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damien_

Very noisy FX loops

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Hi,

 

It seems like my FX loops are very noisy.  I have this external pedal (Maxon AF-9) that I would like to integrate into my signal chain.

 

If I put it between my guitar and the guitar in then everything is perfect.

 

But whenever I put it in the FX loops I get this loud noise even if the pedal isn't powered.  When I plug the AC cable it's even louder.

 

Moreover, if I don't put anything in any FX loops and add an FX loop block to the signal chain, the same noise is there.  This also reproduces with just Return blocks.

 

My FX loops are set to "Instrument Level" but I also tested "Line Level".

 

Anybody had this issue?  It can be tested really quickly by just adding an FX loop block early in the chain.  The noise is more prominent on heavily distorted sounds (I'm using the ENGL here with drive and master at 8).

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So if you take a brand new patch and place a return in the path and have nothing else you have a lot of noise?

No cable plugged into any send or return?

Unplug your guitar?

Still there?

If that is the case - then you have a technical problem. Submit a support ticket.

 

If what I described does not produce noise, then its something else in your chain.

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Yep:

 

- Brand new patch

- Add an ANGL Meteor with default cab, set drive to 8.0, master to 8.0

- You hear a little bit of noise which is typical of highly distorted sounds I suppose

- Before the ANGL, add an FX loop block (any loop, it doesn't have to have anything plugged in it)

- Notice the much louder noise.

 

This is regardless of whether a guitar is plugged in the Helix.

 

Anybody can reproduce this problem?

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Just out of curiosity, in that simplified patch, if you run a cable directly from the send to the return, is there less noise? If the return's not a shorting jack, and it's just sitting open feeding a high gain amp, it wouldn't surprise me if that was noisy.

 

In real life you have your outboard pedal there, so the same sorts of considerations apply to its inputs.

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You didn't actually do the test. No amp. Just a send. Nothing else. Is there the noise problem?

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I tried putting an FX loop block in front of the ANGL amp block, and yes, even with nothing in the loop, if the loop is on, it is quite noisy. I think it just that there is a little amount of noise added inherently, but when you put that in front of a high gain amp, that noise is multiplied (that's what high gain means, essentially), so it makes it really noticeable. With the drive at 8, that's almost making the amp as noisy as it can be. Oddly enough, putting the FX loop block after the amp model actually lowers the noise floor by quite a bit. In of a clean of mid-gain amp model, the noise isn't nearly as noticeable.

 

You could try putting a noise gate block after the FX loop block. I tried that, and all the noise dropped right away. You'd have to mess with it to see what threshold and decay settings work with your signal, but that might be the way to go.

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I'm not sure what you're sending to or returning from,  but I was informed about one of these here, and they work great! 

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I'm not sure what you're sending to or returning from,  but I was informed about one of these here, and they work great! 

 

Well, the noise is there even with the FX loop in the chain and on with nothing actually connected to the send and return, so it's not a ground loop or anything like that. It's just a self-noise inherent with the jack being activated. Putting the loop in front of a high gain amp block really accentuates that noise. It's similar to putting one of the distortion/OD blocks in front of that amp block.

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Well, the noise is there even with the FX loop in the chain and on with nothing actually connected to the send and return, so it's not a ground loop or anything like that. It's just a self-noise inherent with the jack being activated. Putting the loop in front of a high gain amp block really accentuates that noise. It's similar to putting one of the distortion/OD blocks in front of that amp block.

Welp that's not good. And then again it could be a feature! :P  I'm assuming DI knows so he can ask the devs deal with it? 

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You didn't actually do the test. No amp. Just a send. Nothing else. Is there the noise problem?

 

Putting just a return in an empty patch doesn't add noticeable noise.  Only in front of a high gain amp.

 

 

I tried putting an FX loop block in front of the ANGL amp block, and yes, even with nothing in the loop, if the loop is on, it is quite noisy. I think it just that there is a little amount of noise added inherently, but when you put that in front of a high gain amp, that noise is multiplied (that's what high gain means, essentially), so it makes it really noticeable. With the drive at 8, that's almost making the amp as noisy as it can be. Oddly enough, putting the FX loop block after the amp model actually lowers the noise floor by quite a bit. In of a clean of mid-gain amp model, the noise isn't nearly as noticeable.

 

You could try putting a noise gate block after the FX loop block. I tried that, and all the noise dropped right away. You'd have to mess with it to see what threshold and decay settings work with your signal, but that might be the way to go.

