4CM Hum issue with CA Triptik and AXE FX II XL- have I missed anything?

[Lkdog]

Getting close to it all working great, but still have some hum when using the EFX loop active on the CA Triptik.
Have done quite a few searches, but maybe I have missed something or am doing something wrong.

1) Using two humbuster cables I made for the AXE FX outs to CA Triptik..
2) Running Output 2L to AMP INPUT, and Output 1L to Effects Loop RETURN on CA Triptik..
3) CA Triptik EFX Loop Send back to AXE Input 2L using standard TS cable.
4) Put amp power cord into same Isobar filtered power strip as the AXE FX II
5) Have Output 2 pad boost on 12 db.
6) Have the OUTPUT LEVEL 1 and 2 KNOBS on front of AXE FX II maxed out.

All helped but still have some minor to annoying hum when EFX Loop is active. Dead silent for an AXE FX Drive pedal or COMP in front of amp in the preset patch chain I made.
There is no HISS so the noise floor is good.

I did insert a Gate after the FXLOOP in my preset.
This eliminates the Hum noise when engaged , but impacts the sound a little.
Would prefer to get rid of the hum without using it.

Anything I am missing here? I can use the CA Triptik EFX Loop with other devices in the loop with no hum (Line 6 POD XT Live, Lexicon MX300). Have not tried the 4CM with anything else.

I debated on whether to get an FX8, but thought if I can get the AXE FX II XL working in 4CM then I don't need it and I think even Cliff says there is no need.
This is for studio use only so I am not playing out with this setup.

Is the next step one of the Hum eliminator things like EbtEch HUM X or Hum Eliminator?

Thanks for any input or ideas. I can probably live with just using the GATE after the FXLOOP and call it a day, but, well, you know..........

 

[Rex]

What happens to the hum when you unplug your guitar cable from the Axe?

 

[Lkdog]

What happens to the hum when you unplug your guitar cable from the Axe?

Good question.
Hum is present with no guitar cable plugged into the Axe front input.
Hum is present with no cable going into front of Amp.
Hum disappears when I pull the cable from Axe Output 1L to the EFX loop Return on the Amp.
Hum disappears when I engage the Gate that I inserted after the FX Loop in the preset.

Another thing of note, the Boost/Pad settings have no effect whatsoever since I made the Humbuster cables.
There was some hiss before that went away when I would adjust the BoostPAd setting from 0 db to 12 db so they are doing their job in some ways.

 

[Rex]

Good question.
Hum is present with no guitar cable plugged into the Axe front input.
Hum is present with no cable going into front of Amp.
Hum disappears when I pull the cable from Axe Output 1L to the EFX loop Return on the Amp.
Hum disappears when I engage the Gate that I inserted after the FX Loop in the preset.

From all that, it sounds like there are two possibilities. Either:

1) The hum is being generated by a ground loop at the connection between your amp's FX loop output and the Axe's Input 2 (in that case, something like the Ebtech could help);

-or-

2) The hum is being generated in your amp's preamp (in that case, only preamp surgery will help).

 

[scrockel]

When u turn on the effects loop are the levels the same?
Anything touching eac other?
Hum is almost always power related.
To close to anything? Tvs etc?
What is output 2 boost for?
Just some thoughts...

 

[Lkdog]

From all that, it sounds like there are two possibilities. Either:

1) The hum is being generated by a ground loop at the connection between your amp's FX loop output and the Axe's Input 2 (in that case, something like the Ebtech could help);

-or-

2) The hum is being generated in your amp's preamp (in that case, only preamp surgery will help).

The EFX loop itself was fairly recently upgraded by Alan Phillips to the newer lower noise version using 12AU7 tube instead of a 5751 tube. It is dead quiet when engaged with nothing connected or with other effects devices I have tried in it. Now, the 4CM thing is another animal and maybe creates issues.
I guess FWIW, the level knob on the Loop can function as a master volume but I am not sure what that means in terms of circuitry.

