XLR Hiss (Phantom Power and Helix)

[kronda]

Well, thanks for all the info, guys.

 

I feel really disappointed and share with you all the frustration over this issue. I understand nothing is perfect and as this is the first real issue with Helix that I'm aware of I'm not going to return it. But silence from Line6/Digital Igloo on these matters is driving me quite mad as Helix is supposed to be such a premium piece of gear. That KnowledgeBase item is a joke...

 

I guess the first real ball dropped on the Line 6 side in the Helix playground. Hope for not many more.

[brainbug]

Philosophy
Phantom blocker blocks Phantom power while leaving the audio signal intact. Phantom power can be applied to either the male or the female side of Phantom Blocker's XLR connector and will not reach the opposing xlr connector, the audio signal travels without restriction in both directions.

Applications:

Microphone preamps
Some (older) preamps are sensitive for Phantom power at the input. The preamp's input transformer cannot handle Phantom power from another source. The transformer's thin silk isolations can burn out because a burst of Phantom power switching on creates a high voltage in the input transformer ,to prevent this a complete blocking is needed.

Unbalanced TRS to XLR cables
When connecting an unbalanced TRS to XLR cable pin 3 of the XLR connector is directly connected to ground, creating a short, this can damage input transformers and under-dimensioned phantom power circuits.

Balanced device outputs
Phantom blocker is a great solution to protect the output of any device connected to the XLR input of a mixing desk or preamp which has Phantom power switched on, e.g. your computers audio interface.


Microphones
There are microphones (mainly Ribbon microphones) which do not tolerate Phantom power, to protect your Ribbon microphone against Phantom power we advise FetHead. Connecting a ribbon microphone to a cable which has Phantom power applied sends a rush of current through the microphones transformer, this current gets amplified by the transformer into the primary circuit of the microphone and forces the ribbon out of the magnetic field it is suspended in, this can permanently stretch the ribbon.

Important !

Before connecting the device you wish to shield from Phantom power make sure Phantom blocker is attached, have Phantom power switched on and wait 5 seconds during which Phantom blockers internal bleeder resistors will cancel out voltage differences. Connecting in this order prevents the transfer of an initial AC voltage burst created by the Phantom power switching on.

[brainbug]

Well, now I ordered two of these, as with the band there are no problems as the mixer has individual phantom power switching, but when I play with the duo, the mixer has 6 channels and it's very hard to find a small mixer tha has that feature, so I'm gonna need these blockers.

I thought to share this as they are good and not too expensive.

By the way, I mentioned earlier I had the same problem with a well known japanese brand Keyboard.. I didn't realize at that moment, but when someone asked Line6/Yamaha what they are gonna do, I realized that as the keyboard was a Yamaha, it might not be a coincidance..... 

[ghprestige]

I wanted to weigh in on the "Hiss" problem.  I used my Helix for church worship.  This was the 1st time for live use.  I went out mono XLR (set to mic level) direct into the house sound system.  I was emphatic about phantom power being turned off for my channel.  The extreme Hiss made using the Helix XLR output impossible.  I tried pressing the ground lift and that made no difference.  The Helix internal phantom power was turned off (not that that would make any difference at all).  My main output volume was turned all the way up, but interestingly enough, it did not make any difference where the volume knob was the extreme hiss was the same.  Same goes for volume pedal position.  With volume pedal heel down or heel up the extreme hiss was the same.  The work around was to go 1/4" mono out to DI which completely cured the problem.  After rehearsal the paid sound tech and myself spent an hour trouble shooting to only discover #1. Phantom power was off  #2. There were no bad cables. #3. There was no problem with the stage snake. #4. There was no bad channel on the mixing board.  #5 The only way to get rid of the extreme hiss was to go with 1/4" out into DI.  Very disappointing for the first time live experience. The funny thing about this situation is that at home I go stereo XLR out into CH1 & Ch2 of my Yamaha MG16 inexpensive mixing board.  There is a small amount of hiss but nothing like what I experienced at church.  So, in my case, it doesn't appear that the hiss is caused by phantom power at all.  Maybe power is the culprit here.  It would be nice for Line 6 to weigh in on this problem.    

