Hummmm

[garbanzo]

My Helix rack works fine as far as I can tell. However when I connect to my pc via usb I get a low grade hummmmmm. I am updated to 2.54 software and am in an environment without florescent lighting, or ever other equipment other than pc, Helix and my amp GK MB200. I am presently in an out building with no other electrical things connected to the circuit, and I have the same problem at home where there are other electrical things connected. So the problem is the same in both settings. Does anyone have a suggestion to offer, or have similar experience?

Best wishes garbanzo

[soundog]

Tried different USB cables? Any change when wiggling the connector on either end? Any change when you touch metal on PC or Helix?

[garbanzo]

Thanks for the thought soundog, but no. I have thried that and changed cables too, but to no avail.

[jbuhajla]

When you run your laptop off battery power (not computer power supply) do you still get the hum?

[PerS]

I guess you have a portable computer/laptop running on batteries but you have a charger connected..? And I understand it’s only when you have the computer connected to your Helix you get the hum. No hum without computer or the Helix connected to something else, like a powered speaker or into a mixer.

You are also connected to the same socket/plugged into the same extension cord. Not two different sockets/outlets.

If so, try

·         Disconnect your charger from your laptop and see if the hum goes away

·         Try your Helix with another computer

Have been into this myself but in my case,  it was a fluorescent light, a lamp with a halogen lamp and a noisy transformer, a ground loop… at the same time.  Solution was to safe the grounding between ALL the units, unplug the lights (the halogen was hardest to find as even if I turned the light off the transformer was on). The one that killed the last bit of hum was an insolation transformer (from Lehle) between my pedal board an my POD HD Pro (my rig at the time and if I take the transformer out now I get the noise back on the Helix too).

Don’t now it help but maybe a lead… To give a better answer it would help to know how your gear are connected together. I guess its more then the Helix rack and your computer.

[PerS]

Sorry jbuhajla, did not see your responce :-) But we are on the same track...

 

//Per

[garbanzo]

 

Thanks for your input PerS and jbuhajla! I have just tried disconnecting my laptop from the Helix usb and disconnecting the charger with no changes in the hum.

 

 Sound wise my Helix connects to my amp (a Gallien Krueger MB200 which is a class D head ) and uses the aux in to the amp so as to avoid amp colouration of the sound as far as possible, and of course this connects to the speaker cab, and finally the Helix is connected to my laptop. 

 

Let me explain my electrical circuit set up, I have one extension cord with multiple outlets on it. It is a grounded circuit. Electrically Helix, amp and laptop are all connected to the same extension cord using the cables that came with respective devise. I have experimented with changing the usb cable with no results. The electrical outlet I am connected to is grounded and there is nothing else connected on the circuit, nor on the fuse box. At present I am at my summer house outside of Stockholm, but I have the same problem at home where there are considerably more devises connected to the electronic at home. Still same low grade Hmmm.

 

This baffles me. Please weigh in if any ideas pop up.

 

Thanks garbanzo

 

 

Hej PerS  Glad Midsommar!

[Rewolf48]

If it remains after disconnecting USB then you have eliminated that as a primary cause. 

 

Are you running any audio cables close to any power cables and especially transformers? A poorly shielded or ungrounded cable can allow mains hum to be induced. Try starting from the absolute minimum and add things one at a time listening carefully. When you start to hear hum then you have found a contribution but not necessarily only cause 

 

start with just the amp and cab 

then patch Helix in

then plug in helix power 

then switch on helix to an empty patch

then plug in guitar - vary guitar volume and play 

then use a patch with amp

then plug in usb... etc

 

Also consider gain staging... the Helix volume should be as high as practical as a low level Helix out boosted at the amp only will magnify any induced hum. And another thing when you add the guitar is to look at the noise gate setting on the input.

Final thing from back in the days when I ran a rack system is that sometimes you can get a ground loop between the rack and cases of the units.. if this is the case you can try patch cables with lifted ground or hum eliminating plugs (with isolation transformer)

 

[jbuhajla]

Also check if the hum goes away with no instrument plugged into the guitar input. 

[PerS]

Hej garbanzo

Va roligt, tror det första gången det blir svenska här... 

Eftersom du har brum även utan PC'n ansluten så är nog de två senaste tipsen vägen att fortsätta. Kan bara tillägga att undvika härvor av kablar, speciellt med både el och signalkablar. Samt att när du kopplar loss allt och kopplar samman, ha utrustningen avstängd. Jag blåste en USB-port pga att jorden inte funkade mellan min mixer och min gamla POD XT... Dvs alla ändringar görs med strömmen avstängd.

Oavsett så borde det funka. Kikade på förstärkaren och ser inget konstigt. En enkel test - Du kan ju prova en EQ i slutet av signalkedjan, t.ex. Lo Cut/Hi Cut, och ställa LoCut på t.ex. 110 Hz. Det du hör borde vara 50 eller 100 Hz. Bara som en test för satt se om det kommer signalvägen eller ej. 

 

Sorry guys, my bad... couldn't resist to comunicate in swedish for the first time on this forum (been here since POD 1.0). If curious, Google translate :-) 

 

Chears //Per

[garbanzo]

Hej Per!

Ja, kul med lite svenska, jag har inte uppfattat att vi översvämmar forumet direkt. Jag är på resande fot för tillfället och har inte kunnat testa förslagen ovan men jag ville tacka för din input!

[garbanzo]

Hi guys

 i wanted to get back and say that I am travelling at the moment and have not had time/opportunity to test any of the good and logical suggestions I have received. I will get back with a progress rapport. I know it is very unsatisfying to engage in trying to solve someone else's difficulties and then not hear anything. Will get back soon.

Thanks

garbanzo

[garbanzo]

Hi guys!

