Phantom powering a Liquid Foot 12+ (WARNING)

Can we get a word from FAS on the current rating of the bead?

If I know the rating, I can easily measure the current consumption of the controller when using the adapter, and know if I can use the 7 pin or not...
 
well I'm using the old Jr. that is only 9v. I'm beginning to believe there is an issue with the part on the board, that or it's rating is not high enough.
 
It's not the voltage that matters here, it's the current. Jeff at LF believes that the ferrite bead used here has a 1A rating. So if you exceed 1A for any length of time, the bead will pop whether you're using 9V, 12V, or 20V.

I hope to talk to Fractal Support today, and believe me, I'll push hard to have this issue more proactively warned about, and also suggest that a more robust part might be the best solution in future build specs.

As for the cable, I wonder what gauge the wires are in the Rocktron cables? Length may matter, too, since the longer the lead is the less current capacity it has for a given gauge. I got a pair of 30' Rocktron cables cheap, and there's an advantage to using stock cables like this if possible: they're relatively cheap and readily available. But if it would be better to get a single, reliable but relatively expensive custom cable, it might be worth it. If the wires in the Rocktron are the typical 24 gauge like for data, I think that 1A exceeds the recommended ampacity for that wire. It'd be interesting to see what the voltage drop was at the controller end of the cable, to see how much current is being converted to heat over the length of the cable. But the Rocktron has molded ends, so...

Javajunkie, I'm curious what Best-Tronics cables you've used, and whether they have cable gauges associated?
 
fyi... my adapters were 9vac 1a or 1000ma. mine was a custom bestronics 25' cable with a 7 pin xlr on one end and a 7pin midi on the other. new one i made from bestronics cable, brand new xlr 7 pin, and 7pin midi.
 
dpeterson said:
fyi... my adapters were 9vac 1a or 1000ma. mine was a custom bestronics 25' cable with a 7 pin xlr on one end and a 7pin midi on the other. new one i made from bestronics cable, brand new xlr 7 pin, and 7pin midi.
Click to expand...

Any idea what gauge they are? Or if they doubled up leads on the power conductors? I have a vague recollection that MIDI doesn't use all 5 of the pins at the plug, so perhaps you could pair leads for the power conduction and still use a 5 or 7 conductor cable.
 
jon said:
Can we get a word from FAS on the current rating of the bead?

If I know the rating, I can easily measure the current consumption of the controller when using the adapter, and know if I can use the 7 pin or not...
Click to expand...



From Fractal:

"The phantom power jack is rated at 1A. If your pedal draws more than that you risk burning up the EMI suppression beads."
 
greiswig said:
It's not the voltage that matters here, it's the current. Jeff at LF believes that the ferrite bead used here has a 1A rating. So if you exceed 1A for any length of time, the bead will pop whether you're using 9V, 12V, or 20V.

I hope to talk to Fractal Support today, and believe me, I'll push hard to have this issue more proactively warned about, and also suggest that a more robust part might be the best solution in future build specs.

As for the cable, I wonder what gauge the wires are in the Rocktron cables? Length may matter, too, since the longer the lead is the less current capacity it has for a given gauge. I got a pair of 30' Rocktron cables cheap, and there's an advantage to using stock cables like this if possible: they're relatively cheap and readily available. But if it would be better to get a single, reliable but relatively expensive custom cable, it might be worth it. If the wires in the Rocktron are the typical 24 gauge like for data, I think that 1A exceeds the recommended ampacity for that wire. It'd be interesting to see what the voltage drop was at the controller end of the cable, to see how much current is being converted to heat over the length of the cable. But the Rocktron has molded ends, so...

Javajunkie, I'm curious what Best-Tronics cables you've used, and whether they have cable gauges associated?
Click to expand...

http://www.best-tronics.com/guitar-cable/MIDI/midi7.aspx
24 AWG

 
I'm using the exact same power supply that I used on my Ultra + FCB1010 as I am now using for my II + LFJr. Haven't had any problems, both using the same wall wart, but different MIDI cables.

FCB: Rocktron RDMH900 (7pin side at AFX, 5pin + dongle at FCB), wall wart plugged into Ultra (even used this combo a few times on the II)
LFJr: 7pin/7pin MIDI, same wall wart

Both have worked flawlessly except when my wall wart backs out from the plug in the power conditioner.
 
