MIDIbox CV - do i need a psu?

MIDIfication
1

Hi,

do i need a psu or is the one of the core module enough and i only need a transformer? How many VA does it need to have ?

2

hi,

you need a 2*12V PSU to power the Aout module. 

3

thanks

so for the core-module, a 9V, 556mA transformer is ok, and for the aout_lcs ( http://ucapps.de/mbhp/mbhp_opl3_psu.pdf ) i need 2*12V with at least 100mA per wiring, right?

by the way do you know whether there’s a reason the resistors are coal-types? because as far as i can see metal-film types are both better and cheaper…

4

The 1% tolerance resistors you would want are usually more expensive… Maybe you found a good deal :slight_smile:

The cheaper resistors are 5% and they’re not really accurate enough for the aout module…

5

thanks, i wish i had, it’s just reichelt has stupidly increased the prices for the 5% ones from i think 2c to 10c per unit :-\

i was still tiping the order for the core, but i thought it would be stupid to pay more for lesser quality ones if there was no reason…

for the aout i will get some bags of 100 resistors from conrad and measure…

by the way, is it the exact value that counts or the fact they are as near as possible to one another ?

6

by the way, is it the exact value that counts or the fact they are as near as possible to one another ?

Both in this case… The value will control the range of voltages output, and the tolerance the accuracy of the different levels.

7

for the aout i will get some bags of 100 resistors from conrad and measure…

try www.pollin.de

they’re cheaper than reichelt and conrad.

8

thanks  :slight_smile:

i didn’t find normal 1% resistors at pollin. in this particular case conrad seems to be the cheapest one, you pay 1,76 for a package of a hundred resistors, and i think i’ll take 10 of them to be able to choose (unless it’s stupid to take so many for 4 aout_lc bords), so it will be 1,56 per pack. i’ll probably also take precison trimmers instead of the normal ones.

EDIT:

i just thought: it probably is _very_ stupid to take so many, for the hours it would take to go through them…