I have now had the opportunity of checking things more systematically. My Hmmm arises when  pc, helix, head and guitar are connected and then I connect the power to charge the pc/laptop So it appears that the culprit is the pc charger. I take full credit for having missed this earlier! What do I do so as to eliminate that as an interference? Any suggestions?

 

Vad säger PerS? Känner du till en lösning som man hittar här hemma? Kjell&co? Någon sorts filter? Sånt här förstår jag mig inte på?

 

Best regards

 

garbanzo

[jbuhajla]

1 hour ago, garbanzo said:

Hi guys!

I have now had the opportunity of checking things more systematically. My Hmmm arises when  pc, helix, head and guitar are connected and then I connect the power to charge the pc/laptop So it appears that the culprit is the pc charger. I take full credit for having missed this earlier! What do I do so as to eliminate that as an interference? Any suggestions?

 

Vad säger PerS? Känner du till en lösning som man hittar här hemma? Kjell&co? Någon sorts filter? Sånt här förstår jag mig inte på?

 

Best regards

 

garbanzo

I haven't found a solution for that issue yet. I just make sure my laptop is fully charged for extended times of use, and charge it again after I am done with my audio tasks with Helix. 

[HonestOpinion]

4 hours ago, garbanzo said:

Hi guys!

I have now had the opportunity of checking things more systematically. My Hmmm arises when  pc, helix, head and guitar are connected and then I connect the power to charge the pc/laptop So it appears that the culprit is the pc charger. I take full credit for having missed this earlier! What do I do so as to eliminate that as an interference? Any suggestions?

 

Vad säger PerS? Känner du till en lösning som man hittar här hemma? Kjell&co? Någon sorts filter? Sånt här förstår jag mig inte på?

 

Best regards

 

garbanzo

 

You probably already tried this but the easiest solution might just be to put the laptop charger and the Helix on different and ideally separately fused outlets if possible. Aside from solutions like the Lehle isolation transformer proposed above by Pers it might also be worth trying a replacement laptop charger from Amazon. They can be had relatively cheaply these days.

[soundog]

Try removing the ground from the laptop charger: use a three prong female to two prong male adapter (or similar for your country). Or plug your laptop into a power conditioner thats plugged into a separate ac circuit. Get the danged thing out of here.

[dotpc]

You may want to look into a Tripp Lite Isobar. Solved some strange noise issues for me.

[garbanzo]

PerS

 

Could you explain what you mean by,

 

" Solution was to safe the grounding between ALL the units "

 

At the moment I have all plugged into the same wall socket which itself is grounded. All units have grounded cords ei Helix, pc´n, and amp head. I thought that this arrangement in itself is grounded, I just want to be sure that I am not missing something.

 

The last thing you did when you had similar problem was to use a isolation transformer (from Lehle). Where did you purchase this? I would have written this in Swedish but I thought that it would exclude too many others who may benefit from the exchange.

 

Best

 

garbanzo

[PerS]

Sorry for late reply...

 

The problem I run into when was that the grounding between the units was through the shield of the audio cables. As my power sockets was not grounded and was using two different sockets, this resulted in two  potentialdifferent depending in what extension cord the unites where plugged in to. This current was even out through the shield in the audio cables. So when I was trouble shooting I unplugged all audio cables. Stared the power amp no noise. Added the mixer, no noise. My mistake now was  to add the usb cable from the computer connected to the other socket... I saw the sparc between the cable and my XT. The usb was gone. If i would have added the audio cable from the XT to the mixer I would've been ok. 

So the solution in my case was those things

* I made a grounding of the two different extensions so all equipment was on same level. I also extended the grounding to a real grounding point. My rack+pedal board and my pc.

* I rearranged all cabling in my rack. Power on one side and signals on the other side.

* Added a power conditioner, Furman, taking care of all power in rack and two my pedal board.

* Disconnected one fluorescent lamp and one halogen lamp with noisy transformer.

 

Still had some hummm so the solution  was the Lehle transformer in audio cable  between my pedal board and rack. All dead quiet...

 

Today I have a smaller pedalboard, Pedal train Nano, with my Shure tuner, Variax power, BD2, Echoplex boost and Lehle transformer. 

Signal chain is  Guitar -> A/B/Y -> tuner/pedal chain -> Lehle transformer -> Helix -> Mixer (sampson rack type) -> Power amp (InterM 500) -> Speakers (modded hifi tuned for guitar, more like pa speakers, homemade :-).

If I remove the Lehle I get back the hummmm.

 

The Lehle transformer is this - https://moodysounds.com/produkt/p-split-kit/. I bought the transformer, the kit didn't exist then, but it's the same. 

 

Conclution is - All attached units at the same ground level, should not even out in the audio cables. Break the chain with a transformer.

 

In your case I would try a different pc in the first step. The Lehle transformer can be handy anyway, but will probably not help if the charger or pc inject hum.

 

And now sorry for a long reply :-)

 

Chears /Per

[ColonelForbin]

Probably try putting an ISO between Helix and amp. Like, an Ebtech or similar. You could use an AB/Y and use the isolated B output too. Or something like the Empress stereo buffer thing.

 

Cheapest option; get the Behringer or similar knock off of the Ebtech. Run Helix to Ebtech; Ebtech to amp.

 

Cheap:

https://www.sweetwater.com/store/detail/HD400--behringer-microhd-hd400-2-channel-hum-destroyer

 

Ebtech:

https://www.sweetwater.com/store/detail/Hum--ebtech-he-2-2-channel-stereo-hum-eliminator

 

Spendy:

https://empresseffects.com/products/buffer-stereo

 

https://www.sweetwater.com/store/detail/LittleDual--lehle-little-dual-amp-switcher

 

https://www.sweetwater.com/store/detail/TruePathABYWh--fulltone-custom-shop-true-path-aby-st-white