This is all good info, so thanks. I just got a LF 12+ from someone on this board. Fortunately the adapter isn't one that fits the Axe Fx II, so I didn't plug it in there. I'm going to talk with Jeff at FAMC tomorrow about some configuration issues, so I'm going to ask what he might recommend as a solution. The Rocktron or similar cable looks like the simplest thing.

PS. I had a LF Jr. that I used via adapter in the back and 7 pin midi and it worked fine. I think the current draw is a lot lower for that without all the pretty lit up windows.
 
javajunkie said:
From Fractal:

"The phantom power jack is rated at 1A. If your pedal draws more than that you risk burning up the EMI suppression beads."
Click to expand...

I got the same word, along with their expressed surprise that any board would require more current than an amp. That surprise helps me understand why they had not included this current limitation in their documents anywhere. I wonder what the RJM Mastermind might draw?
 
greiswig said:
I got the same word, along with their expressed surprise that any board would require more current than an amp. That surprise helps me understand why they had not included this current limitation in their documents anywhere. I wonder what the RJM Mastermind might draw?
Click to expand...

I don't know if one LF+ draws more than 1A, but when you run two with the expander mode it does.

Probably a lot - From their forum feature list:

"Due to the amount of current the GT requires, phantom power will be over the XLR connector only."
 
Regarding the cables, I'd remembered right: MIDI uses two conductors plus the shield. So I think even if you had only a 5-conductor cable with 24g wire, you could pair up on the power conductors and boost your current capacity while improving reliability.
 
UPDATE: I received a response back from Matt at FAS (passed this on to him yesterday). He has updated the manual to advise of the 1A limit on power pass through. One down... :)
 
Good news in a way. I hope they'll also come to regard this as an unnecessary limitation and might have future builds accommodate more current, too.
 
The 1a thing still doesnt explain my situation.. mine power supplies were only 1a, because that is what the LFJR required and my FX1 used as well, i dont own one with more amps. It also cant draw more than what the power supply produces. I'm assuming there is a tolerance on that part and if it's under and you hit it with one amp... pop. I'm going to guess that is what it was. Not a huge deal, I just spent the better part of a week figuring it out, rewiring my panel, and 3 power supplies. That part would also seem like a prime candidate for a replaceable fuse.

To be safe i wouldnt even use the phantom power on the axe2 at all. Make a custom cable.
 
greiswig said:
Good news in a way. I hope they'll also come to regard this as an unnecessary limitation and might have future builds accommodate more current, too.
Click to expand...
Agreed.

I would like to hear them weigh in on it and advise if there was a specific reason the phantom jack wasn't just hard wired to the midi pins as a pass through or if the bead is there to protect something.
 
Rick said:
Agreed.

I would like to hear them weigh in on it and advise if there was a specific reason the phantom jack wasn't just hard wired to the midi pins as a pass through or if the bead is there to protect something.
Click to expand...

In one email from support (not sure who), the writer stated that it was "for EMI compliance."
 
dpeterson said:
The 1a thing still doesnt explain my situation.. mine power supplies were only 1a, because that is what the LFJR required and my FX1 used as well, i dont own one with more amps. It also cant draw more than what the power supply produces. I'm assuming there is a tolerance on that part and if it's under and you hit it with one amp... pop. I'm going to guess that is what it was. Not a huge deal, I just spent the better part of a week figuring it out, rewiring my panel, and 3 power supplies. That part would also seem like a prime candidate for a replaceable fuse.

To be safe i wouldnt even use the phantom power on the axe2 at all. Make a custom cable.
Click to expand...

Dave, I'm not sure what happened in your case, but as I said before it sounds more like there was a short somewhere that was ruining the PS's. A situation like this design flaw can't realistically cause what you described, because by definition it "fails open." But I'm glad you got it figured out.
 
FYI I used Mogami tube mic cable to make my 7 pin midi cable, it's got 2x22AWG conductors, which is nice and thick for carrying decent current over a reasonable distance. The smaller wires can be used for the MIDI signals (both in and out). And the shield goes to the ground pin. It was a pain to solder, but it's given me no grief.
 
Interesting, Fret. Mogami makes good stuff! A pair of 24AWG wires ought to handle even more current than a single 22AWG wire, though.

I'm still trying to talk to FAS about a good solution for my individual unit to get it back in working order without voiding the warranty. Mouse has ferrite beads that will handle the current, but if they won't let me do the repair without voiding the warranty, I'm kinda screwed. I hope they stand behind this somehow!
 
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