MP-1 Phantom Power

[rnolan]

Hey Mate, it's unlikely to be the foot switch, but it may be .  But if you have 9v from the adapter tip, then we need to look further, as it will be either the tip isn't making proper contact (most likely), or the foot switch regulator.   Now in 30 years of owning and using a MXC, it's never been and issue.  But MJMP has advised that they do "sometimes" fail.  But it's never been reported on here by anyone, so I was a little surprised when he told us that titbit.

[Chase42147]

Hey Mate, it's unlikely to be the foot switch, but it may be .  But if you have 9v from the adapter tip, then we need to look further, as it will be either the tip isn't making proper contact (most likely), or the foot switch regulator.   Now in 30 years of owning and using a MXC, it's never been and issue.  But MJMP has advised that they do "sometimes" fail.  But it's never been reported on here by anyone, so I was a little surprised when he told us that titbit.

Finally got around to checking it this weekend! It is putting out 9V, I wasn't totally sure about how to get a current reading but it doesn't seem to be putting out 2 amps (although I may have been using the wrong setting on the multimeter, it's got a lot of settings I don't know how to use) I guess the next step will be using contact cleaner on the jack, and then trying aluminum foil to see if it makes a better connection

[rnolan]

Or get the correct tip, sounds like that is the problem, is 5.5mm x 2.5mm ??  And I think 500mA is what you need, not 2 amps, that's closer to power amp territory, but you need 500mA minimum, more is fine.

I just measured one of my AC adapter tips, Outer = 5.43mm or 7/32", Inner 2.42mm or 3/32".
This probably equates to a 5.5mm x 2.5mm which is the common size.

Easiest approach (IMHO) is buy one of these (below) as they come with 7 tips and one of those will be 5.5 x 2.5 and work    If you go for the slim DC adapter (which I have in my live rigs), just make sure you go inner (tip) +ve when you insert the tip in cable socket.

DC - (9V DC Jaycar)
AC - (9V AC Jaycar)

[Harley Hexxe]

Hey Chase42147,

   If your multimeter has DCA settings, then you want to check that way, you are looking for 500mA DC. 2 Amps is 4 times the amount of current than the pedal can handle, so you don't want that unless you like to cook electronics.

  If a little bit of foil gets power to your pedal, then you know the inner connector is too large. You just need a "N" type barrel plug on the end of your adapter. It wouldn't be a good idea to keep using it that way as the connection would be intermittent, and that will cause problems.

   If that doesn't get power to your pedal, then you have a problem in the pedal.

Keep us posted

[Chase42147]

Or get the correct tip, sounds like that is the problem, is 5.5mm x 2.5mm ??  And I think 500mA is what you need, not 2 amps, that's closer to power amp territory, but you need 500mA minimum, more is fine.

I just measured one of my AC adapter tips, Outer = 5.43mm or 7/32", Inner 2.42mm or 3/32".
This probably equates to a 5.5mm x 2.5mm which is the common size.

Easiest approach (IMHO) is buy one of these (below) as they come with 7 tips and one of those will be 5.5 x 2.5 and work    If you go for the slim DC adapter (which I have in my live rigs), just make sure you go inner (tip) +ve when you insert the tip in cable socket.

DC - (9V DC Jaycar)
AC - (9V AC Jaycar)

I'm not sure what size mine is, I'll bring it in to work tomorrow and measure it with my calipers there. But yeah, I might try ordering one of those and putting it on anyway!

[Chase42147]

Hey Chase42147,

   If your multimeter has DCA settings, then you want to check that way, you are looking for 500mA DC. 2 Amps is 4 times the amount of current than the pedal can handle, so you don't want that unless you like to cook electronics.

  If a little bit of foil gets power to your pedal, then you know the inner connector is too large. You just need a "N" type barrel plug on the end of your adapter. It wouldn't be a good idea to keep using it that way as the connection would be intermittent, and that will cause problems.

   If that doesn't get power to your pedal, then you have a problem in the pedal.

Keep us posted

Ahh shit I really hope I'm wrong about the 2 amps then, otherwise I fried it... At least I didn't plug it into the preamp lol!

[Chase42147]

OK so I just remembered I had the adaptor in my car, I went and got it and it says 9V 2A... shit. I guess I fried the pedal. I didn't think it mattered, kinda thought it was like an effects pedal where you can plug it into any 9V DC output on a pedal power supply... Well now I know I guess

Edit: I also measured the tip. OD is 5.43mm and ID is 2.60mm. So with any luck, maybe it didn't even contact!

