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Lkdog

4CM noise elimination and signal chain tips?

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Am using the 4CM Template that came with the Helix to use with my Carol Ann (CA) Triptik

 

For hum/hiss reduction I have done the following:

 

1) The 1/4 Out heading to the CA Return is set to Instrument instead of LINE.

2) I have a EBTECH Hum Eliminator box with the IN/OUT cables to the CA AMP Return which gets rid of most of the ground loop hum. (The EBTECH thing pictured below really works)

3) I stuck a Noise Gate after the SEND/Return block. (Have it set at 71db Threshold and 500ms Decay)

4) The Noise Gate in front at INPUT is OFF

5) Volume on the HELIX is all the way up.

6) The SEND/RECEIVE output/input Block on HELIX  is set to LINE.

 

Everything else is at default.

 

 

It is working and sounding pretty good with not a lot of tone suck with the Noise Gate.

 

Am I missing anything?

 

150562000000000-00-500x500.jpg

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Exactly my problem with the Marshall JVM410H, even if I still have no idea, whether the reason for the hum is the same one as in your case. I am using 2 noise gates in the signal chain, one at the input (general settings) and one in the S/R path of the amp, but with much lower treshold (about 20) on the second one. I got something close to silence now but at the prize that now I can forget dynamic playing :-(. With your solution that should be still possible. I'm going to test it right away ... Thanks so far for sharing your experiences!!

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I run 4cm on a road king, PRS Custom 50 and a TC50.

 

-I have my ebtech hum eliminator also sitting between the send on the helix and the input on the amp.

 

-Send/return set to instrument level.

 

-make sure effect loop is set to unity

 

-input gate on, no gate after loop block

 

-no volume control on 1/4 out. In global settings

 

-does it hum when there is no guitar plugged in?

 

-does it hum when no guitar and no usb plugged in?

 

- Are you using the helix to change channels on the amp? What are your connections?

 

- Are you using any sort of power conditioning/protection/etc?

 

Another tip. If you split the chain after the loop block you will notice a volume increase. Setting level on the output/merge block to -3db will solve this as that is the amount added by splitting the signal.

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I last used the 4CM with my Boss GT-10B and an Ashdown head, so I can't say much about Marshalls and such. But a few general things:

 

1. Does setting the Send on the Helix to Line level cause the Return of the head to be overdriven? If not, or if you can adjust the Retun gain, I would try setting the Send to Line level as that should provide a bettee Signal-to-Noise ratio.

2. How long are your cables? Asymmetric connections like guitar amp send/returns will always pick up a lot of noise, and it gets worse over distance.

3. If you have two passive DI boxes, try to use them to form a symmetric (XLR) connection between the Helix and the Amp. Passive DIs also work in reverse, so you can use them on either end to turn 1/4" into XLR and vice versa.

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Exactly my problem with the Marshall JVM410H, even if I still have no idea, whether the reason for the hum is the same one as in your case. I am using 2 noise gates in the signal chain, one at the input (general settings) and one in the S/R path of the amp, but with much lower treshold (about 20) on the second one. I got something close to silence now but at the prize that now I can forget dynamic playing :-(. With your solution that should be still possible. I'm going to test it right away ... Thanks so far for sharing your experiences!!

 

 

I think Ground loop hum (which is different than noise floor hiss) is hard to track down in any environment.

You might try one of these EBTEChs.

There is another company that sells cheaper cost ones that is supposed to also be an isolation transformer and do the same thing (PYLE).

PHE400.jpg

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I run 4cm on a road king, PRS Custom 50 and a TC50.

 

-I have my ebtech hum eliminator also sitting between the send on the helix and the input on the amp.

 

-Send/return set to instrument level.

 

-make sure effect loop is set to unity

 

-input gate on, no gate after loop block

 

-no volume control on 1/4 out. In global settings

 

-does it hum when there is no guitar plugged in?

 

-does it hum when no guitar and no usb plugged in?

 

- Are you using the helix to change channels on the amp? What are your connections?

 

- Are you using any sort of power conditioning/protection/etc?

 

Another tip. If you split the chain after the loop block you will notice a volume increase. Setting level on the output/merge block to -3db will solve this as that is the amount added by splitting the signal.

