Helix->amp->attenuator->IR noisy

[matsraknerud]

Hi. 
I would really like to add my tube amps to my helix setup. But whatever I do I can’t seem to get the noise floor low enogh. The type of noise is hiss, not hum or cracke. Like adding a high gain distortion in the chain. 

Ground loop is not an issue. I’ve try with and without radial SB6 isolator both on the send and return. 
I have also tried both line and instrument level on both send and return. 
The only time I got the noise floor to an acceptable level was when I used line level on send (and return) and cranking up the level in front of the send by adding a gain block in front of the send. But then I would clip the output (send1) when hitting the guitar hard. 
This makes sense in terms of gain staging. By raising the signal as far towards clipping as early as possible in the chain would give the best signal/noise ratio. But that I would have to have less than 0dB headroom in the digital domain to give a somewhat quiet output seems odd to me. 
 

The amps I’ve been using is overdriving a bit which of course makes it harder to get the noise floor down. But any way, it should be possible. 
 

Been in touch with line6 support, and they say I should have it serviced by a tech. But I bough it second hand and would have to pay the repair myself. And I’m worried it’s just the design of the helix that is the problem since I have the exact same problem when I try do to this with my hx stomp. 
 

Anyone out there having luck with this helix-amp-attenuator-helix approach?

[Schmalle]

I would set Send/Return levels to Inst to get the same level as if I plug directly into the amp. This way the noise floor is the lowest, too.

 

Try

• some Helix overdrive pedals and lower amp gain.
• boosting treble with a Shelving EQ (2500Hz maybe?) before the amp and reduce treble on the amp.
• a Horizon Gate after the attenuator .

[matsraknerud]

Thanks for answering. Good tips. But unfortonately the amp overdrive is what I want. So od pedals before amp is not actually an option. It works for sure, but then I’m just as happy with staying inside the helix. 
noise gate is not sounding very good in my opinion. 
 

I think I might just forget about the idea of having an amp in the loop. Have searched around a lot, and it’s pretty clear I’m not the only one finding the noise floor on the outputs too high. 
 

Just to be clear. Using the helix standalone going to FOH is dead quiet. Even with high gain amps.

[rd2rk]

One thing I found that helped when using a tube amp - I've had two (an Engl and an Egnater) and only one (the Engl) had that problem - was to use the SEND on FX Loop 1 set to INST, and the RETURN on FX Loop 2 set to LINE. Might not fix your problem, but worth a try.

[matsraknerud]

Thanks. I have tried that. Didn’t help much. The noise is generated at the loop output of the helix. If I unplug the cable between loop send and amp input the hiss goes away. 
 

All cables are testet. 
I’ve also tried with other outputs including the main 1/4 inch. Same result. 
 

Hiss is the same even with nothing connected on the input of the helix. 
 

turning down or up the fx send level also has very little effect on the noise. There’s allways this blanket of hiss. 
 

I’m really not that picky about this stuff. Been playing noisy single coils for many years. But I’ve allways been able to turn down guitar volume and be silent. 

[rd2rk]

If what you are saying about the noise being generated by the Helix were true, then that noise would exist with every amp. My current amp's FX loop (Catalyst100) is effectively silent, as was the Egnater, while the Engl I had was noisy. The Helix FX loop is not absolutely silent, there is a tiny amount of noise added, but it should be imperceptible. Do you have an external AI (soundcard)? Using a blank preset try connecting the send to one of its inputs and use a meter (in a DAW?) to check for noise on the send. In Global Settings>Ins/Outs be sure to set the send to the level expected by the AI's input.

[matsraknerud]

Here you can hear me playing a little bit with an almost in tune guitar :)

First you hear the amp sim, then I roll down the guitar volume. The noise goes away. All good.
Then I switch to the fx loop with a marshall in the loop. As you hear the noise is constant even though I roll down the volume after playing.
Then I switch back and forth between amp sim and marshall with the guitar volume down.

If the amp in the loop is set pretty clean i agree that it's not much of an issue, but with a cranked marshall it's a bit too much.

