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newbie power supply question


drumwide
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Please excuse me if i have posted in the wrong thread.

I need to know if i can use one power supply for :

2 x core module

2 x motor fader module

4 x digital in module

4 x digital out module

1 x ltc module

this will be my nuendo controller I hope? I think this is possible, but I am new to elctronic circuits and don't want to zap my modules. ???

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Yes, one power supply will be OK. Using a regulator on each board will be OK too. (makes construction simpler)

1 amp should be enough, or 1.5amp just to make sure.

my many mistakes have proven the components in these circuits to be very tough!!

not sure about nuendo... it would be great if it supports the housten controller..??

note that if you are a begginer, it may take several weeks, or more, you will need a lot of patience, its not a quick project to save some money, but it is fun customising something for your own needs!!

good luck, from Steve

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I cant thank you enough for responding to my questions.

I will use a regulator on each module to be sure.

Nuendo(1.62) does support Steinberg's Houston and the mackie control among others.

I would like to be ablet o control 12-16 channels at once instead of 8 or 9.That is the great thing about this project.

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Anything around 12 - 15 volts would be fine. Even up to 18 volts is ok. The 7805 regulator is rated to higher than that but I don't like to push my luck ;)

Make sure you include the bridge rectifiers in your modules too.

It saves for incorrect polarity connection so you don't blow anything up at the start. :o

have fun ;D

Ian

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Errrr....

Sorry, but Ive gotta another opinion: ???

Yes, one power supply is certainly OK. The LCD backlight uses up the most power (about 150-250 mA - as bright as you want it).

BUT: As the 7805 only takes up to 1 A at all, its absolutely not neccesary to get a 1,5 A supply. 1 A is absolutely OK.

If you put in 12-18 V into the 7805 youve got some pretty nice heater. Damn hot heater to be exact.

I would go down to 7-10V as TK said. Thats absolutely enough. Going to higher voltages will only make the 7805 hotter and shutting down.

IF you use 12-18 V supply (I think you need it for the motorfaders) use a 7809 before the 7805 to get the voltage down and for heavens sake use a heat sink.

Hope I got nothing wrong there. :P

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thanks payc you have been most helpful.

I did not know you can do voltage drops from 7809 to 7805, but then again I am very new to this.

I have bought a 12.6 volt, 1.2 A transformer.

Is there some other circuitry I need between the secondary side of the transformer and the 7809?

If so I think I will take the transformer back and buy a regular power supply. ;D

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Yep, you would need nearly the same circuit as it is used on the Core PCB.

Meaning filtering everything again with caps and so on. By putting in the normal transformer voltage to the 7809 without anything else you have a nice candle again...  ;D

candle and heater... nice ...

OK, without fun: Thats because the out of the transformer also has negative potentials, what again the 7809 cant work out good.

What I would recommend is get a regulated power supply at 7-10 V and about 500-1000 mA (I would stick to the 1000 cause of the motorfaders).

btw: Thnx for the "Thnxs"  ;D

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This is an interesting thread that should not be dropped yet.  Most everyone understands that their Mega-Boxes have exacting power supply needs, but it seems few of us understand how to acheive the correct amounts.

It seems you definitely should not need one power supply per core.  Theoretically, how would you power four cores from one power supply?  

Does anyone know of a site for simplified explanations of power supply issues?  Determining power supply needs?

I'll stop here for now.

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Hey...

As i understand a full featured MBLC/MC will require >1A, here's the PSU i'll be making for mine:

mblc_psu.gif

Theoretically, how would you power four cores from one power supply?

Yes, from core info text:

J2 : +5V output, can be used to supply other core modules in a multiprocessor environment, so that you only have to mount the parts for the power supply (X1, IC3, C5, C6) on one core module. Restriction: the 7805 gets very hot when it delivers currents above 500 mA, so only core modules without backlit display like MIDIO128, MIDImerger, MIDIfilter should be supplied over this port.

For my quad SID i'm using one wallplug (15V 750mA) to power the lot (4 cores, 4 sids, lcd ...) i've 2 cores with the psu components stuffed feeding the other 2 cores (from J2) without the psu components stuffed, i originally just had one core with the 7805 etc stuffed and the other 3 without - but it got very hot, still gets hot now but all is workin fine...;)

Best...

