Phantom Blockers and Helix outs?

[pipelineaudio]

Probably not actually anything to do with helix, but who knows.

I've got one of these Triton Phantom Blockers on my Helix 1/4" out. I have an adapter cable from the helix 1/4" out wired tip to XLR 2, ring to XLR 3, Sleeve to XLR 1. This cable is then plugged into the phantom blocker

If I run the phantom blocker to a regular XLR cable into an XLR input on a PA monitor or whatever, all is right with the world and it works fine.

If I run that regular XLR cable into a balanced XLR female to balanced 1/4" TRS adapter cable into an unbalanced 1/4" TS input, everything works fine as it should

If I run that regular XLR cable into a balanced XLR female to unbalanced 1/4" TS adapter cable wired pin 2 to tip and pin 1 and 3 to the sleeve into an unbalanced 1/4" TS input, I get nothing.

If I make an adapter cable from the helix 1/4" out using a 1/4" unblanced TS wired tip to XLR 2, sleeve to XLR 3 and XLR 1 and then plug this cable into the phantom blocker, I get nothing no matter what sort of cable or input I plug it into from there.

Edit for clarity: If I make an adapter cable from the helix 1/4" out using a 1/4" unblanced TS wired tip to XLR 2, sleeve to XLR 3 and XLR 1 and DON'T plug this cable into the phantom blocker, it works fine.

What in the world is this phantom blocker doing?

If I run without the blocker, if phantom power is present it makes distorted hell of bloody death

 

[jay mitchell]

Probably not actually anything to do with helix,

IMO it probably does.

I've got one of these Triton Phantom Blockers on my Helix 1/4" out. I have an adapter cable from the helix 1/4" out wired tip to XLR 2, ring to XLR 3, Sleeve to XLR 1. This cable is then plugged into the phantom blocker

So far, so good.

If I run the phantom blocker to a regular XLR cable into an XLR input on a PA monitor or whatever, all is right with the world and it works fine.

Of course. That's a one-for-one connection of input to output.

If I run that regular XLR cable into a balanced XLR female to balanced 1/4" TRS adapter cable into an unbalanced 1/4" TS input, everything works fine as it should

Yup. Pins 1 and 2 are connected one-to-one, and Pin 3 of the XLR (ring on the 1/4" end") is unterminated (floating). That's because the input of the downstream device doesn't short Pin 3 to ground. See below.

If I run that regular XLR cable into a balanced XLR female to unbalanced 1/4" TS adapter cable wired pin 2 to tip and pin 1 and 3 to the sleeve into an unbalanced 1/4" TS input, I get nothing.

The Helix apparently does not play well with one leg of a balanced output shorted to ground. That's not particularly unusual.

If I make an adapter cable from the helix 1/4" out using a 1/4" unblanced TS wired tip to XLR 2, sleeve to XLR 3 and XLR 1 and then plug this cable into the phantom blocker, I get nothing no matter what sort of cable or input I plug it into from there.

That's because you're still shorting ring/Pin3 of the Helix output to ground.

What in the world is this phantom blocker doing?

It's just a balanced capacitive decoupling circuit with shunt resistors on both sides of the capacitors to bleed off any residual charge.

To avoid the problem, just don't short either side of the Helix' balanced outputs to ground. FYI, that is always best practice for any device with balanced outputs.

 

[DieSchmalle]

The Helix apparently does not play well with one leg of a balanced output shorted to ground. That's not particularly unusual.

The Helix' 1/4" OUTs aren't balanced AFAIK. *edit

 

[Alex Kenivel]

The Helix' 1/4" OUTs aren't balanced AFAIK.

They're impedance balanced

 

[DieSchmalle]

They're impedance balanced

Ok, thanks. My flawed "knowledge" comes from reading the manual.

Helix manual p.9
26. 1/4" OUT Use unbalanced 1/4" TS cables to connect to your guitar amp, "FRFR" speaker(s), studio monitors, or other playback system. When using a single amp
or speaker, connect only the LEFT/MONO 1/4" jack.

This probably is a recommendation then and not a spec. In any case the manual is not mentioning that the 1/4" OUTs are impedance balanced. @Digital Igloo

 

[jay mitchell]

The Helix' 1/4" OUTs aren't balanced AFAIK.

Were that the case, the ring of a 1/4" jack would not connect to anything in the Helix, and it would make no difference whether it was shorted to ground by a 1/4" TS jack. The OP makes it clear that shorting the ring to ground causes a problem.

 

[DieSchmalle]

Were that the case, the ring of a 1/4" jack would not connect to anything in the Helix, and it would make no difference whether it was shorted to ground by a 1/4" TS jack. The OP makes it clear that shorting the ring to ground causes a problem.

Which is why I scratched my head - wrong assumptions on my part.