 

I ended up putting a noise gate block right after the FX loop block to alleviate the issue.

 

I'm a little bit surprised though.  Why would the inputs being activated generate any noise on the FX loops?  The Guitar In or Aux In don't generate noise (e.g., when nothing is plugged in, or when setting the Input block as "Multi" with nothing plugged in Aux).

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If the return adds gain, then that would amplify any noise already there in front of the high gain amp model, then amplified further at the amp model. 

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I grabbed a pair of Sony MDR-V6 Headphones (63 Ohms 106dB/mW) with HELIX Headphone Knob at Max and Input Block, Output Block, and Global Settings all at Default to listen to each of HElIX's Amp+Cab Models. I defined a new Preset w/ only 1 Block; an Amp+Cab Block.

 

Here's what I found:

 

Mail Order Twin had noticable low end hum!

Essex A30 had some noticable low end hum (less than Mail Order Twin)!

A30 Fawn Nrm had noticable low end hum (same as Essex A30)!

Matchstick Ch2 had noticable low end hum and increased noise floor (more than the Mail Order, A30, Fawn)!

Matchstick Jump had some noticeable hum and increased noise floor!

Brit Plexi Brt had some increased noise floor!

Brit Plexi Jump had some increased noise floor (more than Plexi Brt)!

Brit P75 Brt (about same as Plexi Jump)!

German Ubersonic had some increased noise floor!

Cali IV Lead had a minor increased noise floor!

Archetype Lead had a slightly increased noise floor!

ANGL Meteor had a significantly increased noise floor!

Solo Lead OD had a noticably increased noise floor!

PV Panama had a noticably increased noise floor!

Line 6 Elektrik had a noticably increasd noise floor!

Line 6 Doom had some noticeable hum and increased noise floor!

Line 6 Epic had a noticably increased noise floor!

 

With an FX Return Block (or an FX Loop Block), regardless if Mono or Stereo, added before the Amp+Cab Block, the noise floor increased perceptibly for all the Amp+Cab Blocks! Even the previously quietest Amps (WhoWatt100, Tweed Blues Nrm, Tweed Blues Brt, Interstate Zed, and others) now had a perceptible noise floor level.

 

For those first listed above, that had already exhibited some degree of noise floor and/or hum, the addition of the FX Block, really caused them to exhibit an increased noise floor. Interestingly, for those exhibing any hum, the level of hum did not increase!

 

The ANGL Meteor and Solo Lead OD were the loudest. The Panama, Elektrik, Doom, and Epic were right up there too.

 

And, Yes. Inserting a Noise Gate or Hard Gate at their default values (regardless if, Mono or Stereo) effectively clamped the noise, nearly eliminating it on most of the amps. The Hum remained.

 

Each Amp Profile obviously has it's own distinct characteristics. For those amps exhibiting any noise floor, each had a noticably distinct sound frequency response characteristic.

 

These are just the ways the electronics of each of the amps (profiled and real world) respond. With a signal source, the Signal to Noise Ratio rendered the background noise floor levels imperceptible.

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These are just the ways the electronics of each of the amps (profiled and real world) respond.

 

Thanks for the effort MusicLaw. I'm assuming that you don't own all of these real world amps,  and you are just making a logical assumption? 

 

With an FX Return Block (or an FX Loop Block), regardless if Mono or Stereo, added before the Amp+Cab Block, the noise floor increased perceptibly for all the Amp+Cab Blocks! 

 

Why would a return block add ANY noise to the signal path before any amp added, if there was nothing sent to that Aux's send input? If the noise is coming from a maxed out return block that's creating/generating  a higher noise floor,  is that what you meant by the responses being normal in real world settings, and is that the norm for a return block to act with no input? Just trying to understand where the noise is coming from exactly.

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Thanks for the effort MusicLaw. I'm assuming that you don't own all of these real world amps, and you are just making a logical assumption?

 

Why would a return block add ANY noise to the signal path before any amp added, if there was nothing sent to that Aux's send input? If the noise is coming from a maxed out return block that's creating/generating a higher noise floor, is that what you meant by the responses being normal in real world settings, and is that the norm for a return block to act with no input? Just trying to understand where the noise is coming from exactly.

Correct, regarding the first assumption.