[Line6Hunter]

I wanted to weigh in on the "Hiss" problem.  I used my Helix for church worship.  This was the 1st time for live use.  I went out mono XLR (set to mic level) direct into the house sound system.  I was emphatic about phantom power being turned off for my channel.  The extreme Hiss made using the Helix XLR output impossible.  I tried pressing the ground lift and that made no difference.  The Helix internal phantom power was turned off (not that that would make any difference at all).  My main output volume was turned all the way up, but interestingly enough, it did not make any difference where the volume knob was the extreme hiss was the same.  Same goes for volume pedal position.  With volume pedal heel down or heel up the extreme hiss was the same.  The work around was to go 1/4" mono out to DI which completely cured the problem.  After rehearsal the paid sound tech and myself spent an hour trouble shooting to only discover #1. Phantom power was off  #2. There were no bad cables. #3. There was no problem with the stage snake. #4. There was no bad channel on the mixing board.  #5 The only way to get rid of the extreme hiss was to go with 1/4" out into DI.  Very disappointing for the first time live experience. The funny thing about this situation is that at home I go stereo XLR out into CH1 & Ch2 of my Yamaha MG16 inexpensive mixing board.  There is a small amount of hiss but nothing like what I experienced at church.  So, in my case, it doesn't appear that the hiss is caused by phantom power at all.  Maybe power is the culprit here.  It would be nice for Line 6 to weigh in on this problem.    

It sounds like somehow there is still phantom power being sent from the mixing board to the Helix itself, especially because the 14" output workaround cured the problem. If you are totally sure that no phantom power was being sent to the Helix, please open up a support ticket so that we can further examine your issue.

 

http://line6.com/support/tickets/

[PeterHamm]

ghprestige. How did it sound going through the 1/4"->D.I. route. reason I ask is that I find the 1/4" output to be virtually the same (maybe even a tad more present) than the XLR anyway.

[ghprestige]

For the most part I got favorable comments about my sound from the 1/4" mono output to DI.  The worship leader said that it was not as warm as my tube amp rig but that it really sat well in the mix.  He told me to not change a thing!  Understand that where I play is a mega church where tube amps rule.  The worship leader actually bought one for himself to use when he leads with electric instead of acoustic.  I can't say that the 1/4" output sounds any better or worse than the XLR output.  With so much hiss coming out of the XLR mono output it is just a sigh of relief when that goes away in our IEM's.  One of our custom tube amp builders said he can tell the difference on my high gain sounds.  He claims that he can hear a difference in the slew rate between the modeled amp and a tube amp.  Not certain what he meant with that statement.  The paid sound tech said it sounded good but not as good as my tube amp rig (Sherlock Fathead, the Big Three Strymon pedals, Double Hotcake...+many pedals all midi controlled). He said since I only had a week to tweak the Helix he thought it was possible to equal my tube amp rig!

 

I may start a support ticket about the Hiss problem because the paid sound tech assured me that phantom power was off.  I did not see the mixing console with my own eyes to verify that.  I may try that in my studio to see what happens there. 

[BigRalphN]

I wanted to weigh in on the "Hiss" problem.  I used my Helix for church worship.  This was the 1st time for live use.  I went out mono XLR (set to mic level) direct into the house sound system.  I was emphatic about phantom power being turned off for my channel.  The extreme Hiss made using the Helix XLR output impossible.  I tried pressing the ground lift and that made no difference.  The Helix internal phantom power was turned off (not that that would make any difference at all).  My main output volume was turned all the way up, but interestingly enough, it did not make any difference where the volume knob was the extreme hiss was the same.  Same goes for volume pedal position.  With volume pedal heel down or heel up the extreme hiss was the same.  The work around was to go 1/4" mono out to DI which completely cured the problem.  After rehearsal the paid sound tech and myself spent an hour trouble shooting to only discover #1. Phantom power was off  #2. There were no bad cables. #3. There was no problem with the stage snake. #4. There was no bad channel on the mixing board.  #5 The only way to get rid of the extreme hiss was to go with 1/4" out into DI.  Very disappointing for the first time live experience. The funny thing about this situation is that at home I go stereo XLR out into CH1 & Ch2 of my Yamaha MG16 inexpensive mixing board.  There is a small amount of hiss but nothing like what I experienced at church.  So, in my case, it doesn't appear that the hiss is caused by phantom power at all.  Maybe power is the culprit here.  It would be nice for Line 6 to weigh in on this problem.

 

You may have covered this but did you try setting the xlr outs of the Helix to Mic level? I believe they are line by default. Some board inputs do not handle line level well. Especially the preamps of some older analogue boards but I have heard of it with digital as well. We actually have to do this with our system. The first time I hooked up hiss was quite loud. I set xlr outs to mic, maxed Helix Volume and then adjusted the boards channel input gain. It is pristine now.