[rnolan]

Hey Chase42147, having an adapter with more power available doesn't mean the unit will use it and fry necessarily. The one I use for my studio rack (9 V AC link in prev post) is 9V AC 1000 mA (i.e. 1 amp)  Generally it just means there is more power (current) available if the unit needs it.  The unit (MXC) will just use what it needs. What doesn't work is if the adapter has less current (amps) than you need.  So you shouldn't have fried it.  Plugging into the back of the MP-1 just routs the power to two pins on the 7 pin midi cable, it doesn't interact or affect the MP-1, so don't stress that one.

MMm, 5.43 / 2.60 sounds like close to the right tip size (i.e. 5.5 / 2.5). Albeit you'd probably prefer the inner to be slightly smaller rather than larger e.g. my tip measured 5.43 / 2.42.  So the middle prong of the socket should be 2.5, maybe 2.6 is just not quite making contact.  But that's (2.6) not a "common" size (from what I've read).  So maybe more a manufacturing tolerance thing I suspect??.  If you push (gently) on the plug while it's inserted (so it's ever so slightly at an angle), you may be able to get it to make contact , just to prove (or not) if it's the pedal that's the problem.  You can also try plugging the adapter into the MP-1 and use the 7 pin midi lead, it may? contact better that way?? worth a try and it wont hurt the MP-1.

[Chase42147]

Hey Chase42147, having an adapter with more power available doesn't mean the unit will use it and fry necessarily. The one I use for my studio rack (9 V AC link in prev post) is 9V AC 1000 mA (i.e. 1 amp)  Generally it just means there is more power (current) available if the unit needs it.  The unit (MXC) will just use what it needs. What doesn't work is if the adapter has less current (amps) than you need.  So you shouldn't have fried it.  Plugging into the back of the MP-1 just routs the power to two pins on the 7 pin midi cable, it doesn't interact or affect the MP-1, so don't stress that one.

MMm, 5.43 / 2.60 sounds like close to the right tip size (i.e. 5.5 / 2.5). Albeit you'd probably prefer the inner to be slightly smaller rather than larger e.g. my tip measured 5.43 / 2.42.  So the middle prong of the socket should be 2.5, maybe 2.6 is just not quite making contact.  But that's (2.6) not a "common" size (from what I've read).  So maybe more a manufacturing tolerance thing I suspect??.  If you push (gently) on the plug while it's inserted (so it's ever so slightly at an angle), you may be able to get it to make contact , just to prove (or not) if it's the pedal that's the problem.  You can also try plugging the adapter into the MP-1 and use the 7 pin midi lead, it may? contact better that way?? worth a try and it wont hurt the MP-1.

Ok good, that's a relief that I didn't wreck it! And that's good to know it wouldn't interact with the preamp itself (using phantom power) I was a little nervous about that. My co-worker pointed out today I could just bend the contact pins in, I didn't think of that. So I bent them further in, I'll try plugging it in again tomorrow!

[Chase42147]

Well I plugged it in... nothing lol

[rnolan]

Well that's a bummer, maybe it is the pedal?  Can you get any info from the seller?

[rnolan]

When you say bend the contact pins in, how do you mean?  You cant (as far as I can see) change the adapter tip.  And the socket (in the pedal) has a fixed centre (which was where, when you measured) was smaller than the tip centre.  You could try using your multimeter leads and another pair of hands to touch them on the contacts at both ends.

Alternatively, open up the pedal, check the socket (it may be damaged?) and connect directly to the leads (whatever) on the other side of the socket.

A totally different approach, buy a Behringer FCB1010, they don't phantom power (but can be modded to) and use that for switching.  Seems they go for around $250 AUD these days.

[Chase42147]

When you say bend the contact pins in, how do you mean?  You cant (as far as I can see) change the adapter tip.  And the socket (in the pedal) has a fixed centre (which was where, when you measured) was smaller than the tip centre.  You could try using your multimeter leads and another pair of hands to touch them on the contacts at both ends.

Alternatively, open up the pedal, check the socket (it may be damaged?) and connect directly to the leads (whatever) on the other side of the socket.

A totally different approach, buy a Behringer FCB1010, they don't phantom power (but can be modded to) and use that for switching.  Seems they go for around $250 AUD these days.

On the adaptor I bought, the inside contact is sort of a "U" shaped piece of metal, and I bent the legs of the U in.

Ya I'll open it up this weekend, but yeah if I can't visibly see a problem I'll probably buy the Behringer (really great price, I found them at Long and Mcquade for $165 CAD) otherwise I'll control it with a Boss ES-5 for now

[rnolan]

That's a strange tip contact setup  .  All the tips I have, it's a cylinder in the centre which I think the centre hole tapers slightly smaller as it goes in. Like the centre of the tips in this pic Wall Wart

[Chase42147]

Ohh yeah that would make more sense, that does seem like a better system