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jaeger28

MultiCore Cable to connect Jack and Cat5 simultaneously?

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Hiya all,

 

I wanna run my JTV59P with my Helix in parallel with

-the CAT5 cable connection for songs with custom tunings and modeling guitars

-the standard jack cable for the magnetic pickups

 

Is there a multicore cable that has both, the Cat5 and Audio Jack in one cable and both connectors at both ends?

I could do one myself but it would be bulky.

 

Reason why I wanna do this:

This way I always use the (better) Helix A/D Converters instead of the ones in the Variax.

 

If I only connect through CAT5 then the Magnetics will be converted to digital in the Variax, and it sounds less punchy and full to my ears than going with the guitar cable to the Helix and let that one do the A/D job.

If I only go through Audio Jack, then I have no power supply, no remote control and an extra A/D-D/A from Variax to Helix, wich means more time lag and unnecessary tone loss.

 

Thaaaanks

CJ

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Careful, the Line 6 instruments have a well-known exception to electronic circuit design practices that somehow stresses... something..  if you connect to both outputs.  They would explain the physics behind this, but then they'd have to kill you.

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Thanks. Is that mentioned in the manual or anywhere? I couldn't find any remark on this...?

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Thanks. Is that mentioned in the manual or anywhere? I couldn't find any remark on this...?

Just one of many mysterious no-no's that are frequently hinted at around here, absent any real explanation. Somehow the fate of the free world would hang in the balance should such sensitive info fall into the wrong hands...

 

This one is extra peculiar though, as in order to use the clunky USB dongle to connect to Workbench, you need to have the battery in, and a 1/4" cable connected along with the VDI in order for everything to work...so apparently it's OK for that process, but if both outputs are connected for any other purpose, the world might end.

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i thought his explanation was spot on... using dual outputs stresses the components...

yes you can... no you shouldn't...

 

he's not likely to get into the engineering side of things telling you what values what components would need to be replaced....

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i thought his explanation was spot on... using dual outputs stresses the components...

yes you can... no you shouldn't...

 

he's not likely to get into the engineering side of things telling you what values what components would need to be replaced....

If it's that risky, then perhaps that should have been something that they included in the documentation that comes with the guitar...otherwise you'd have to hang around here a lot to have any clue that it isn't a good idea.

 

And the "explanation" still doesn't address why its perfectly OK to connect both while fiddling around with the USB dongle.

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Well good I asked. Just got the Variax and love it. Not keen on needing to having it fixed soon.

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I've connected my JTV-69 and 89f like this before with no issues. You'll need a ground lift on the 1/4" jack output though, otherwise there'll be some interference.

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This one is extra peculiar though, as in order to use the clunky USB dongle to connect to Workbench, you need to have the battery in, and a 1/4" cable connected along with the VDI in order for everything to work...so apparently it's OK for that process, but if both outputs are connected for any other purpose, the world might end.

 

Well, in fairness they do not tell you to plug the other end of that 1/4" cable into anything.  I guess it's the brutal loading effect of a (typically) 100k ohm load on the analog output IC that would "stress" things. 

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....

And the "explanation" still doesn't address why its perfectly OK to connect both while fiddling around with the USB dongle.

I expect it's because the USB Workbench interface does not provide power to the JTV. That's why you need to activate the battery with the 1/4" jack. Also, I don't know if the interface carries the digital audio signal. It may just carry control and model definition data. Perhaps the potential problems arise when the internal circuitry is handling the analog audio output signal as well as the digital model/mags signal(s).

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The RJ-45 connector on the guitar carries power, MIDI signaling and a 2 channel audio bitstream in AES digital format (mag pickups + modeling output).  There's a little diagram floating around that explains the pinout.  I believe it was reverse engineered, since Line6 has a policy of saying essentially nothing about the low-level technical details.

 

I would tend to doubt that the programming interface knows or cares about the digital audio and obviously doesn't supply voltage.

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I expect it's because the USB Workbench interface does not provide power to the JTV. That's why you need to activate the battery with the 1/4" jack. Also, I don't know if the interface carries the digital audio signal. It may just carry control and model definition data. Perhaps the potential problems arise when the internal circuitry is handling the analog audio output signal as well as the digital model/mags signal(s).

I understand that the 1/4" needs to be connected to "turn on" the guitar...what is still a mystery however, is why it's OK to have wires hanging out of both outputs for one function, but not others. It's a moot point anyway, as I doubt the answer will be forthcoming. It's probably better that we don't know anyway...it might cause a polar shift, and then we'd all be screwed. ;)

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The reason that the usb dongle doesn't power the variax is that it would violate the USB spec because the Variax draws more than 500 mA.

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I understand that the 1/4" needs to be connected to "turn on" the guitar...what is still a mystery however, is why it's OK to have wires hanging out of both outputs for one function, but not others. It's a moot point anyway, as I doubt the answer will be forthcoming. It's probably better that we don't know anyway...it might cause a polar shift, and then we'd all be screwed. ;)

 

Mr. Sarkissian has essentially claimed that the loading effect of plugging the 1/4" cable into an effect box or amp will result in damage to circuit components if the RJ-45 connection is also being used.  But, consider for a moment that the RJ connector does not (according to the pinout that's been posted) even carry analog audio. So exactly what is being "additionally" loaded by using both outputs simultaneously (since they have no signals in common)? A mystery for the ages, no doubt.

 

One possible source of problems might arise in a situation where you were trying to power the guitar from both a stereo 1/4" plug and the RJ-45 interface (with, e.g. an HD500 on the far end).  But even then any circuit designer worth their salt would place a diode in series with at least one of the power sources to prevent one supply from "back feeding" the other. 

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I wonder if the potential failure issue only occurs when you have the battery in the guitar. So that power comes from both, battery and Helix and then maybe overloads components?

In that case, keeping the battery out while having both lines connected could offer an easy fix?

 

I ran a test again today and the magnetics definitely are much more dynamic and punchy through the audio connection - 123db dynamics in the Helix A/D definitely makes a difference.

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My understanding is the Varaix connection to the various Line 6 gizmo's via the CAT-5 provides power to the Varaix and somehow, connecting to the 1/4" during this will, after awhile, not at first, potentially burn the/a circuit out. Not at first so just because it works now doesn't mean it won't burn it out later. Connecting the JTV directly to your conmputer doesn NOT provide power to the JTV since the USB output doesn't have enough power. You then have to provide power to the JTV via a battery or the TRS 1/4" power supply thing. It is OK to connect to both the 1/4" and CAT 5 on the Variax that way. But, I've always gotten noises if I wanted to use the 1/4" to hear the Variax that way.

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