[kronda]

This looks like a nice device but it's not exactly cheap (~$60), more so that we need two of them. Anybody thinks it would be an appropriate gesture from Line 6 to send all current Helix owners (who were not notified about the phantom power problem before buying) two of these for free?

 

Philosophy
Phantom blocker blocks Phantom power while leaving the audio signal intact. Phantom power can be applied to either the male or the female side of Phantom Blocker's XLR connector and will not reach the opposing xlr connector, the audio signal travels without restriction in both directions.

Applications:

Microphone preamps
Some (older) preamps are sensitive for Phantom power at the input. The preamp's input transformer cannot handle Phantom power from another source. The transformer's thin silk isolations can burn out because a burst of Phantom power switching on creates a high voltage in the input transformer ,to prevent this a complete blocking is needed.

Unbalanced TRS to XLR cables
When connecting an unbalanced TRS to XLR cable pin 3 of the XLR connector is directly connected to ground, creating a short, this can damage input transformers and under-dimensioned phantom power circuits.

Balanced device outputs
Phantom blocker is a great solution to protect the output of any device connected to the XLR input of a mixing desk or preamp which has Phantom power switched on, e.g. your computers audio interface.


Microphones
There are microphones (mainly Ribbon microphones) which do not tolerate Phantom power, to protect your Ribbon microphone against Phantom power we advise FetHead. Connecting a ribbon microphone to a cable which has Phantom power applied sends a rush of current through the microphones transformer, this current gets amplified by the transformer into the primary circuit of the microphone and forces the ribbon out of the magnetic field it is suspended in, this can permanently stretch the ribbon.

Important !

Before connecting the device you wish to shield from Phantom power make sure Phantom blocker is attached, have Phantom power switched on and wait 5 seconds during which Phantom blockers internal bleeder resistors will cancel out voltage differences. Connecting in this order prevents the transfer of an initial AC voltage burst created by the Phantom power switching on.

[cletcher1]

I wouldn't count on it...

 

Just to share a quick story as to how this issue has affected me.  I was going to go back to praise band rehearsal last night and let the other guitar player filling in for me this week play through the Helix while I dialed in the settings better, before I left our "worship leader" texted me and asked me not to show up with the Helix until after practice, simply because the noise issue train wrecked practice last week.  Needless to say I was a bit mad.  But that will be another story.

[kronda]

That sucks...

 

I don't count on the phantom blocker give-away at all, just asked what people think. It's issues like this (worked fine on older products from Line 6, not mentioned in manual, no honest word from Line 6 whether it's a "designed feature" :wacko:  or a mistake) that drive me mad and that sticky topic "Why is Line 6 not responding???" doesn't really calm me down as this is exactly a ...thing that I can't easily ignore at this price tag.

 

Anyway, practically it's just "deal with it" or "leave it", nothing will change, and since this can be "solved" by spending additional $120 or less, it's still quite fine. It's just embarrassing - sadly not just for the designer of the product but also for us...

[PeterHamm]

I'm sure that there are a LOT of things that they are dealing with, from feature requests to "bug fixes" and I would bet you real money that they are not even close to ignoring this.

But for them to tell you what they are going to do about it, or what can be done about it, or even if it's a physical vs. software problem... before their engineers have totally evaluated it... I'd give them a little time to figure out what can be done about it.

Remember, you are all early adopters. They have a vested interest in you liking their product and company I think.

[kronda]

Perhaps, we'll see but I wouldn't be surprised if the Knowledge Base item is all we'll ever get on this one as I think this hiss problem is not solvable by software update...

[ozbadman]

Perhaps, we'll see but I wouldn't be surprised if the Knowledge Base item is all we'll ever get on this one as I think this hiss problem is not solvable by software update...

 

At the very least, it should be in the manual so when people are at gigs they know what to do.

[kronda]

Hi again,

 

I raised a support ticket to get more info about this issue (sound quality degradation when phantom power is switched on on the channels connected to Helix XLR outs) and asked Line 6 whether there will possibly be any fix (firmware or repair) available. This is the response I got from Line 6 Will:

 

...

 

"I also do not know of any fix that will be done to units to rectify this."

 

I guess it's time to order my two phantom blockers as I plan to start gigging with Helix in January. Even though I consider this a let down from Line 6 (both the actual problem and the non-communication approach) I'm gonna close this issue for myself now. I have to say I haven't played my Helix for a week now because this issue annoyed me so much. Time to get back to it!