 

 

Thanks for the info.

I will try The Noise Gate at front of chain vs after the Send/Return block to see if there is a difference in how it works.

In response to whether the hum is there with no guitar plugged in- yes.

The hum is separate from any Hiss/Noise floor issues when gain is applied so am pretty convinced it is a ground loop issue.

 

I guess now I am just trying to address noise floor/hiss when gain is higher and make sure I am not doing anything that contributes ot it.

It is near totally silent on the clean channel of the CA Triptik..

 

In general- there is a lot going on in basement studio.

I actually get a slight hum on the HELIX (and AXE FX II) played standalone on my electrical circuit.

I think it may have to do with my Coax internet/TV cable being on the same circuit (in two places) in the basement connected to my home theater and router and computer.

 

One thing i might test is to disconnect the Coax cable from this circuit to see if that eliminates the hum.

 

Anyway- it looks like I am on the right track. I will check the other settings you mentioned.

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Line level vs Instrument/mic: Most amplifiers are expecting to receive instrument level. It's also the easiest way to achieve unity gain. On my Road King, for example, unity is @ 12 o'clock. If I were to send it a line level I would have to compensate for that on the amp. With no detailed markings on this knob that would be extremely difficult to achieve.

 

Regarding power: you may be able to try an iso brick. Can't remember the company that makes a lot of them... but I can tell you they're white. Lol. Maybe use that to separate everything in your basement. Florescent bulbs can also cause noise if you have any.

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Line level vs Instrument/mic: Most amplifiers are expecting to receive instrument level. It's also the easiest way to achieve unity gain. On my Road King, for example, unity is @ 12 o'clock. If I were to send it a line level I would have to compensate for that on the amp. With no detailed markings on this knob that would be extremely difficult to achieve.

 

Regarding power: you may be able to try an iso brick. Can't remember the company that makes a lot of them... but I can tell you they're white. Lol. Maybe use that to separate everything in your basement. Florescent bulbs can also cause noise if you have any.

 

 

I have so much crap running in here... LOL.

 

I used one of these to eliminate the hum from the Coax going into my Home Theatre/Stereo rig.

Dead quiet on that end of equipment room  now. Maybe I need to try one on this end of studio as there are two separate COAX feeds coming in here.

It's an ongoing battle..... :)

 

holland_cisp_hr__35400.1450403250.500.50

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The only thing you are missing is for Peter Hamm to show up and criticize you for not using the Helix Amp Blocks instead.

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One thing i might test is to disconnect the Coax cable from this circuit to see if that eliminates the hum.

Keep in mind that it could not just be the coax, but anything else that connects to a different earth / ground pane. Sadly ground loop removal is a very tedious procedure.

 

Aside from that, I'd like to leave an opinion: Power conditioners will not help here. An overvoltage / transient protection is very useful, even more important is something that tells you whether you have good earth etc. Some also contain hamonics filter that make sure your attached devices will only get a more or less pure 50/60 Hz sine and no "dirt", e.g. from fluorescent lamps.

I already doubt the Helix would be affected by that though as it has a switch mode power supply - there is almost no way that harmonics from the power line can couple into the DC side of it. So how should it help against hum that not only occurs much deeper down in the circuit, but also in conjunction with another device? Plus, if the hum is at 50/60 Hz, it's not a harmonic, so no filter could ever get that out of the Helix' or the amp head's power.

 

I'm curious to hear whether a power conditioner helped anyone get rid of a ground loop. Until then, I'd like to be the counterweight for those who keep recommending them for all kinds of issues, from noise over hum to tube eating Marshalls.

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Keep in mind that it could not just be the coax, but anything else that connects to a different earth / ground pane. Sadly ground loop removal is a very tedious procedure.

 

Aside from that, I'd like to leave an opinion: Power conditioners will not help here. An overvoltage / transient protection is very useful, even more important is something that tells you whether you have good earth etc. Some also contain hamonics filter that make sure your attached devices will only get a more or less pure 50/60 Hz sine and no "dirt", e.g. from fluorescent lamps.

