Reamping adds major noise - what's wrong? [Solved]

kvebbs

Member
Hi,

I'm trying to set up my AX8 for re-amping, but I'm having major issues with white noise.

1) So Guitar > AX8 of course
2) Split signal in preset so...
a) clean signal goes AX8 FX Loop out > Steinberg UR44 interface using TS-cable > REAPER
b) processed signal goes AX8 Out1 > same interface with XLR cable > REAPER

I record unprocessed and processed sound in REAPER. I pass the unprocessed signal back to a re-amp preset on the AX8 using a line out on my interface, and subject it to the exact same processing - only beginning with an FX Loop block instead of the regular input.

The noise added on the reamped signal makes it unusable. There is a marked increase in noise even without any processing block on in the reamp-preset.

How do I go about reducing noise here?
- I've tried combinations of output levels on the AX8 and how hot I run my interface. I wanted to average -18db on the interface, but I've tried with transients up to -6dB.
- I've made sure levels are matched.
- I've varied how hot the signal from the interface back to the AX8 is.

I have some TRS-cables around. I'm going to try those in desperation soon...

Am I hooking things up wrong? Is there another way to do this?

Sorry, messy post... kind of in over my head here.
 
Thanks for the link. I've feel like I've tried just about anything at this point, but I'm still kind of stuck. I've run across something I find a bit weird at this point. Not sure if it's supposed to this, so I'm expecting to get schooled :)

Test 1: Where is the noise floor?
AX8 set up as normal. Nice safe levels in interface mixer.
Unplug anything going to AX8 inputs.
OUT1 into Reaper DAW.
Load preset with chain Instrument Input > a dist, an amp and a cab > to OUT 1.
Result: Silence.
Normalize that silence in Reaper: the much expected noise floor, 80-something dBs boosted.

Test 2: Where is it with the FX Loop as source?
Delete blocks fetching input from Instrument input.
Add fx-loop block as start, running to same dist, amp and cab preset > OUT1.
Instantly a lot more audible noise.

Conclusion from tests 1 and 2: Yes, there is a noise floor from basic chain. Interface probably shares responsibility for it. A lot more of it is coming from just turning FX Loop on. Worst, of course, is it when something is plugged into the FX Loop as well.

Test 3: An accident.
Drop part of cable whilst tidying up listening to noise from above signal chain and thinking.
Have that cable (very lightly) hit AX8 and make a nice sound in OUT1 signal going to the monitors.
Have weird moment with self.
Tap AX8 lightly with finger...
Hear sound again.
Finger-drum solo ensues!
Disable FX Loop block. Route preset for regular input once more.
Tap with finger. Not a sound.

I thought that was a weird phenomenon. I did not know FX Loops did that. Maybe they do?

Test 4: Explore phenomenon
Return to preset beginning with FX-loop block.
Tap lightly. It sounds a lot like a microphone. Like it's inside the box.
Does it work like one?
Why, yes! That's remarkable. Either that, or I'm going crazy.
Record regular guitar with regular input, peaking at -6dB.
Record tapping - lightly - which peaks at -21 dB
Note that this figure is pretty substantial.

Test 5: Record hit song
Press record.
Put face over AX8.
Sing "I want to sing in FX loop, I want to sing FX!!" to the tune of Queen's Bicycle.
Boost by about 35 dB
Record regular input chain.
Sing when doing that as well, for the sake of evidence.
Boost by about the same amount of dB.
Presto: FX Loop with singing vs. regular noise floor.

Render and share mystery. Since I can't share mp3-files here yet, or links, I can only say I've put it up on

soundcloud/grand-elk

It's called FX Loop noise.

WARNING: Turn your volume down and then up. This is not a pretty song. If you care, the lyrics go "I want to sing in FX-loop, I want to sing FX!".

I promise you I'm not making this up. I should be recording right now, not standing on all four with my face to the AX8 singing a Queen song, hehe.

So, two questions:
1) If my interface is the source of noise, that noise pales in comparison to the noise coming from the FX Loop block when turned on alone. Is it supposed to do that?

2) When FX Loop is on, my AX8 acts like a (bad) microphone. Is it supposed to do that?
 
Thanks for the link. I've feel like I've tried just about anything at this point, but I'm still kind of stuck. I've run across something I find a bit weird at this point. Not sure if it's supposed to this, so I'm expecting to get schooled :)

Test 1: Where is the noise floor?
AX8 set up as normal. Nice safe levels in interface mixer.
Unplug anything going to AX8 inputs.
OUT1 into Reaper DAW.
Load preset with chain Instrument Input > a dist, an amp and a cab > to OUT 1.
Result: Silence.
Normalize that silence in Reaper: the much expected noise floor, 80-something dBs boosted.