 

I would not have expected the mere addition (presence) of an unplugged Return or FX Loop Block (either one defined using default values), to have caused HELIX to increase the noise floor as such, and, in differing amounts for the various Amps. BTW, when the Return or FX Loop Block was Bypassed, the Noise Floor returned to what it was otherwise on the HELIX without the Return or Loop Block in the Path.

 

I did not meter the levels; I went by ear.

 

It would be enlightening for Ben or DI to chime in on this, for those of us who are interested in the issue.

 

As a practical matter, there are ways to deal with the scenario in actual use. So, unless this is a correctable abnormality in the firmware, I can work around it.

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Thanks for your investigation MusicLaw.  I think I'm going to open a support ticket.  I would like to know how come FX return blocks add so much noise.  To me, they shouldn't be different than Aux In and maybe even Guitar In.  Again, setting a preset with the Input block set to "Multi" does activate the Aux input, where no added noise is perceptible.

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Good idea for the Support Ticket!

 

Be sure to include the URL of this thread so L6 Support has direct access

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Thanks for your investigation MusicLaw.  I think I'm going to open a support ticket.  I would like to know how come FX return blocks add so much noise.  To me, they shouldn't be different than Aux In and maybe even Guitar In.  Again, setting a preset with the Input block set to "Multi" does activate the Aux input, where no added noise is perceptible.

 

bump !

how is it going with the support ticket ? any further investigation results ?

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I did just earlier today find a Known Issue (from Dec 2015) in the Helix Knowledgebase regarding an FX Loop noise floor increase in the Helix. See: http://line6.com/support/page/kb/_/effects-controllers/helix/helix-sendsreturns-and-the-signal-noise-floor-r788

 

Now, apparently with fw 2.20 there is a Known Issue, of a stepped volume when adjusting the main Volume Knob.

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Sorry I didn't get back to you guys.  I did open a ticket and here's how it went:

 

 

Hi, I'm sorry about the trouble with your gear. The send and returns on the Helix don't have a as low of a noise floor as the guitar input. When those ins and outs are used before a high gain amp, it will raise the noise floor. Totally normal behavior. Let me know if you have any more questions. Thanks, Will - Line 6 Support

 

Then they pasted the message linked by MusicLaw just above.  :)

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Then they pasted the message linked by MusicLaw just above.  :)

 

thanks for the update !

at least we have an official answer instead of having to troubleshoot the damn thing ourselves :-)

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This scenario strikes me as one of those situation where the efforts to change the firmware may not justify the effort of allocated programming resources.

 

Theoretically, Helix's firmware, should be able to truly disable an FX Block's impact affecting a A/D Noise Floor increase -- when the FX Block is the Bypassed state. This would also necessitate that the firmware anticipate that at any moment the Block's Bypassed state could be defeated, thus requiring the A/D to be immediately ready and able to perform. The trade-off may simply not justify the result of improving the noise floor, since when a signal is present the noise floor is not perceived.

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I wish Line 6 would publish actual Technical Specifications of the inputs and outputs like real audio gear. I'd like to know nominal dBv levels, noise floors, and impedance specs of all the I/O ports.

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I have this same problem with my LT. I have tested this with different cables, pedals, and power supplys, and for the life of me cannot get rid of the noisy feedback from the fx loop. I am using one of the loops for the "4-cable method" and have no issues of noise being introduced from that. I am trying to add my whammy ricochet into my rig as the pitch wham effect leaves a lot to be desired. 

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I have no idea if the December 2015 Knowlegebase FX Loop Noise Floor Known Issue is on Line 6's Helix To Do List. It sure would be nice to see it remedied in firmware 2.30 or 3.0.

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This got me thinking about how we used to put a patch cable jumper on some guitarists rigs in the effects loop. You might be able to recreate that with the block placed properly.  I just cant imagine that they tried to be that realistic on amps that had. effects loops as eq and boost would accomplish this.

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Hello,

 

I had the same problem but solved it recently.

 

With a mobius in loop 1 (block bypassed) you can still hear the sound of the modulation in the background, especially if th loop is placed before the dirt.

 

But you can play with the mix parameter. So i've added a controller for the mix (0% when bypassed and 100% when active). This way you can either let the loop active all the time (just playing with the mix parameter) or combining it with the bypass/on (on the same button of course). When the mix is at zero, there is no noise at all...

 

I thought the bypass should behave this way, but actually it's not the case.

 

Hope it helps...

 

Regards,

Cyril

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Hello,

 

I had the same problem but solved it recently.

 

With a mobius in loop 1 (block bypassed) you can still hear the sound of the modulation in the background, especially if th loop is placed before the dirt.

