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2 (noobish) Questions on mixer power supplies
Old 15th October 2013
  #1
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2 (noobish) Questions on mixer power supplies

1. Can i connect the PS to the main breaker switch that i use to turn on my entire gear collection?

2. Why does a power supply for a mixing console have to be so large?


About question 1:
The way i have set my gear up, everything in it is powered from just one wall outlet, so that i only have to flip one switch to see all the pretty lights start blinking.
All the gear is basically "on" all the time so that powering it on/off happens at the breaker.

So far none of my gear has complained about this, but is it any different with an old Soundcraft CPS 650?

What i am asking is wether there is some sort of powering up cycle that has to happen at the CPS power switch, or whether i can just keep it "on" and send it some power when i want the mixer turned on?



About question 2:
I just wonder why the PS is so huge compared to the PS of my 16:8:2 channel "Studiomaster" - which is just a nice little block about a quarter or a third of the size of the 650, which btw weighs in at appr. 13 Kg.

I mean, a mixer afaik doesn't have to deal with huge amplification or high voltages or anything, so why this massive transformer and stuff?

Is it because there are so many tiny amplifications going on so that the cumulative effect results in a lot of power draw?


Thx for any answers in advance
Old 15th October 2013
  #2
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Quote:
Originally Posted by grumphh View Post
1. Can i connect the PS to the main breaker switch that i use to turn on my entire gear collection?

2. Why does a power supply for a mixing console have to be so large?
Answers...

(1) Check how much power the supply draws. Then check the fuse rating on the PS to determine what type of current it expects to pull safely. Then check the current requirements for all of your other gear. Then check the maximum current rating for your specific line. Between all of that you will have your answer.

I personally don't like coming anywhere near to overloading any single power line because (a) it's not safe, and (b) it may lead to transient suppression. And don't forget to put a power conditioner in the line as well, meaning two conditioners if you find you need two lines. Leave out the conditioner and one day an intermittent power spike may take out some of your gear, at which point you will profusely curse and wish you previously had had enough sense to have put a conditioner in the line.

(2) High end professional recording consoles have power supplies that are overbuilt to allow them to instantaneously deliver high amounts of current to reproduce transients efficiently without loss of transient detail. Your large PS is built to handle the absolute peak power requirements which will occur for a mere fraction of a second. In other words your supply is overbuilt to ensure your supply will never sag in terms of voltage and current even for a moment under extreme transient conditions. Loss of transients make music sound dull and lifeless, and the purpose of an overbuilt supply is to ensure that the recorded musical product is capable of having all transients recorded in tact as they originally occurred.

To look at it another way, cheap equipment often uses small power supplies that can only handle the maximum RMS requirements of the overall program load without any extra power capability needed to reproduce large transients. The result is constricted sound.
Old 15th October 2013
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Quote:
Originally Posted by Frank_Case View Post
Answers...

(1) Check how much power the supply draws. Then check the fuse rating on the PS to determine what type of current it expects to pull safely. Then check the current requirements for all of your other gear. Then check the maximum current rating for your specific line. Between all of that you will have your answer.

I personally don't like coming anywhere near to overloading any single power line. Oh, and don't forget to put a power conditioner in the line as well, meaning two conditioners if you find you need two lines. Leave out the conditioner and one day an intermittent power spike may take out some of your gear, at which point you will profusely curse and wish you previously had had enough sense to have put a conditioner in the line.

(2) High end professional recording consoles have power supplies that are overbuilt to allow them to instantaneously deliver high amounts of power to reproduce transients efficiently without loss of transient detail. Your PS is built to handle the absolute peak power requirements which will occur for a mere fraction of a second. In other words your supply is overbuilt to ensure your supply will never sag in terms of voltage and current even for a moment under transient conditions. Loss of transients make music sound dull and lifeless, and the purpose of an overbuilt supply is to ensure that the recorded product is capable of sounding lively.

Cheap equipment usually have power supplies that are smaller because they are often built to only handle the average RMS requirements of the overall program load without any extra power capability to handle large transients.
Thx for the explanation of the necessity of a massive power supply.


As for power conditioners, i do really trust the engineers that work on the danish electrical infrastructure, and i think that we do have very stable power compared to the States.
At least all those horror stories about spikes and brownouts and all the other problems you seem to be plagued with are nothing i have ever heard about here.

But yes, i will have to check on the power draw of the PS - however, i assume that power draw depends on how many channels i have turned on at a time?

But there is no harm in switching the PS on from a breaker insted of on its faceplate?
Old 15th October 2013
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Quote:
Originally Posted by grumphh View Post
As for power conditioners, i do really trust the engineers that work on the danish electrical infrastructure, and i think that we do have very stable power compared to the States.
FOOLISH. Trust nobody. Transients can occur in the best of power grids.

Some common sources of transients:
(1) Lightning striking power lines.
(2) Industrial equipment turning on and off at local factories, sending reactive power back into the power grid that is out of phase with the incoming power generated by the utility. This reactivity is usually inductive and is often traced to large industrial motors of which there are many connected to the grid.
(3) Turning generators on and off at the power plant in a way in which they are not perfectly synced up in phase for a few seconds.


Quote:
But there is no harm in switching the PS on from a breaker insted of on its faceplate?
There usually is no difference, however there can be problems in isolated circumstances.

I recently came across a rare situation where individual equipment in the rack was blowing fuses when the entire rack would be turned on, but the fuses failed to blow when the equipment was turned on individually. The best explanation I could come up with was that the power transformers inside the equipment somehow inductively interacted with each other during start-up. Only equipment having their PS transformers in very close proximity to each other had the problem. I remedied the situation by rearranging the equipment in the rack in such a way that the transformers in the effected equipment were at a greater distance from each other.

And there can be inrush current problems, the most common being very large inrush current as inductors and capacitors within all the equipment connected charge simultaneously causing the main breaker for the line to blow.
Old 15th October 2013
  #5
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Quote:
Originally Posted by Frank_Case View Post
FOOLISH. Trust nobody. Transients can occur in the best of power grids.

Some common sources of transients:
(1) Lightning striking power lines.
(2) Industrial equipment turning on and off at local factories, sending reactive power back into the power grid that is out of phase with the incoming power generated by the utility. This reactivity is usually inductive and is often traced to large industrial motors of which there are many connected to the grid.
(3) Turning generators on and off at the power plant in a way in which they are not perfectly synced up in phase for a few seconds.




There usually is no difference, however there can be problems in isolated circumstances.

I recently came across a rare situation where individual equipment in the rack was blowing fuses when the entire rack would be turned on, but the fuses failed to blow when the equipment was turned on individually. The best explanation I could come up with was that the power transformers inside the equipment somehow inductively interacted with each other during start-up. Only equipment having their PS transformers in very close proximity to each other had the problem. I remedied the situation by rearranging the equipment in the rack in such a way that the transformers in the effected equipment were at a greater distance from each other.

And there can be inrush current problems, the most common being very large inrush current as inductors and capacitors within all the equipment connected initially charges simultaneously causing the main breaker for the line to blow.
Nothing much to say to that, is there?
I will accept that things can go wrong, but atm i simply don't have the money to get proper conditioners - i would assume that they have huge caps and other expensive stuff inside, right?

And yes, i can see how inrush current could possibly blow fuses - standard here is 10A fuses at ~230V - maybe the best thing is to have a separate power switch for the mixer.
I live in a tiny apartment, so another circuit is not really an option.

Thx for the insight
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