Test 2: Where is it with the FX Loop as source?
Delete blocks fetching input from Instrument input.
Add fx-loop block as start, running to same dist, amp and cab preset > OUT1.
Instantly a lot more audible noise.

Conclusion from tests 1 and 2: Yes, there is a noise floor from basic chain. Interface probably shares responsibility for it. A lot more of it is coming from just turning FX Loop on. Worst, of course, is it when something is plugged into the FX Loop as well.

Test 3: An accident.
Drop part of cable whilst tidying up listening to noise from above signal chain and thinking.
Have that cable (very lightly) hit AX8 and make a nice sound in OUT1 signal going to the monitors.
Have weird moment with self.
Tap AX8 lightly with finger...
Hear sound again.
Finger-drum solo ensues!
Disable FX Loop block. Route preset for regular input once more.
Tap with finger. Not a sound.

I thought that was a weird phenomenon. I did not know FX Loops did that. Maybe they do?

Test 4: Explore phenomenon
Return to preset beginning with FX-loop block.
Tap lightly. It sounds a lot like a microphone. Like it's inside the box.
Does it work like one?
Why, yes! That's remarkable. Either that, or I'm going crazy.
Record regular guitar with regular input, peaking at -6dB.
Record tapping - lightly - which peaks at -21 dB
Note that this figure is pretty substantial.

Test 5: Record hit song
Press record.
Put face over AX8.
Sing "I want to sing in FX loop, I want to sing FX!!" to the tune of Queen's Bicycle.
Boost by about 35 dB
Record regular input chain.
Sing when doing that as well, for the sake of evidence.
Boost by about the same amount of dB.
Presto: FX Loop with singing vs. regular noise floor.

Render and share mystery. Since I can't share mp3-files here yet, or links, I can only say I've put it up on

soundcloud/grand-elk

It's called FX Loop noise.

WARNING: Turn your volume down and then up. This is not a pretty song. If you care, the lyrics go "I want to sing in FX-loop, I want to sing FX!".

I promise you I'm not making this up. I should be recording right now, not standing on all four with my face to the AX8 singing a Queen song, hehe.

So, two questions:
1) If my interface is the source of noise, that noise pales in comparison to the noise coming from the FX Loop block when turned on alone. Is it supposed to do that?

2) When FX Loop is on, my AX8 acts like a (bad) microphone. Is it supposed to do that?

This is because you are applying gain after the loop, probably lots of it. Any circuit will be microphonic to some degree due to the piezoelectric nature of capacitors. When you apply 60 dB or more of gain with an amp block you're going to amplify that. You shouldn't be using the FX loop for reamping. It isn't designed for that.
 
This is because you are applying gain after the loop, probably lots of it. Any circuit will be microphonic to some degree due to the piezoelectric nature of capacitors. When you apply 60 dB or more of gain with an amp block you're going to amplify that. You shouldn't be using the FX loop for reamping. It isn't designed for that.


Thanks for working weekends man!
 
This is because you are applying gain after the loop, probably lots of it. Any circuit will be microphonic to some degree due to the piezoelectric nature of capacitors. When you apply 60 dB or more of gain with an amp block you're going to amplify that. You shouldn't be using the FX loop for reamping. It isn't designed for that.

Sweet. Thanks for replying, on sundays no less! Good to know. :) At least I got a good song out of it.
 
Good question. Seems line out > re amp box > regular input would be the way to go then? Anyone tried that? Don't have re amp box.
 
I solved this problem last week, and now have completely silent reamping.

Here's what I did.

Guitar - Lehle P split - AX8 - UAD Apollo Interface -Cubase Track
.............Lehle P Split - directly into Instrument input on UAD Apollo -Cubase Track

Now, to Reamp, I think you will have to use a Radial X-amp. I was skeptical that this would get rid of all the noise, but it totally did. Seriously!

The signal follows:
Direct Track -Cubase Out- Radial X-amp in - AX8 -UAD Apollo In -Cubase

The key problem that the Radial x-amp solves is the impedance mismatch from the Interface to the Inputs on the Ax8. Both inputs on the AX8 are 1 megaohm.

The other thing is to avoid getting your direct signal from the AX8. It will introduce a small amount of noise that you can't hear until you reamp it through the AX8 again. That noise get's amplified big time if you reamp with gain.
 
I solved this problem last week, and now have completely silent reamping.

Here's what I did.

Guitar - Lehle P split - AX8 - UAD Apollo Interface -Cubase Track
.............Lehle P Split - directly into Instrument input on UAD Apollo -Cubase Track

Now, to Reamp, I think you will have to use a Radial X-amp. I was skeptical that this would get rid of all the noise, but it totally did. Seriously!