 

But you can play with the mix parameter. So i've added a controller for the mix (0% when bypassed and 100% when active). This way you can either let the loop active all the time (just playing with the mix parameter) or combining it with the bypass/on (on the same button of course). When the mix is at zero, there is no noise at all...

 

I thought the bypass should behave this way, but actually it's not the case.

 

Hope it helps...

 

Regards,

Cyril

 

If you have the trails parameter turned on, the return remains active even if the FX loop block is bypassed, so it is possible that you would hear signal coming from the pedal even with the FX loop bypassed.

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If you have the trails parameter turned on, the return remains active even if the FX loop block is bypassed, so it is possible that you would hear signal coming from the pedal even with the FX loop bypassed.

Sounds logical. Thank you for the explanation.

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If the pedal is plugged in to a power source do you have an isolated power supply?  Also have you tried the ground lift?

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So I had the same problem with my FX loops.  Very noisy even with my external pedal turned off. 

 

For now I'm just adding either a Noise Gate or Hard Gate right after the FX loop in the chain. It eliminated all noise and didn't seem to bother my tone.  For now this will have to suffice.  But i'm still wondering why on earth does it make that much noise?  Makes no sense to me.. 

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Also using the multi input setting raises the noise. I always switch to guitar only as it is quiet compared to multi. Flick through the inputs. Aux input, mic input, send returns all cause noise without anything being plugged in. This is frustrating as using the aux or a return to plug in another guitar results in a noisy signal compared to the lovely low noise guitar input socket especially if you start using any amount of gain thru aux or a return.

 

Question why dont the send returns and aux have as low a noise floor as the guitar input? I sure wish they did !

I love my helix but i wish it had two guitar inputs both with the low noise and variable impedance selector.. as the main guitar input is ace, two wud have been so good.

The aux input just doesn't seem much good for much at all to the point where the return is recommended to be used instead.

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If you have the trails parameter turned on, the return remains active even if the FX loop block is bypassed, so it is possible that you would hear signal coming from the pedal even with the FX loop bypassed.

 

By the way i tried this morning with "trails off" and the noise is still here with the fx loop bypassed. Doesn't matter with this mix workaround anyway.

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I mentioned a problem earlier in the month about send/return to strymon dig where the signal gets dirty rather than the pristine delay I'm used to. 

 

No solution to date

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This is the reason I cannot use OD pedals in the external loops - the noise is horrific (even when using low levels on the pedals), and I couldn't do anything to fix it. And yes, it was set to instrument level.

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I tried this particular situation to the letter as per the OP and could not replicate the problem. Note: I have Helix Floor connected to a gig rack with a Furman M-8 ( Not a high end conditioner) but even going into my house power direct, there was not a noticeable jump. 

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Note:

 

The Helix Knowledgebase Article from December 2015 regarding the Helix FX Loop Noise Floor Level Known Issue (see Posts 18, 19, and 24 in this thread), has apparently been removed from the Knowledgebase, as attempting to access that Known Issue article now resolves in an Error that the Article cannot be found.

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Hello...

 

I have found that the Helix effects loop is just too noisy for high gain amps....it is really bad if you try to use the sends to the input of an external preamp....sounds like a vacuum cleaner running in the background....i also have a Pod HD Pro X rack unit......it seems to produce a lot less noise than the helix effects loop...and you have the option of running your external preamp into the line inputs which is what i do....very little noise from the effects loop in that case....i found that surprising given the Helix is a newer design....for me i have the best of both worlds with the Helix and the Pod HD Pro X....i also like the vintage effects sounds better on the Pod HD Pro X than the Helix....can't wait for the new HX reverbs from Helix though....so it is good to have both... :)

 

 

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58 minutes ago, rpossum said:

That vpd - 1 is especially noisy, but I've just spent some time playing with settings and have found that all of the loops have about 50% more hiss when set to Instrument level vs Line level.

This may be completely obvious to many, but I have been running all loops at Instrument level and have just discovered this. Switched to Line Level and everything is MUCH quieter.

I can not replicate the behavior you report. When I listen I have the same amount of noise at both instrument and line level FX loop or 1/4" Output to any 1/4" Input.
When I measure with RMAA I get the same 111dBA S/N ratio. This is about 12dB better than my Native Instruments Komplete Audio 6 interface but a couple dB worse than Mytek and Apogee flagship interfaces.

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