[gunpointmetal]

Yeah, sounds like L6 needs to start sending out free phantom blockers to early adopters and included them in the box with new-to-ship units.....This is and could be a serious problem for people, and there's no reason we should expect to spend MORE money to be able to DI a device a that is specifically designed to run direct via XLR.... especially considered the company's own flagship mixer can cause the problem.

[phil_m]

I was thinking about this last night, and another workaround that should work without buying actual phantom power blockers is simply using an XLR to 1/4" (TS) cable and taking that into a direct box. The direct box would block the phantom power as well. Of course, if you're not using the 1/4" outs for anything else, you might as well just use those. But if you're using the 1/4" outs for something else and still want to use the XLR outs, those little XLR to 1/4" cables can be bought for under $10, maybe under $5. Most places that have sound systems have direct boxes laying around. It's a little weird, because you'd be going from balanced to unbalanced and then back to balanced, but as long it's a short cable, it really doesn't matter much.

 

Of course, the easiest thing is to just turn phantom power if possible.

[gunpointmetal]

I was thinking about this last night, and another workaround that should work without buying actual phantom power blockers is simply using an XLR to 1/4" (TS) cable and taking that into a direct box. The direct box would block the phantom power as well. Of course, if you're not using the 1/4" outs for anything else, you might as well just use those. But if you're using the 1/4" outs for something else and still want to use the XLR outs, those little XLR to 1/4" cables can be bought for under $10, maybe under $5. Most places that have sound systems have direct boxes laying around. It's a little weird, because you'd be going from balanced to unbalanced and then back to balanced, but as long it's a short cable, it really doesn't matter much.

 

Of course, the easiest thing is to just turn phantom power if possible.

I've never trusted a venue to have anything, ever, and I'm usually better for it. There shouldn't need to be a workaround for this, and since there is, L6 should provide it for us, since they f*&ked the design in the first place.

[phil_m]

I wonder if the reason it's an issue might not have to do with the fact that the XLR outs are auto-sensing in the sense that they need to be able to tell the Helix when only one is connected so that the XLR outs automatically sum. I don't know enough about the actual circuit, but I could see that it came down to a decision like, "well, we can do this, but you have to give up this...". Such is the reality of design a lot of times.

[kronda]

I was thinking about this last night, and another workaround that should work without buying actual phantom power blockers is simply using an XLR to 1/4" (TS) cable and taking that into a direct box. The direct box would block the phantom power as well. Of course, if you're not using the 1/4" outs for anything else, you might as well just use those. But if you're using the 1/4" outs for something else and still want to use the XLR outs, those little XLR to 1/4" cables can be bought for under $10, maybe under $5. Most places that have sound systems have direct boxes laying around. Of course, the easiest thing is to just turn phantom power if possible.

 

Sure but my experience is that we're playing 

 

EITHER a better-equipped place and there is a large mixer with phantom switches on all individuall channels and there indeed are a few DI boxes laying around (not needed for Helix)

 

OR we're playing a really small place where there is a small mixer with just a single phantom switch for all channels and then the soundguy just has (at most) a single (crappy) DI box which (ooops) he'll have to use for our keyboard player. Bummer.

 

There are definitely many solutions, yours possibly being the cheapest but it would just all be the easiest if the Helix was designed well...

[gunpointmetal]

I'd take non-summing over possibly noisy connections any day. It's pretty easy to build centered versions of patches if that situation were to arise, then summing wouldn't matter, and that's actually a logical workaround to a minor issue, whereas me spending extra money on cables, DI boxes, phantom blockers, modding cables, whatever, is a "fix" for a problem that shouldn't exist. 

 

I'm not trying to argue with people on this subject, but there really isn't a reasonable justification from a design or functionality standpoint, and if there is, why can't Line6Hunter or DI say so now, since we're talking about it.

[kronda]

I wonder if the reason it's an issue might not have to do with the fact that the XLR outs are auto-sensing in the sense that they need to be able to tell the Helix when only one is connected so that the XLR outs automatically sum. I don't know enough about the actual circuit, but I could see that it came down to a decision like, "well, we can do this, but you have to give up this...". Such is the reality of design a lot of times.

 

That's why I would love to hear an honest story from Line 6. Perhaps it was some kind of trade off. I would then think the decision was wrong but perhaps understandable as they had to make a judgement call. But honestly the silence just means to me it was a screw up that they don't want to comment on as that would spread a negative word about Helix much further than to these discussions.

[cletcher1]

Maybe we could start a petition in this thread. If you'd like to see a more official response from Line 6, just post "bump". Maybe if the list gets big enough....

