Topic: Can Someone Fix a VRbox?

[Gr8ful98]

Here's what I'm looking for, and since I'm not good with soldering, or do it yourself stuff, I figured I'd ask y'all...a VR box to power both UA5 and JB3 simultaneously.  I know the ole UA5>JB3 combo is a dinosaur now & most folks have an "all in one" box. But....here's what I'm looking for: 

Primary power from a "Wally World" Batt is 9V, but a JB3 runs on 5V. If you went directly in with 9V, you'd fry the JB3. Thats where the VR box comes in. The VR is for "voltage regulator", which regulates the 9V down to 5V for the JB3. The other plug passes the voltage straight through, at whatever voltage the battery is. In this case, 9V, which is what the UA-5 takes. So to recap, it gives two output plugs, one regulated down to 5v (for the jb3) and the other at whatever input the battery is giving it (9v for the UA-5)

Could it have 2 inputs for the 9v battery...that way if I need to swap batteries I don't hafta power down everything.

Any of y'all DIY guys out there willing to help me out?  What would something like that cost?
It would be a great asset for going to festivals & such, I'm willing to pay for materials/labor & would be hella-grateful for such a device.

Thanks...

[willndmb]

what do you need power consumption for a vr box?

with my box i ran 4 different devices
as long as you had the correct cable you were golden
and a 9v walmart will run a ua5 and jb3 at the same time for 5 hrs or so

yes it is poss to have 2 plugs for batteries too
just make sure its wired to hot swap and not to double the power or you will fry the ua5
also make sure the ua5 cable has the tip set correctly, negative i recall

[Gr8ful98]

WOW....lot's of information!  Good to see folks here are not only helpful but knowledgeable too.

I bought the gear used, so I don't have the manuals. 
I did a little online searching & this is what I found:

Please let me know if this helps. 

UA5:

http://www.roland.com/products/en/UA-5/specs.html
from this link, there is a link to the owners manual too.

JB3 specs:

http://www.taperssection.com/index.php?board=14;action=display;threadid=16338

click on this link & scroll down to sections [150] [155] and [160] for info

[Gr8ful98]

PM sent to "mshilarious"   

[willndmb]

what do you need power consumption for a vr box?

Because it's questionable whether a linear regulator or DC converter circuit is more efficient.  The linear regulator will be no better than 55% efficient (5V/9V), which is quite a lot of power (and thus heat) to throw away if the current is high.  A DC converter can be designed at 80% efficiency, but they have a certain amount of overhead (as do various types of linear regulators) that limits the efficiency at low current draws, and in any case can be most efficient if designed for a particular load.

The other consideration is the ratings of the parts themselves.  For example, a 7805 TO-220 regulator without a heatsink can only dissipate a little under 2W, and not too much more even with a heatsink. For a 4V drop, that's less than 0.5A.  If you need more power dissipation, there are other solutions.  Various DC converter solutions also have power dissipation limits, but since they are running much more efficiently, that is less of a problem.

If you need very little current, say less than 30mA, a 7805 is not a very good solution for a linear regulator because of its 4mA quiescent current, which decreases efficiency even further.  It's possible to use a simple transistor-buffered zener diode and have almost no wasted current.  I doubt the current is that low in this case, but there seems to be a belief here that a 78XX is a universal solution to all power regulation needs, and that is not the case.

While we're at it, we can limit the output of the 9V out such that any shenanigans don't fry connected gear . . .

If I'm getting paid to build something, I would prefer to do the best job I can.  For that, I need to know at least a ballpark for current.  The specs should be in the manual, I just figure the owner of the gear would have that laying around . . .

learned something new
+t

[Gr8ful98]

Hey guys...

Thanks to the helpful folks here I am in possession of a VR box, the "BUBLEBEE" one that LEEGEEDY made.   It is not working properly(possible input wire problem, according to the owner)

Does anyone know how to "diagnose" a problem with this box, and fix it? 
I am not an electrical engineer, in fact...I'm lucky to remember red=positive & black=negative most of the time.

If anyone has the skills to diag/fix this little VR box for me, please let me know...as it was sent to me pending payment as long as I can find someone to fix it.

Thanks 

[H₂O]

I would not mind taking a swing at this.  I have built numerous VR boxes myself.