Hi,
So ive read at different kind of forums etc that you shouldnt go more than 80% of the total PSU power, in my case I have a Doepfer PSU-3 wich have maximum at: (+12 V / 2000 mA, -12 V / 1200 mA, +5 V / 4000 mA, 100 - 230 V), and 3x bus boards
My current set up draws this down below according to MG - My question is, is this safe and will cause not problem?
Power Consumption: 1754 mA +12V | 729 mA -12V | 270 mA 5V
Thanks for answer!
The short answer is: you should be on the safe side with those values.
The Doepfer PSU3s are pretty good and you should be able to run them close to their specified limits. The problem is, that you can't rely 100% on the power consumption specs of your modules here on modulargrid. Most should be close to their actual power consumption. But there's no way to tell how these values were measured, really. Some modules show a significant spike in consumption on power up, most will draw varying amounts of power depending on how they're being used. Has the manufacturer (or user) who added the module here entered the peak value or some average? Or just some random best guess? You can't know for sure without doing your own measurements. So the recommendation of not exceeding a maximum of 80% of the PSU spec also serves as a cushion against too optimistic module consumption specs. Again, it's a recommendation and no hard and fast rule.
Ought to be just fine. You're nowhere close to the limits on the -12 and 5V rails, and only the +12V one is pushing it a bit. But as senor-bling mentioned, Dieter overspecced those power supplies. Even with an inrush, it should handle that like a champ. One thing I would suggest, though, is to try and balance that +12V load as evenly as possible across all three of your busboards. That should give you some leeway on power-up as well.
I have been pretty lucky so far with my 14u MDLR case that has dual 85w power supplies. I have a lot of larger power hungry modules as well like Rossum Mob of Emus. Funny thing is that the Patchwerks tech told me that a customer had issues running that module in his case but it powered up fine in my larger case.
Another couple of cabs I'd thumbs-up based on their power supplies would be ones from Erica and Pittsburgh. In the latter case (no pun intended), those are Monorocket designs, and Monorocket was always known for MASSIVE power overspeccing. The Pitt cabs are no exception. And the Erica stuff also goes overboard on amperage...even their 1 x 84 skiffs sport 1.25A 12V rails!
Thanks for answer here.. So basically how close can i go to 2000MA? Would around 1850 be safe and no problem?
1.85A is pushing it a little. It would be better if you can get that load figure lower, say down around 1.6A. This is easier on the "on the panel" supplies. But if we're talking some sort of heftier internal supply (like the Pitt ones, Doepfer PSU3, etc), this should be OK as those manufacturers tend to build some headroom into their P/Ss. If so, then just take some care to distribute the +12V rails' current load across the distro boards so that one of them isn't bearing the brunt of the current load while the other loafs along.
Yes youre right, i'll rearrange them on the rails. Is there some risk of damaging modules when coming close to the 2000ma?
Yes, i got the doepfer psu-3 case.
The risk is actually more to the power supply...but quite often, when power supplies fail, they puke up a lot of overvoltages and other garbage. But if it's a Doepfer PSU3, those are pretty beefy and they're overspecced. Just rearrange your +12V load so that everything's a bit more load-balanced across the busboards...and actually, the evened-out load might be useful to lower other component stresses, such as the busboard filtering caps, etc.
One other thing I'd recommend would be to get one of Konstant Labs' 1 hp PWRchecker modules. They're conveniently sized, plus they do a bit more than just being an indicator that the busses are functional. Very smart little thing...and for US$28, they're a no-brainer if you don't already have some front panel rail voltage indicators.
Thanks for answer here.. So basically how close can i go to 2000MA? Would around 1850 be safe and no problem?
-- flow3r
It should work fine. I have several doepfer units, one of which is pushed almost to the max on the -12v rail, and full of Frap Tools modules that are fussy about power. No problems at all. Runs great.
I have the same case.
Power Consumption: 1836 mA +12V | 971 mA -12V | 90 mA 5V
All good :)
Hey,
I sent an email to Doepfer regarding this. This is the content of the email I sent:
"Good afternoon,
I am the proud owner of the above case. Very happy with it :) THANK YOU.
The technical details of the power supply give me the following: 2000 mA -12V | 1200 mA -12 V | 4000 mA 5V.
My current draw on the power supply is as follow: 1884 mA +12V | 1099 mA - 12V | 92 mA 5V.
How far can I push the system in terms of power? Is there a threshold that I should take into consideration?
I have tried to balance the +12 V evenly on the 3 rails: https://www.modulargrid.net/e/modules_racks/data_sheet/2347537
Thank you very much in advance for any help and support from you.
Best of all,
Olivier"
This is the answer I got from Doepfer as per today:
"Hello,
the A-100PSU3 outputs 2000mA@+12V, 1200mA@-12V and 2000mA@+12V. Each A-100PSU3 is tested under these conditions before it leaves the factory with so-called dummy loads.
But the A-100PSU3 will not turn on if the currents are beyond the specifications of the A-100PSU3. We discovered that some modules from other manufacturers consume more current than specified by the manufacturer during power on (so-called in-rush current). If the sum of all currents during power on exceeds the A-100PSU3 specifications it will not turn on because it is not able to deliver more than the specified currents.
Best regards
Doepfer Musikelektronik GmbH"
Hope this helps and clarifies :)