Dan

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@d2k: Damn, youre all living in cold places, dont you?  ;D

Thnx for the picture!

@basta: Just take the power out of the main core (the two connectors in the upper left of the PCB) and connect them to the other cores. The other cores then dont need the bridge recitifier, the caps directly before and after the 7805 (I *think* 3 smaller ones and the big one) and the 7805 itself, they dont have any use anymore. But this time you have to take care about the polarity.

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  • 2 weeks later...

For instance, 16 Motorfaders could use up to 2 Amps if driving all faders simultaneously.  Is this right?  But a power supply (12v 2A, for instance) would be too hot for the 7805.

How are people with more than one MF module powering their devices?

Am I the only one that doesn't understand this?

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Hey Basta!

 haven't seen you 'round for a bit. You gettin more mf's soon? Hey, I can give that spare one back to you if you want it to check out your circuits....

 The power for the mf's comes regulated by the LM317, not the 7805, so 7805 will be fine.

 A beefier power supply will be ok, e.g 2A, (sorry Ian) as the circuit will only draw the current that it needs. try your 1.2A supply with 8 mf's first, before seeing if it will power 16 of them.

 The regulator will only get cooked if the circuit draws more than it is designed for, but connecting a bigger supply (e.g 2A) to it is ok.  Just because a supply is rated at 2A dosen't mean it will supply 2A all the time, it only supplies what the load is drawing. (I wrote a good explanation on this in another post somewhere)

 I would use a LM317 regulator on each mf board

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huuumm...

the best way to make a good power supply : take a transformer, put the caps and the regulator (maybe 78S05CV is better because it can output 2A) for +5V regulated, and then plug it on J2 connector of each core.. and on the core you don't need the 7805, the diode bridge, and caps C5, C6, C4... so you make a big power supply for all the midibox!

if you want to make it better, take a 2x8V transformer and make a double regulated +5V (with 78S05CV you get so +5V@ 4A).

For the MF module : it's the same, but there you can keep the original schemtic and just plug a 12V transformer.

Try to avoid using of multiple regulator, for exemple transformer -> 7812 -> 7805, you lost power in heat !

I think you can also use a AT power supply, wich is better , but you just have +5V and +12V, maybe not enough for MF...

I'm going to make a schematic of a complete power supply for the midibox LC, but I don't konw where to find a transformer with 2x8V and 12V...

Don't forget that if the inpur voltage of the regulator is too high, you will loose power! for example, for the 7805 the max in put voltage is 12V! it must be at least 8V.

Take a 8V transformer, with rectified bridge and caps, you get 8V*sqrt(2) on the output so 11.3V which is good for 7805.

I hope this can help!

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huuummm I've got some trouble understanding what you mean, but if you mean that there's no "transformer" in AT power supply, it's true... I don't know the English word for that... the efficiency is far better than a "classical" power supply... but harder to build due to the coil... So it's smaller, and less heavy!

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Switchers are way more efficient, but introduce a lot of noise and ripple into the power, bad for anything analog (like reading potentiometers or moving faders around).

Linear supplies work like a battery, the only noise/ripple you get is what you introduce with the load.

Have fun!

SmashTV

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Well, here's my plan.  A combination LC/XT box with a 12V 2A power supply, and a heatsink on the 7805, and on the LM317's just for kicks.  

I also found an old tabletop-type adapter from an old laptop that I might use.  18v @ 4A, but I'll wait on that until I'm convinced it won't burn down the apartment.  Aparently, I'm banned from causing electrical fires.

Hey Steve!  That LC of yours is coming along nicely.  Mine is still in the wings, but I can't imagine I'll sit on it for too long.

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hey A,

 if you are going to use that 18V 4A, check the voltage is what it says it is! My 12v1.6A PSU is really 16V! So I put an extra LM317 before the 7805, dropping it down to 10V, so as not to cook the 7805. (Would have used a 7812 instead, but I didn't have a spare)

 I also tried out my 10A supply today, just for jokes! the faders seemed a bit smoother, even speed, but I think the PS is noisier electrically, (it looks like maybe 30 or more years old!!!!) as I got a bit of jitter. (I went back to the 1.6A)

 im tired sllepy and should be asleep. Im ging now!!!

yeah I m happy now awith my LC! ;D tHANDKS TK AND ALL!

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