MR Soundboard voltage/amperage question...

[Sohryu76]

According to a thread on another board, the MR sound board take excess voltage supplied and increase the amperage going to the LED, which in some cases can cause a pretty good over drive, and possibly a burn out...
I was wondering if everyone who hooks up an MR soundboard to drive the LED directly always had success? I see that Tim's tutorials for the fx conversions just show the LED being wired with the 4.5 / 3.6 volt battery holder in place...
my question is:
does this always work ok?
If i'm going to go with a 4 AAA battery pack, would a buckpuck be helpful for managing the amperage?
anyone have any idea what I am talking about?

[morpheus1977]

I have been using a lux III red wired to a MR Vader for over a year now with no problems not using a buck puck or anything like that.

[Sohryu76]

I have been using a lux III red wired to a MR Vader for over a year now with no problems not using a buck puck or anything like that.

how many volts are you running through it? out of curiosity

[morpheus1977]

well a 4 AAA pack will give you 6 volts how the board distrubutes(sp?) that I dont know. All I know is 6 volts is the MAX you want to put on a MR board.

[Lord Dottore Matto]

I drive all MR boards at 6V (either 4 alkalines or 7.2V Li-ions with a 6V regulator). They put out roughly 1A (sometimes more) to the LED and I have not lost one in over 3 years.

[Novastar]

Right, the FX board is not current-regulating; it spits out more current as it gets more voltage.

However, yup--as you'll see in many posts here @ TCSS... 6v is just about the maximum you could give it without destroying the board upon power up. 7.2v is known to kill it (although what LDM is doing with the regulator is perfectly fine since the board never "sees" 7.2v)... and some hapless fools in the past have given the board 9v, which you can probably understand the result without me saying so.

6v on an FX will give @1A
5v on an FX will give @950mA
4.5v on an FX (like the standard/stock packs) will give @900mA

Those numbers are just estimates... they do not reflect exact values, and with the chosen few FX boards I've used... each board appeared to be different (big surprise). I had one which was spitting out just under 1A while on a 3.7v Li-Ion (???!?!?), and some other one that was only doing 820mA or something. Hard to recall. Besides, this was told to me by an assistant with a meter... at the time--I did not know how to meter for current.

[Onli-Won Kanomi]

MR boards can't handle more than 6V so how did the older MR LED sabers that used 6 cell battery packs which with alkalines would be 9V...was there a 5-6V regulator that kept them from frying the boards?

[Lord Dottore Matto]

MR boards can't handle more than 6V so how did the older MR LED sabers that used 6 cell battery packs which with alkalines would be 9V...was there a 5-6V regulator that kept them from frying the boards?

it was split into 2 4.5V circuits

[morpheus1977]

If I remember reading from another thread when MR first did the sabers they were EL which required 9v once they started doing the string they only needed half of that but were to lazy to design a new battery holder so they just split the current. Which made it last longer if I remember correctly.

[Novastar]

Right Morpheus, if you have essentially 3AA + 3AA set up to take advantages of the current... you double the runtime.

So for everyone not following along, it's just like:

Li-Ion 3.7v @ 2400mAh +
Li-Ion 3.7v @ 2400mAh =
--------------------------
Li-Ion 3.7v @ 4800mAh

But:

Li-Ion 3.7v @ 2400mAh +
Li-Ion 3.7v @ 2400mAh =
--------------------------
Li-Ion 7.2v @ 2400mAh

...if you wire for the voltage! Parallel / serial.