I can try a Hum X. The GC here has them in stock.

Or just live with it if that doesn't work and use the Gate and work to get it at a level where it doesn't impact the tone too much. It's close now and I don't know what I am doing.
To be honest I never use the Noisegate with the Axe Fx so another thing I need to learn anyway. LOL.

 

[Lkdog]

When u turn on the effects loop are the levels the same?
Anything touching eac other?
Hum is almost always power related.
To close to anything? Tvs etc?
What is output 2 boost for?
Just some thoughts...

Not sure what you mean by levels, but the unity gain on the EFx Loop level is 2 o clock so Yes levels of sound are the same as long as kelp that there.
With the Efx loop not engaged there is zero hum if you were asking about that.

I have checked all the cables physically and nothing is touching anything. Good question though.
When I use a Pod Xt Live for effects in the EFX loop, I have to make sure the wall wart power supply is not near anything.

Nothing near the Amp but tons of electronic devices in the basement studio area.
The setup doesn't like something that is for sure.

The Output 2 boost/pad apparently impacts the noise floor for some people and raising it reduces hiss when that is a problem.
It was a related issue before the Humbuster cables were installed.
Now it doesn't matter. I am getting no unusual hiss.

 

[Rex]

I'm not sure what to think of the Hum X. I've never seen UL markings on them, which suggests that they might not be UL listed, and that's a red flag for anything that connects directly to power. My understanding is that they work by inserting diodes into the ground connection. If a surge causes those diodes to fail open, you wouldn't be protected by any ground.

Regarding the FX loop upgrade, lower noise doesn't mean less hum. Hum and noise are different things.

 

[scrockel]

Not sure what you mean by levels, but the unity gain on the EFx Loop level is 2 o clock so Yes levels of sound are the same as long as kelp that there.
With the Efx loop not engaged there is zero hum if you were asking about that.

I have checked all the cables physically and nothing is touching anything. Good question though.
When I use a Pod Xt Live for effects in the EFX loop, I have to make sure the wall wart power supply is not near anything.

Nothing near the Amp but tons of electronic devices in the basement studio area.
The setup doesn't like something that is for sure.

The Output 2 boost/pad apparently impacts the noise floor for some people and raising it reduces hiss when that is a problem.
It was a related issue before the Humbuster cables were installed.
Now it doesn't matter. I am getting no unusual hiss.

Since there are a lot of electronic devices my next though, although may not be easy, would be to move to a different room to test. I had a club i used to play in and i could not use a certain outlet. I always use a furman type power conditioner too. Some people think their snake oil but they work...at least heIp ...also installed humphreys ground elimiators buetween my rack devices and that made a huge difference. That was back when i needed a 12 space rack..now this magic box does it all! I used 4cm with evh 5150 100 watt and its dead silent.

 

[Lkdog]

I'm not sure what to think of the Hum X. I've never seen UL markings on them, which suggests that they might not be UL listed, and that's a red flag for anything that connects directly to power. My understanding is that they work by inserting diodes into the ground connection. If a surge causes those diodes to fail open, you wouldn't be protected by any ground.

Regarding the FX loop upgrade, lower noise doesn't mean less hum. Hum and noise are different things.

Yes, there definitely could be a design element by Carol Ann with this amp EFX loop that makes it not ideal for 4CM with an Axe Fx (or any other unit in 4cm) for some reason.
Agree, low noise has little to do with hum at least in this case.

I don't know about the Hum X either. Claims it is not a ground lift and is safe.......
My guess is it is ten bucks worth of parts, but does its job pretty well for a lot of folks it seems.

Worst case scenario is I use the Gate in the Axe and the tone gets compromised a little bit in some ways.

First world problems we obsess over here, but nobody said we were sane about it all. LOL.

 

[Rex]

To be honest I never use the Noisegate with the Axe Fx so another thing I need to learn anyway. LOL.

