Unity Gain

[trancegodz]

Something doesn't make sense about this. If you start with the 4CM test preset and bypass the amp's loop (I'd probably also unplug the cables from the amp fx send/return) you'll end up with the same signal path as a 2CM test preset. Does that actually change the level hitting the preamp? It shouldn't. Nothing would change in the In1 - Out3 part of the signal chain.

I'm wondering if you swapped cables and somehow ran into the thing where the humbuster circuit boosts the level, either due to not plugging the Out 3 cable in all the way, or some other cable jack/wiring issue.

I just did as you suggested but could not duplicate the level boost I was getting with the 2CM before. I also tried using a humbuster cable like I was originally and it worked fine also. Same levels as the 4CM. I also tried unplugging the humbuster slightly and got no signal at all. So it's a mystery to me. I am done trying to figure it out.

I am using all regular cables now with the 4CM method and everything is working fine, so I am happy. Thanks for everyones help and suggestions!

 

[Werpinater]

I just did as you suggested but could not duplicate the level boost I was getting with the 2CM before. I also tried using a humbuster cable like I was originally and it worked fine also. Same levels as the 4CM. I also tried unplugging the humbuster slightly and got no signal at all. So it's a mystery to me. I am done trying to figure it out.

I am using all regular cables now with the 4CM method and everything is working fine, so I am happy. Thanks for everyones help and suggestions!

Maybe accidentally bumped a preset change? But glad to hear it’s working well now!

 

[Greg Ferguson]

It worked fine but was way way louder than just plugging the guitar straight into the amp. It drove the front end of the amp so hard it sounded like I had the amp on 10 instead of 2. Like a hot rodded Marshall on 10. Sounded good but not at all what I was expecting. I was expecting it to sound just like my guitar plugged straight into the amp.

I just did as you suggested but could not duplicate the level boost I was getting with the 2CM before. I also tried using a humbuster cable like I was originally and it worked fine also. Same levels as the 4CM. I also tried unplugging the humbuster slightly and got no signal at all. So it's a mystery to me. I am done trying to figure it out.

Pulling the TRS end of the humbuster out one notch will definitely result in a volume jump…

"If you pull the cable out halfway it will get twice as loud. This is due to the humbuster output design. Don't pull the cable out halfway." [4]

More of Cliff's humbuster comments are in "Humbuster cable".

And, you don't say, or maybe I didn't find where you did, but the TRS end of the humbuster cables must be plugged into the modeler; The cables will do no good if they're not. This is mentioned in the manual on p. 6, but not in Section 4's "4CM" page.

---

PS - @Admin M@ , it might help to add some words in the 4CM page saying the TRS ends go into the modeler.

 

[Vecordia]

That's not right. For unity gain you set the knob fully CW.

I suspect your Input 1 Gain is not set to 1.0 in the I/O menu.

Does the statement that out knobs fully CW provide unity gain is also true Out 1 and 2 knobs?

I have been trying to find an answer to this for a long time. There are tons of posts talking about this topic, but I never I found a conclusive answer for the Axe Fx III. The manual indicates that knobs 3 and 4 must be fully CW for unity gain, but does not clarify where Unity Gain is for knobs 1 and 2. I assume that this distinction implies that 1 and 2 provide unity gain at a different setting, but which is it? Is it noon = Unity Gain?

From the manual:

” Output Level Knobs 1–4 — These knobs independently control the volumes at the corresponding rear panel outputs. The Output 1 knob simultaneously controls Output 1 XLR jacks and 1/4” jacks, and the headphones level. Outputs 3 and 4 are at unity gain when set fully clockwise.”

 

[Rex]

Does the statement that out knobs fully CW provide unity gain is also true Out 1 and 2 knobs?

No.

I assume that this distinction implies that 1 and 2 provide unity gain at a different setting, but which is it? Is it noon = Unity Gain?

That depends on how you’ve got your output set up. For any given setting, youll have to find unity gain yourself.

In practice, most people never have a need for unity gain on those Outputs.

 

[GlennO]

Does the statement that out knobs fully CW provide unity gain is also true Out 1 and 2 knobs?

I have been trying to find an answer to this for a long time. There are tons of posts talking about this topic, but I never I found a conclusive answer for the Axe Fx III. The manual indicates that knobs 3 and 4 must be fully CW for unity gain, but does not clarify where Unity Gain is for knobs 1 and 2. I assume that this distinction implies that 1 and 2 provide unity gain at a different setting, but which is it? Is it noon = Unity Gain?

From the manual:

” Output Level Knobs 1–4 — These knobs independently control the volumes at the corresponding rear panel outputs. The Output 1 knob simultaneously controls Output 1 XLR jacks and 1/4” jacks, and the headphones level. Outputs 3 and 4 are at unity gain when set fully clockwise.”

AFAIK, It's not documented anywhere, but outputs 1 and 2 add 18 dB to the output. So, if you set the level in the 1 and 2 output blocks to -18 dB, those outputs will work the the same as outputs 3 and 4.

 

[Orvillain]

AFAIK, It's not documented anywhere, but outputs 1 and 2 add 18 dB to the output. So, if you set the level in the 1 and 2 output blocks to -18 dB, those outputs will work the the same as outputs 3 and 4.

This is very interesting!

I've been chasing down the reason why when using SPDIF (output 2) I'm not getting unity gain; and yes, the difference between the input and output signals was 18dB. So I guess this would be why.

So I guess the solution would be for me to set my AES/SPDIF level to -18dB to have unity.

 

[sean.e]

So I guess the solution would be for me to set my AES/SPDIF level to -18dB to have unity.

https://forum.fractalaudio.com/threads/aes-effect-loop-input-return-level.176641/#post-2146873

 

[GlennO]

This is very interesting!

I've been chasing down the reason why when using SPDIF (output 2) I'm not getting unity gain; and yes, the difference between the input and output signals was 18dB. So I guess this would be why.

So I guess the solution would be for me to set my AES/SPDIF level to -18dB to have unity.

Either that or adjust the output block level, but those are not optimal solutions. What would be nice would be a routing matrix to allow you to freely connect the analog and digital outs to in and out blocks, described here:

https://forum.fractalaudio.com/threads/i-o-routing-matrix.162651/