Power Supply for Midiboxes

[Pearl]

Hi there ...

I got some questions about power supply of midiboxes.

I want to build a complex Midibox like shown at picture.

For this I want to use a central power supply. Is ist possible to do something like this?

If it is OK, how much has the current of the transformator to be for this? ( At pdf's I found that every Core-Module needs ~ 500mA and the MF-Module needs 1A, but in summery, I think it's too much)

I would calculate, that max. 70% of LEDs and MFs are used at the same time.

Could it be that the current is too much for one MidiBox,because I want to build and test moduls one by one? (Some years ago I destroyed a pcb while using a bigger transformator than the original.)

Thanx for any information

Bye Pearl

[TK.]

Hi Pearl,

I don't have so much experience with transformers, but the circuit looks good (well balanced). To the seperate supply for the displays: should go to the backlights only (draws 100mA and more), and not to the general +5V input of the displays (draws just only ca. 1mA). On this way you will not run into trouble with the polarities.

Motorfaders: 2 x LM317 have to be used for 16 faders due to the max rating of the LM317 (if you are using the original MF layout, you will do this anyhow). A power consumption of 1A per 8 faders is very common when you switch to a new song and all faders are moving to a new position.

"Current too much": yes, thats the other side.... I would recomment fuses (buy 10 or 20 at once!).

Best Regards, Thorsten.

[Pearl]

Thanx ...

Ok, at the beginning I'll take a small one. If it is too small at the end - no problem to change.

Wich kind of fuses are recommended?

- quick or slow (in german "flink oder träge")

Bye Pearl

[TK.]

I would prefer the slow one, so that peaks don't blow the fuse

Best Regards, Thorsten.

[jasper81]

make sure yur transformer can also deliver the power.. Most cheap transformers can't handle high currents