Weird "hum" from a couple of pedals

[Kost1978]

Hi guys,
I'm a slow builder and built around 30 pedals in 2/3 years of activity and I've never experienced this "problem" beside the following examples.

I have a dual OD with a Rockett Animal in one side and a Zendrive in the other, when I use the Zendrive side I hear a cyclic hum coming from my amp when I'm not playing (with any level of volume selected). Same thing happen with the SHO, but only if it's cranked, so it's not really noticable in a normal situation.
Both circuits works quite well to my ears (I built several SHO, all of them with the same "issue"), I don't have any other problem to report.

I'm quite sure it's not my power supply, cause I have several of them and the hum it's obviously louder with the cheaper ones, but still present even with the quiter power supplies I have (while the othe pedals are always dead silent, no matter which power supply I use).

I guess this hum is some sort of "radio frequency" I heard about in some pages of this forum, am I right? Or, are there any other kind of hums around? is there a way to cure it?

Thanks!

[Neil mcNasty]

There is almost allways some ripples in the current, even when using the "best" power-supplies.
I use this Extended version of the Huminator which I drew up lately (updated & correct version):


I also use my "Dying Battey Simulator" that you'll find info on here:
http://www.beavisaudio.com/projects/DBS/
Since I do not use it as a "Sag" control on any pedal, I put it between one of the power supplies and some pedals, and I dial it just slightly down (probably just 1/8 of a volt) and that removes alot of noise issues coming from the cheap supply.

Another noise issue I've come across, is when using old buffered EHX pedals, like The Octave Multiplexer, there is a ticking like bleedtrough that is audable when putting it in front of dirt pedals, even when everything is bypassed.
Lesson being that the effect order/the way we hook up pedals, can make combinations of signal that results in noise issues.
This sometimes also happens with the Green Ringer sometimes... With one specific setup you'll get something that sounds like a carrier frequency bleedtrough even when all pedals are in bypass, but with other setups, you don't...
This sometimes happens even when you have all True Bypass pedals down the line, and not just when there is a Buffered pedal involved like in the previous case with the EHX.
A sometimes strange phenomena, which I suspect is all about power supply and filtering quality, since adding the Huminator or a Voltage Divider like the Dying Battery thingy solves any noise issue 99% of the time...

Try the Huminator, it's a wonderfull tool to have, no matter how good your power supply is supposed to be...

[nocentelli]

Are you sure about that circuit and layouts? They appear to have a diode pointing from power to ground. I've seen reverse polarity protection diodes pointing the opposite way, but yours appears to short +9v to ground, I'm confused.

[Neil mcNasty]

It's a Half-Wave Rectifier not Polarity Protection.
And you are correct, that diode is the wrong way around...
Thanks for noticing... I drew it up after I built mine from a different layout. Sorry!
The above layout has now been updated and should be correct...

[Kost1978]

Thanks for the suggestion Neil, your circuit is easy enough to give it a try very quickly.
As soon as I'll have some free time I'll build it and let you know!
Thanks.

[ξεναγος νεκροπολης]

hi there!

i have a similar problem
i know that some effects just don't work together, but these days i'm building for a bass player a civil war big muff and an mxr custom badass modified o.d. in the same box.both effects work great on their own, but when i turn both on and don't play anything, i get a very annoying noise.when i hit the strings, noise stops, but after the sound fades out, noise comes back.
something like Kost1978 described above..

is this a common supply problem?

would huminatorII that neil posted work for my problem?
thanks
Savvas

[Kost1978]

Hi Savvas,
as soon as I get some free time I'll build the Huminator and report back if it's working for my problem.
I'm not sure when I'll be able to build it though...
The Huminator looks like a super easy build, if you have the time and parts try to build it before me!
Thanks!

[ξεναγος νεκροπολης]

hey mate!
i've alredy build it.
it's great.
just go for it. it worked perfect for me.
i was about to add a 100r in series with the supply, when i saw this threat and Neil's board. i asked first but then i thought why not try it right away!
thanks Neil! this one is a must in this kind of builds!

[Kost1978]

Thanks for the feedback!
I'm going to try it as soon as I can!

Have a nice day.

[Neil mcNasty]

Great to see that the Huminator II worked out and solved your problem ξεναγος νεκροπολης!
Hope it solves yours as well Kost1978.

Ironic that I am now experiencing similar issues with my latest combo pedal of GE Fuzzrite and The JBF Bonamassa Fuzz, the ironic thing being; that I forgot to add this handy tool at the same time as I'm telling friends about how great it is and how it always should be added in these cases...

I thought I'd share the videos from DIY Guitar Pedals, where I adapted the layout from.
Hopefully it will become handy if someone else is having the same issues with their build in the future:
https://www.youtube.com/watch?v=bv54-vZnqv8
https://www.youtube.com/watch?v=julbbj4R3Ko

Since there are many of us that combine 2 effects in one enclosure, I also drew up a tiny layout specially for Dual Effects Builds as well:

[Kost1978]

Hi Neil,
sorry for the late reply, but I didn't find some time to build the Huminator since a couple of days ago...
Indeed it solved my problem as well, actually it works great even in some noisier pedals I have (DAM Meathead for instance).
So, thanks a lot for your suggestion, I'll also try to add the Dual Hum directly to the double pedal which was giving me troubles.

Have a nice weekend!
Paolo.

[Zanius]

Hello everybody! Currently thinking of making a power supply, saw the Power Brick on the forum, but I don't really need other voltages or different polarities (for now). So I was thinking of doing something simpler when I saw this.



So, if I just box that second vero (with multiple outputs) and power it with a regular supply of say 500mA, I get myself a hum-free power supply? It seems right, but I thought I ask before I spend time and resources for no reason :)  Also, if I expand the vero keeping the same res/cap pattern can I get 6 outputs?

[Addy Bart]

Thanks Neil for the Huminator vero. It works a treat. Even used it to sort out the whine on a commercial pedal.

Just a quick question about the diodes: would another type work here? I've got plenty of 1n4001 but not many 1n5817 left.