 

[DieSchmalle]

Were that the case, the ring of a 1/4" jack would not connect to anything in the Helix, and it would make no difference whether it was shorted to ground by a 1/4" TS jack. The OP makes it clear that shorting the ring to ground causes a problem.

Isn't using a normal mono 1/4" cable doing the same with the 1/4" OUTs - shorting sleeve and ring? What am I missing here?

 

[Alex Kenivel]

Ok, thanks. My flawed "knowledge" comes from reading the manual.

This probably is a recommendation then and not a spec. In any case the manual is not mentioning that the 1/4" OUTs are impedance balanced. @Digital Igloo

I think first saw "official" word here: (added by "Guest" but edited by Line6Will)

Helix Floor/Rack/LT
Inputs

Guitar in: Auto impedance unbalanced TS, the impedance will be determined by the first block in the signal chain. (This is a setting that can be adjusted in Global Settings)
Aux In: 10k ohm unbalanced TS
Returns: 1Meg unbalanced TS (instrument mode)/10K unbalanced TS (line mode)

Outputs

L and R Main Out: Impedance-balanced TRS
Sends: Impedance-balanced TRS
Dry (Helix Rack only): Impedance-balanced TRS

HX Effects

L and R Main In: 1Meg unbalanced TS
L and R Main Out: Impedance-balanced TRS
Sends: Impedance-balanced TRS
Returns: 1Meg unbalanced TS (instrument mode)/10K unbalanced TS (line mode)

Note:
Although all the outputs use TRS jacks, they are not true balanced outputs. They are only impedance-balanced.

· A true balanced output would have the tip and ring driven with (out-of-phase) audio signal. The outputs on HX Effects are only driven on the tip.
· However, because they are impedance-balanced, you can still get some common-mode rejection of external noise sources (i.e. power line hum) if a TRS cable is used to connect the HX Effect outputs to a device with balanced inputs.
Edited August 16, 2018 by Line6Will

 

[DieSchmalle]

I think first saw "official" word here: (added by "Guest" but edited by Line6Will)

If you want to know what the thing you bought for serious money can do: search our web site for an obscure "Guest" post.
- Line6 (unoffically)

 

[jay mitchell]

Isn't using a normal mono 1/4" cable doing the same with the 1/4" OUTs - shorting sleeve and ring?

Yes. It is something of a puzzle, isn't it?

If the OP's description is correct and complete and if the Helix output is a simple unbalanced T/S type, then the fourth connection scheme in the OP would pass signal, as there would be no connection from anything in the Helix to the ring. Whatever is connected to the ring apparently does not like being shorted to ground.

Also, the definition of a balanced signal is that the impedance of both signal legs to ground is identical. The definition does not require symmetric signals. Common-mode rejection of EMI does not rely on symmetric signals to work.

Finally, if there is signal on the tip and the ring simply has a series resistor to ground (required to match the output impedance of the signal source on the tip), then shorting the ring to ground will not interfere with passing signal.

 

[pipelineaudio]

Interesting that they are impedance balanced....but what the symptoms seem to say is that the phantom blocker is flipping pin 2 and 3 or something else weird. Pin 3 to pin 1 shorted works fine if the phantom blocker isn't in the circuit.

If I can hook to an o-scope later, I will be able to see if there is signal on the ring and not the tip as it kind of seems like

 

[DieSchmalle]

Interesting that they are impedance balanced....but what the symptoms seem to say is that the phantom blocker is flipping pin 2 and 3 or something else weird.

Flipped pins would explain the matter. But it would be weird in a commercial product like that. Fun stuff.

 

[pipelineaudio]

No real info here: https://www.tritonaudio.com/phantom-blocker

I'll try floating pin 3 and see what happens in the adapter cable

 

[pipelineaudio]

Floating pin 3 still does NOT pass signal! Doing a live stream now on this

 

[pipelineaudio]

WHOA! Signal hot is pin 2 at the input of the phantom blocker and pin 3 on the output! At least the way it measures on a scope!

 

[DieSchmalle]

WHOA! Signal hot is pin 2 at the input of the phantom blocker and pin 3 on the output! At least the way it measures on a scope!

Made in Holland

 

[pipelineaudio]

Stick to dykes I guess

 

[SwirlyMaple]

WHOA! Signal hot is pin 2 at the input of the phantom blocker and pin 3 on the output! At least the way it measures on a scope!

That’s how it blocks. It just shorts everything together

In all seriousness though, did you measure this without any other cables/adapters connected to it? Are you 100% sure it’s not a flipped pin somewhere else?

 

[pipelineaudio]

Yes. I actually did it by soldering and unsoldering pins so I could try each combination. If you sit thru the five years of live stream, you can even see where I hooked it to a tone generator with the tone output on pin 2 and the tone only comes out of the phantom blocker on pin 3