Topic: Questions about the Edirol R4 PRO power supply

[GroundHog420]

Hi! Thanks for the ideas and the offer! I am thinking I should have a go at doing this myself at this point, but I just wanted to be sure I would be getting the right parts, so I wouldn't sweat it out doing a shoddy soldering job, and then end up blowing up the unit anyway. I do need to just sit down and spend some time getting better at soldering, in any case, because I have other cables that would benefit from it.

It seems really weird, though, that Roland hasn't made those available as standalone cables. I mean, if I want to pick up another PSB-1U Power Supply for my Edirol R4, I see them around from time to time on ebay, Reverb, etc. But this particular cable doesn't even seem to have a name. And as others have pointed out in various other threads, Roland seems to be pretty good at social distancing when someone needs support.

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i dont understand why you dont simply purchase a 4pin female xlr neutrix connector, and then cut the end off the ac adaptor listed.  if you want more flexibility , buy 3 xlr's (2 female and one male) and then put those in-line with tthe ac adaptor.

if you get the parts, i'd be glad to solder it for you.  i'm in central VA, certainly no pro, but have crossed this bridge before when wiring 4pin xlrs to our 12v sla's or the lithium batt packs.

[TheJez]

Hi, and thanks for that - I've been researching a bit, and It does seem like *some* extra power would be okay; I was just trying to determine if there's a point at which it might end up being too much

You really don’t need to worry about a power supply being able to supply too much. If your device needs 2 amps, your power supply need to be able to provide at least 2 amps. It’s ok if it COULD supply 5A, 10A or 1000A, as it will only provide the current the device will draw from it. It’s not like the power supply is pushing the current through the device!
So just make sure the voltage matches and that the power supply can provide sufficient current…

[Gutbucket]

Jez posted while I was typing, same answer as the others essentially..

Hi, and thanks for that - I've been researching a bit, and It does seem like *some* extra power would be okay; I was just trying to determine if there's a point at which it might end up being too much extra.

Using a  power supply with a higher amperage capacity will not cause a problem.  The recorder will just pull from it whatever current it needs.  A power supply that does not provide enough amperage IS likely to be problematic and should be avoided, but not an over-spec'd one.  Make sure the supply provides at least 2A, and as grawk mentions, make sure the voltage and polarity (how the connector is wired) are correct, and you should be good.  The range of amperages you mention finding above are all acceptable.


tl;dr- But what are the implications when taken to the extreme? If some kind of internal short failure were to occur inside the recorder, it would create a very low resistance circuit path which would in turn cause an unusually high current draw.  The power supply would then attempt to compensate and provide the additional current up to the limits of its capacity.  But since we are taking about well designed recording equipment, there is most likely an internal fuse in the recorder that is designed to blow in that kind of over-current situation, thus protecting the system and the user from catastrophic damage.  Short occurs, current draw rises, fuse heats up and blows.  That sequence occurs with any external supply of sufficient current capacity.  But lets rig the situation and take things to a ridiculous extreme. Say someone bypasses the fuse and is using a power supply with absolutely massive amperage reserves.  The recorder works just fine until that internal short occurs, but lacking the protective action of the fuse, current across the short-circuit  is no longer limited.  The power supply does its job and provides as much current as it has available, essentially creating an arc welder.  So, best not to bypass fuses or use welder-sized power supplies when unnecessary.

[GroundHog420]

Thanks again for all this info! This is all making sense to me, and trust me - I've been doing a lot of independent research into the same areas discussed here, so I fell like I am actually learning from this discussion, and not just asking folks to solve my problems for me.

The only other question I have is: why is the Power Supply listed as: (9–16 V)?

The battery (DC) power is clearly 12V, so that's why I've been looking for a connector rated at 12V. But can anyone explain why is there such a range, from 9V - 16V?

[Gutbucket]

Just makes selection of an external power supply easier since you aren't limited to using a supply that's specifically 12V or whatever.  Nice when powering several things like a recorder and preamp or whatever from a single USB battery that has both 12V and 9V outputs for instance.

[GroundHog420]

Sure, that makes sense - thanks again!

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Just makes selection of an external power supply easier since you aren't limited to using a supply that's specifically 12V or whatever.  Nice when powering several things like a recorder and preamp or whatever from a single USB battery that has both 12V and 9V outputs for instance.