I already doubt the Helix would be affected by that though as it has a switch mode power supply - there is almost no way that harmonics from the power line can couple into the DC side of it. So how should it help against hum that not only occurs much deeper down in the circuit, but also in conjunction with another device? Plus, if the hum is at 50/60 Hz, it's not a harmonic, so no filter could ever get that out of the Helix' or the amp head's power.

 

I'm curious to hear whether a power conditioner helped anyone get rid of a ground loop. Until then, I'd like to be the counterweight for those who keep recommending them for all kinds of issues, from noise over hum to tube eating Marshalls.

 

 

You are right. It was not the COAX.

I agree about the Power Conditioner for the most part. Maybe helps with some dodgy electrical runs.

 

I have a heavy duty breaker box, new electrical circuits run, ISOBAR power surge protectors, and heavy duty shielded power cords.

Still get hum from any number of interactions here.

 

The EBTECH is pretty good.

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I know the feeling. I am personally in a bad position.

 

1952 house, on a slab, no grounding, dodgy attic.

 

Meaning.... I'm not running an extension cord through the house from the newer grounded side, AND.... I'm not ripping my walls apart. There is absolutely no grounding option aside from convincing my wife that my studio should be in the new big living room and the tv/furniture should be in the old one. I'm simply not in a position to pay for or do the work, and I used to be a framer; I know a good amount of what's involved (though not an electrician).

 

With that mouth full out of the way.

 

I popped a gfci outlet in there (yes I understand it isn't grounded, but a large spike from one side to the other it'll catch... it's that or nothin. And yes my two prong outlets have been switched to 3 prong even though they aren't grounded... save the criticism. Lol)... I have two florescent lamps in there. Replacement is in the works, but again, not at this exact moment. Shares a breaker with the bathroom, my son's room, and my mother in laws room (yes, she moved in with us. HEY!!! Ya wanna know what REEAAAALLLLYYY good for tour sex life?!?!?! When the master bedroom shares one wall with your mother in law and another wall with your 4 year olds room!!! It's awesome!)

 

So it's about as bad as it gets.

 

Now whats still being run off of this electrical nightmare:

 

2x JBL prx715

2x JBL prx718xlf

2x 8" studio monitors

2 computers

Midas m32r

Routers

dbx pa2

Helix

Wireless systems

Road King amp

And the wonderful florescent lamps

 

Then there's the space heater in my son's room, the florescent lamps, tv, etc in my mother in laws room, and whatever in the bathroom.

 

It's deeeaaad silent...

 

Quite literally the chain is gfci > cheap power conditioner (I know their generally useless, but it was $50 for a rack mount power strip in my eyes) > that to another power strip mounted on my desk > everything else.

 

The only two things in this room designed to stop anything like that is the cheaply power conditioner and the ebtech hum eliminator.

 

Band practice, lessons, recording, everything all on at once and volume cranked... quiet as a mouse when no signal is passed through any speaker.

 

 

Basically, if I can get silence with this situation. There's gotta be a simple fix you can use.

 

 

Oye that was a mouth full.

 

 

I was slightly ranting as well. Lol

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I'm still messing with using Helix with tube amps, in (more than 4) cable method

 

I have a passive two channel Ebtech that is working reasonably well; though I just picked up a Radial Shotgun, which is probably overkill; though I have some ideas about using the second set of outputs for looper related sends.. Not 100% this is the right solution, but figured it's worth trying out!

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I'm still messing with using Helix with tube amps, in (more than 4) cable method

 

I have a passive two channel Ebtech that is working reasonably well; though I just picked up a Radial Shotgun, which is probably overkill; though I have some ideas about using the second set of outputs for looper related sends.. Not 100% this is the right solution, but figured it's worth trying out!

 

I now have my two Marshall tube amps using the 7 cable method connected to the TS outs along with the send/returns and two studio monitors connected to the XLR outputs.  I have to say I love it.  Way more than I need, but why not?  Luckily I have very little noise or hum.  :)

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I used an ebtech with my g system and engl amp and have to say it is the quietest rig ive ever had...i mean total silence when holding guitar strings even when cranked...awsome...now i have a helix im gonna rig that up the same way see if i get same results...my only queery is the g system used all trs cables but does the helix have trs jacks or are they all mono?...any ideas?...ill keep you posted on my set up results....great post btw....

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