The signal follows:
Direct Track -Cubase Out- Radial X-amp in - AX8 -UAD Apollo In -Cubase

The key problem that the Radial x-amp solves is the impedance mismatch from the Interface to the Inputs on the Ax8. Both inputs on the AX8 are 1 megaohm.

The other thing is to avoid getting your direct signal from the AX8. It will introduce a small amount of noise that you can't hear until you reamp it through the AX8 again. That noise get's amplified big time if you reamp with gain.

This is basically my approach that I talked about in another thread. Only thing I do different via UAD's recommendation is I go out of protools to virtual 1/2 ~ out line 3/4 of the Apollo (making sure you change cue outputs). Then out of my reamp box ~ into input one of the ax8. Out of output one and into line 1 via Apollo not instrument in because on the twin it automatically switches to hi-z on that input and we want to remain line. Been running it this way for abt 6 months with Zero issues via noise ect. Best part abt it is I can mess with tones in the mix prior to printing reamps , it's a beautiful thing . : D
 
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I've set this issue as solved now and ordered a re-amp box.

This seems to be the most correct way of doing reamping with AX8
1) Plug guitar directly into interface, or via DI-box if you don't have the correct input
2) Go line out from interface to re-amp box
3) Re-amp box to instrument input on AX8
4) Regular AX8-out to interface

If you've stumbled across this thread and find yourself short on cash for a reamp box from Radial, as I do, I stumbled across this http://www.soundonsound.com/reviews/orchid-electronics-amp-interface which seems to be acceptable.

Might add comment on how this goes later.

Cheers, and thanks for all the help!
 
I find it weird/unlikely that AX8 should add more noise than your average DI box / audio interface.

I understand that a re-amp box might be needed, but the initial DI should not be necessary. Maybe @FractalAudio or @Danny Danzi can share their experience in this regard?

EDIT: I will get my hands on a Focusrite ISA One tonight, so I can compare all kinds of DI (Guitar->Interface; Guitar-> DI->Interface; Guitar->DI (thru)->AX8->interface;Guitar->AX8->Interface)
 
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Thanks for the recommendation of Orchid Electronics - I never heard about them, but it looks like they sell solid units at a very reasonable price. Depending on a few tests tonight, I will try their amp interface/re-amp box.
 
About Noise
When reamping, I also use a virtual out on the UAD Apollo, which then sends the direct signal from Cubase to line out 3 on the UAD Apollo. From there it goes to the Radial X-amp, and then into input 1 on the AX8. Then, Output 1 from the AX8 to the line in on the UAD Apollo, which then goes to Cubase.

Its also very very very important to set the levels properly. Once you have a nice strong, quiet direct signal recorded, and you send it to the Radial X-amp, the Radial X-amp has a clip meter to help you ensure the signal being sent to it is as strong as possible without clipping. The Radial X-amp also has a gain knob that allows you to control how much of that signal gets sent to the Ax8 input 1. You want to have this signal strong like your ordinary guitar signal -you can use the AX 8 input meter to adjust this.

To have the lowest possible noise floor, when recording the direct signal, I believe you need to avoid any unnecessary A/D D/A conversions. That's why I said I go from the guitar into the Lehle Psplit, take one signal and go directly into the instrument in on the interface, and the other signal goes into the AX8, which ultimately gets recorded wet onto a separate track. The Lehle Psplit isolates the two signals, and therefore avoids ground loop issues.


About Latency
Finally, an important note when Reamping and latency with Cubase (and any other decent DAW).

Cubase normally adjusts for any inherent latency as far as your interface goes. Cubase communicates with your interface and "knows" the latency associated with your settings. It then positions your track exactly where it should go when recording. When you record under normal conditions with the AX8, there is some small additional latency that cubase doesn't "know about". However, we naturally adjust our playing for the very small latency the AX8 introduces, and all is well.

When reamping, you are no longer playing the track, and you cannot compensate for the latency introduced by the AX8. To test if this was a problem, I zoomed in on the direct track, and the Reamped track, and found that under my settings, the reamped track was about 70 samples behind the direct track -this makes sense as it takes time for the signal to make a round trip through the Ax8. Cubase can't measure and adjust for this automatically. To solve this problem, when reamping, I set the "adjust for record latency" manually to 70 samples. The direct track, and reamped track then line up perfectly.

So, after obsessing about this for a week, I was able to get totally silent Reamping results, where the tracks lined up perfectly. :)
 
I think cubase and most other DAWs has a function to measure the round trip latency with outboard gear and compensate automatically.
 
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