 

[Schmalle]

On 10/27/2022 at 8:05 PM, rd2rk said:

If what you are saying about the noise being generated by the Helix were true, then that noise would exist with every amp. My current amp's FX loop (Catalyst100) is effectively silent, as was the Egnater, while the Engl I had was noisy. The Helix FX loop is not absolutely silent, there is a tiny amount of noise added, but it should be imperceptible. Do you have an external AI (soundcard)? Using a blank preset try connecting the send to one of its inputs and use a meter (in a DAW?) to check for noise on the send. In Global Settings>Ins/Outs be sure to set the send to the level expected by the AI's input.

An overdriven amp's input stage is very susceptable to added noise, because it's - well - heavily amplifying the input signal. I think the OP is primarily about that.

 

The question is: (How) can the noise floor be reduced on the outputs/sends?

 

 

[matsraknerud]

On 10/27/2022 at 8:05 PM, rd2rk said:

If what you are saying about the noise being generated by the Helix were true, then that noise would exist with every amp. My current amp's FX loop (Catalyst100) is effectively silent, as was the Egnater, while the Engl I had was noisy. The Helix FX loop is not absolutely silent, there is a tiny amount of noise added, but it should be imperceptible. Do you have an external AI (soundcard)? Using a blank preset try connecting the send to one of its inputs and use a meter (in a DAW?) to check for noise on the send. In Global Settings>Ins/Outs be sure to set the send to the level expected by the AI's input.

I have measured the noise level by just adding a fx loop with just a jumper cable in the loop. I can't remember the number, but it's a lot.
Of course this clip has been normalized so you can hear the difference.

[Schmalle]

On 10/27/2022 at 8:33 PM, matsraknerud said:

Here you can hear me playing a little bit with an almost in tune guitar :)

First you hear the amp sim, then I roll down the guitar volume. The noise goes away. All good.
Then I switch to the fx loop with a marshall in the loop. As you hear the noise is constant even though I roll down the volume after playing.
Then I switch back and forth between amp sim and marshall with the guitar volume down.

If the amp in the loop is set pretty clean i agree that it's not much of an issue, but with a cranked marshall it's a bit too much.

 

That noise does not indicate a defective unit and sounds like normal behavior of the Helix. IMHO

[rd2rk]

Using a blank preset, I added an FX Loop and ran it through my Cat.

With Gain, Channel Volume and Master dimed, I switched between the Clean and High Gain amps.

 

Clean - no noise.

High Gain - Noisy AH.

 

I then took the Helix completely out of the picture - guitar>amp input>amp output>speaker.

Switching between Clean and High Gain, same result.

 

I think you're hearing the sound of a high gain amp. The FX Loop MIGHT be adding a tiny bit to the overall noise, but not much.

 

I don't know how to fix this.

[matsraknerud]

On 10/27/2022 at 9:42 PM, rd2rk said:

Using a blank preset, I added an FX Loop and ran it through my Cat.

With Gain, Channel Volume and Master dimed, I switched between the Clean and High Gain amps.

 

Clean - no noise.

High Gain - Noisy AH.

 

I then took the Helix completely out of the picture - guitar>amp input>amp output>speaker.

Switching between Clean and High Gain, same result.

 

I think you're hearing the sound of a high gain amp. The FX Loop MIGHT be adding a tiny bit to the overall noise, but not much.

 

I don't know how to fix this.

Yes, my marshall is making a bit more noise than the helix. about 6dB more. That I can live with.
But when plugging helix into the marshall it adds more than 6dB of noise on top of that. Which makes the noise floor more than 12dB's higher with the marshall inserted than with just amp sim. And 12dB more noise is a little more than what I'm comfortable with.

Here's another audio clip showing these differnces.
First you hear - amp sim
then - marshall inserted
then - marshall inserted, but unplugging the input of the amp

[dainis718]

I have the same problem with hx stomp. Just bought my self a Marshall jvm410h  and wanted to connect the stomp to it with 4cbl method but on high gain channels it started to hiss. When i put it in fx loop only, the hissing is not there. It only hisses when i connect the stomp to the preamp of the marshall. The only way i found is to put a noisgate bluck in 4cbl method after the marshall preamp, and set it with pretty high treshold.