Whoa. Definitely try that first. It's effective and kind to your signal, and it costs you nothing.

 

[Lkdog]

OK, last comment for now.
Looking at the Ebtech Hum X versus their other devices, I think I will try one of their Hum Eliminators which is a little better technology I think and uses 1:1 isolation transformers.

 

[Rex]

OK, last comment for now.
Looking at the Ebtech Hum X versus their other devices, I think I will try one of their Hum Eliminators which is a little better technology I think and uses 1:1 isolation transformers.

That would be my preferred choice over the Hum X. You're not taking any risks with power.

 

[Lkdog]

That would be my preferred choice over the Hum X. You're not taking any risks with power.

Rex- Thanks for your help with all of this.

I did some reading about the HUM X and although most people have good results, it seems like there is some risk as you note.

The ISO transformer option should work just as well I hope, as I think I have the specific trouble connection identified.

Will report back.

Thanks everybody. .

 

[Kceovaisnt]

Ground lifts can be safe if used correctly. But they can be dangerous if you isolate the device from ground entirely. The purpose of a lift there is to eliminate ground loops which means powered equipment in the signal chain is grounded at more than one point. You want your powered devices grounded at only one point.

I see you have used 2 humbuster cables but have left the third connection standard. Perhaps you should try the same for the connection from the FX loop send to Input 2L. Also, you made sure to short ring to sleeve only on one side correct? If so, you connect the shorted sides to your amp and not the fractal right? Not trying to sound condescending but often times when things seem this complex, I've missed something so simple.

 

[Rex]

Ground lifts can be safe if used correctly. But they can be dangerous if you isolate the device from ground entirely.

The only safe way to use a ground lift is on the signal, not on the power.

I see you have used 2 humbuster cables but have left the third connection standard. Perhaps you should try the same for the connection from the FX loop send to Input 2L.

Humbuster cables are only effective on Fractal outputs. They won't improve anything when used at the inputs.

 

[Lkdog]

Ground lifts can be safe if used correctly. But they can be dangerous if you isolate the device from ground entirely. The purpose of a lift there is to eliminate ground loops which means powered equipment in the signal chain is grounded at more than one point. You want your powered devices grounded at only one point.

I see you have used 2 humbuster cables but have left the third connection standard. Perhaps you should try the same for the connection from the FX loop send to Input 2L. Also, you made sure to short ring to sleeve only on one side correct? If so, you connect the shorted sides to your amp and not the fractal right? Not trying to sound condescending but often times when things seem this complex, I've missed something so simple.

All good things to double check.
I put tape on the ends I converted into TS connectors to be sure I didn't screw it up!!
They did reduce HISS noticeably. The hum remains. Persistent little devil.

 

[BillyZeppa]

All good things to double check.
I put tape on the ends I converted into TS connectors to be sure I didn't screw it up!!
They did reduce HISS noticeably. The hum remains. Persistent little devil.

Maybe it's a local power/ground issue... Does this problem persist in more than one place/building?

 

[Rex]

I put tape on the ends I converted into TS connectors to be sure I didn't screw it up!!
They did reduce HISS noticeably. The hum remains. Persistent little devil.

Weird. Humbuster cables can reduce hum and radiated interference, but they won't do anything for hiss. I wonder what else changed when you swapped in the cables.

 

[Lkdog]

Weird. Humbuster cables can reduce hum and radiated interference, but they won't do anything for hiss. I wonder what else changed when you swapped in the cables.

I stand corrected.

I still have some slight hiss on the amp's High Gain channel which is resolved by doing the BOOST/PAD thing on Output 2 to 12db or 18 db.

The hiss was just on the highest gain setting on the 3rd channel channel on the amp.
No hiss really on Clean or second moderate gain channel.

I am sure it would not hurt to replace the preamp and power tubes also in the amp, but that is not the source of the hum.