardo]

bump

[R.G.]

There are many types of noise. What does your noise sound like?

[Calamardo]

Thanks all for reply. Is a constant background noise (like motorboating), not pop, that change only if i move the speed pot and not desapear if i turn the guitar volume to zero.
My first thought was: a bad ground, but all ground wire are fine. Second thought:power supply, im using a 12vcd wall wart that i measured and i have about 19vdc so i think is fine, changed the transformer and nothing:the noise is there.
By the way: I used a pcb transfer that is not Neovibe cause the pdf file have poor resolution. Im thinking, if i cant fix the noise problem use a better resolution pdf file that i saw resently, and remake the pcb now with Neovibe layout. Have the neovibe any noise issue?.

[R.G.]

OK, if it's a motorboating kind of sound, and if the frequency changes when you change the LFO speed pot, then that is very different from the hiss or hum problems mentioned earlier.

The word "noise" in English is very much like the word "weed". There is no plant that is a weed all by itself. But every plant can be a weed if it's growing where you don't want it to grow.  Likewise, "noise" means "any signal that you don't want to be present; so it's important to distinguish between the three main types of noise:
1. thermal and flicker noise, which is always hissing or crackling.
2. Power line noise, a low growl or hum that is unchanging in frequency
3. Some other signal either received (RF pickup) or internally generated (oscillation or bleedthrough).

These all have very different causes.

In your case, yes, it is possible that the layout is causing the problem. It is also possible that there is a problem with your soldering or component values that is letting the LFO bleed through to the signal path. We might be able to help you if you posted the layout that you did use.

The Neovibe is - I think! - the single oldest and best tested of any effect clone board on the internet. It does not have any noise issues when built properly.

[Calamardo]

Ok,thanks again R.G.!. I'll try the Neovibe, and see what happend. The layout that i used is from this site:
http://www.harpamps.com/schematics/
http://www.harpamps.com/schematics/unvbachk.pdf
Is pretty much the same as the Neovibe

[Calamardo]

The shield of the enclosure can help with the motorboating? I tested the beast without it...

[R.G.]

Ok,thanks again R.G.!. I'll try the Neovibe, and see what happend. The layout that i used is from this site:
http://www.harpamps.com/schematics/
http://www.harpamps.com/schematics/unvbachk.pdf
Is pretty much the same as the Neovibe

Web site at harpamps says

I found an old archive of 86 effects circuits all in PS format. I have converted them to Adobe PDF files to make them easier to read. I know very little about effects building, but some of these look very simple and may be easy to build.

Like they were in a tin can dug up in the back yard. That archive was the first batch of effects clone circuits from Leper's archive, where Jamie Heilman and I stored effects in the early days.

Just changing to the Neovibe won't help much. That's a very old version of the Neovibe. I laid that one out in the mid 90's. It's about eight versions back. On the other hand, there's nothing much wrong with it, either. It has no noise problems; only size and positioning issues. It worked fine.

So your problem is with the building and soldering itself.

I think that you should check to be sure your power supply is correct.

Go read "Debugging Thread: What to do when it doesn't work" and follow those instructions.

[snoof]

How? with the amp on,vibe plugged and without the guitar plugged?. What should happen?

I was just suggesting that you test it this way to make sure that your noise was coming from the pedal, and not something connected to it.  yes, amp on, neovibe output to amp in, nothing plugged into the input of the univibe.  If the noise had gone away, you would know that the prob was with whatever was plugged in to the univibe.

[Calamardo]

Me again!. So i redone my Univibe with new components and the pcb of Neovibe. I hate to say that have the same behavior of my previous try. At this point, i switched my power supply (19 vdc cheap wall wart) to two 9v batteries in series and i have to say that the "hum" part of the noise was gone but basicaly the noise is still there. This week i'll make the enclosure and see what happend.

[R.G.]

It's very important to know what the noise sounds like.

Hiss?
Crackling?
Angry hiss?
Radio stations?
Thumping?
Hum?
Buzz?

Those all have different causes.

If it's still motorboating once the power supply hum is gone, you likely have a wiring problem.

[Calamardo]

Hi RG! The noise sounds like this:

http://www.yourfilehost.com/media.php?cat=audio&file=uninoise.mp3
http://www.yourfilehost.com/media.php?cat=audio&file=uninoise_01.mp3

I recorded the files direct to my pc, i think that through my amp the noise is more loud.

[snoof]

I don't really hear anything wrong??  The clip with the gtr sounds fine to me.  The univibes will make some noise when you're not playing anyhting through the amp.  Is it in an enclosure??  If not it might pick up RF type noises.

[Calamardo]

The noise of the first sample is really loud through my amp and no is not in an enclosure so i will try to put it