[kronda]

I'm not very optimistic about bringing democratic principles into business but I guess it's clear that I'd like to hear from Line 6 so...

 

Bump

[a2dconverterguy]

Since I'm on my Holiday / Stay-home Vacation; I have had time to tinker with electronics...(that's what I do when I'm not on vacation as well  :D )

 

I built a dual channel Phantom Power Blocker.... The Female XLR pig-tails plug into the HELIX. The box filters the DC from the Mixer via 2 Male XLR outputs and provides indication of the presence of 48 VDC on each channel via a red LED...  I also added a ground lift on the box to make it more useful...

 

It took a while to acquire the parts, fabricate the circuit board, drill the die-cast box etc... I made it for my own use.. (It is not something that I want to produce as the blockers on the market today are cheaper than what I would have to charge for my time :( )

 

I hope that you enjoy the pix..

 

seeya

 

Joe

 

[kronda]

Very nice work! :)

[klangmaler]

I'm not very optimistic about bringing democratic principles into business but I guess it's clear that I'd like to hear from Line 6 so...

 

Bump

...guess Line6 should explain, if we all should use our "Holiday / Stay-home Vacations to tinker with electronics" ;-)

Knock, knock, knock - anybody?!

[brainbug]

a2dconverterguy... It would be nice and appreciated if you could post the schematics and board layout..  :rolleyes:...... just because everybody can build his own if needed as L6 is not going to help apparently. Thank you for your post anyway 

[a2dconverterguy]

a2dconverterguy... It would be nice and appreciated if you could post the schematics and board layout..   :rolleyes:...... just because everybody can build his own if needed as L6 is not going to help apparently. Thank you for your post anyway 

 

 

 

Please find the design below for a one channel power block...not to scale...

 

 

now the legal mumbo jumbo...

 

"I claim no responsibility for damaged equipment from mis-connection, error or any other problem that may arise from the use of this design."

 

The design is based on two sources...

 

https://www.gearslutz.com/board/attachments/geekslutz-forum/232400d1304024213-phantom-power-blocker-phantom-blocker.pdf

 

http://circuitlab.com/cf3e79a

 

I hope this helps.

 

seeya

 

Joe

[aerosol_d7]

HelixX or 2 wil have it fixed

[ge31]

I discover the problem today during my rehearsal with my band, very disappointed ...

[capdoogie]

Well, I returned mine. I purchased to early. Will wait till more things have been addressed. Will be trying out the Kemper soon.

[phil_m]

Well, I returned mine. I purchased to early. Will wait till more things have been addressed. Will be trying out the Kemper soon.

 

Kemper recommends disabling phantom power when connecting to a mixer as well, for the record...

 

From the Kemper manual:

 

The XLR outputs are protected against 48V phantom power fed by a mixing desk. However, you should avoid feeding phantom power into the Profiler if you want the best audio quality. Like all inputs and outputs, it offers a GROUND LIFT to prevent a hum loop.

[brainbug]

I always plug my Kemper in any desk, phantom or not phantom, and no troubles at all, just like I used to do it with the old HD500, and no troubles whatsoever...

[brainbug]

P.S. I did not return my Helix because it's great anyway, but I had to purchase the stuff mentioned above to be able to use it properly

[capdoogie]

Don't get me wrong I'm a long time line 6 user from the initial day. Just couldn't cope with some things and issues. Maybe later I'll get another one but for now going a different route. And who knows that could end the same way.

[djy8131]

Sescom SES-IL-PPB XLR Inline Phantom Power Blocker

The SES-IL-PPB removes harmful phantom power from energized microphone inputs when phantom power isn't required. The SES-IL-PPB protects expensive and sensitive ribbon mics, dynamic mics, direct boxes, splitters and other devices not compatible with phantom power. It features complete passive circuitry to keep your audio signals distortion & noise free. A perfect addition to any audio run bag.

 

 

 

I bought one of these for about $35 at BandH Photo.  Although it was a little annoyed to have to buy it, I like the Helix too much to get rid of it!

[brainbug]

Yeah.. for people in USA that is the cheaper choice .. For Europe is cheaper the Triton Audio .. They are both the same

[capdoogie]

This it what makes me so mad! Doesn't line 6 make their products for the real gigging musician. The helix was supposed to be the holy grail for gig and go. But it's slow preset changes and the issues above make me wonder who test these things. Bedroom only players? Come on line 6! Sorry just ranting.

[GlennDeLaune]

Anybody experiencing audio clipping when running Stereo XLR out of Helix direct to FOH Snake?