newbie question

What do you do when you run out of connections for a skiff (you have power to spare but more modules than connectors)? Is it simple to add or daisy chain on extras? Those 2hps save a lot of space but seem to add up quick where # modules-to-connectors go.

if you are still under 70-80% with the extra modules it is possible to add an additional busboard

it is also possible to make double (or triple) headed power cables* - I think intellijel make these or small flying busboards that might be suitable

it really depends on the space in the rack the 2hp modules can also be quite deep so this may have an impact on which solluttion will work best for you

*this is really quite easy and inexpensive to do and can be done with no specialist tools

Just use any decent flying bus cable with the right amount of headers. However, DO keep an eye on your current draw figures...you don't want to exceed 3/4ths of the power supply's current capacity due to potential problems with power inrush, which can send your amperage draw OVER the design limit for the p/s for a small fraction of a second...which is enough to cause problems. Also, if there's a wide gap between potential supply and draw load, this means your p/s can run cooler...and given that heat is Public Enemy #1 for electronic components, that's something you want.

Thanks for the tips, I hadn't yet heard about keeping to < 75% draw, I'd been planning to ramp it closer to full. I'll avoid that.

you don't want to exceed 3/4ths of the power supply's current capacity due to potential problems with power inrush,
-- Lugia

Clarification sought : 3/4 of the power supply's total capacity, or on each rail separately? In my box the +12V is getting pretty close to the wind, but there is very little on -12V.

The +12V rail is the main one that modules use. Not everything requires the -12V rail, and these days the trend with the +5V rail is for some manufacturers to put the downconversion onboard the module that needs it. But the current headroom issue is per rail, since the two 12V and 5V rails are all powered by different circuits. And you can pop the +12V by overdrawing, but leave the -12 and +5 (unless the +5 requires the +12) more or less intact. So if you've got 1500 mA on the +12V rail, and the P/S feeding the rail is rated for 2A, you're fine. But getting too much further above that 1500 mA gets a bit dicey, particularly if the build is very module-dense as each module will have SOME inrush...and adding each of those up can get you into the trouble zone pretty quickly.

EDITED Apr 12th 2021, 01:29

Thanks... not the answer I wanted, but better than fire and smoke!

Power Consumption: 963 mA +12V | 425 mA -12V
Doepfer PSU2 : Output voltages/currents: +12V DC/1200mA, -12V DC/1200mA

I still have so many hp left! Never thought uncle Dieter would let me down :(

Pittsburgh Modular has some real beefy cases if you can make it work @the-erc, power for days. If not maybe we can get @Lugia to sign off on my Micro Zeus idea from the other day.

Hi The-Erc,

If you buy nowadays a new Doepfer case, it comes with the PSU-3 and that one goes up till 2000 mA for the +12 V, that's in most cases sufficient. I agree with you that the PSU-2 with only 1200 mA for the +12 V can be challenging.

Or you could buy the PSU3 unit and replace that with your current PSU2, I do think that's possible but please check before doing so (in case you are interested).

Kind regards, Garfield.

@troux @garfield -- I think I will buy a PSU3 from Doepfer and swap out the PSU2. It seems to be pretty easy. But as it happens I have a spare "rack-wart" power module lying around that I can use to tide me over until then.

Sounds like a rock-solid plan

Excited to hear the results!

that's great!

EDITED Aug 23rd 2021, 15:04

Sorry if I am doing a hyjack here, but I am a newbie and would like to know where to go to post a hello and ask a few questions
Thanks
Mitch

EDITED Aug 23rd 2021, 15:03

If you have power left and run out of hp just call yourself lucky. Appreciate that your setup does not stress the PSU, it´s a much better place to be in compared to the opposite.

Also: If you go for new thingies, not all PSUs are created equal. For example, between my rackbrute and mantis, there is a HUGE difference regarding the power-on noise: the same module that POPS loudly in the rackbrute still pops in the mantis, but at a much more civilized level. And yes, this is a dediated output module and the level is set to zero. Still popping.

Mantis power is very good - it's effectively the tiptop studio bus - it's really quiet right up to video rates (MHz) where ripple/noise is actually visible on screen