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uclaros

Midibox power consumption...

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Hi all!

I've built one more mios powered board to controll the channel - switching of a diy preamp.

My question is how much current will it draw?

I need to know for the specs of my toroidal transformer.

The setup consists of a Core,a Dout controlling 4 relais, that controll 4 leds and 10 H11F2 optocouplers.

No lcd.

All that getting power from a 15Volt tap on a toroidal.

Do you think I may have problems to use the same tap on the transformer that the tubes are using for heaters?

Any thoughts welcome!

Thanks in advance!

uclaros

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Hey,

Not sure on the ps q but I hope you can make your mbhp source selector available for others to use too! How about a schemo and some code?  ;)

Best,

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Hi,

I think you could get in trouble using the heater circuit for other applications:

The pre-heating of the tubes (I think it was 6,3 V ??) emittes through all tubes. So you have to take care that no noise (you will have digital noise) goes through the tubes.

I don't know much about the newest  tube-circuits. But in older circuits you always had noise problems with the heat-cables (Thats  why they were drilled and routed seperately).

Do you really have 15V for the pre-heat or do you speak of different taps ?

If you have only 6,3 V ~ for the heating you'll have another problem to get 5V = out of it: the voltage is too low.

The overall power consumption is not very high but depends mostly on the 4 relais. What are the current values of those coils ?

Do you know more about the 15V tap ? How many current can it drive ?

Just an idea: You can use a DC/DC coupler (is it the right word in english?) for the midibox (But you must know then how much current your circuit needs. The couplers greater than 3W are relative expensive). Benefits: Absolutely no coupling between the circuits.

greets

Doc

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Thanks for feedback!

The heaters may run on 6.3 or 12.6V depending on wether you connect both heaters of each tube separetely.

I don't know too much about electronics, but I supposed that the digital noise wqould be a problem.

Yet, I will custom order the toroidal transformer, so i will order different windings for the 12.6V of the heaters and one more winding for the 15V of the relais.

As for the schematics, it is actually a Core board stripped from all connectors except DIN-DOUT MIDI and it has onboard a 74HC00 for midi through. And that board connects on the DOUT example of the MIDIO128 that uses a ULN chip to drive the relais. Code is going to be MIDIO128, and I hope it will need no mods.

I don't have specs for the relais, how much is a typical current for 12V relais?

Thanks,

uclaros

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