Do I have enough power?

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Common Wiggler
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Do I have enough power?

Post by dip_registered » Fri Feb 14, 2020 5:12 am

Hi! Thanks in advance =)

I’ve started to build this 6U 104 rack:

I have the Intellijel TPS80W on the way. ... -busboard/

The 2 Metasonix tube modules draw about 2.5x their usual usage on cold startup, so that’s I think why they’re listed having high MA on modulargrid.

I check the Metasonix support page and they list:
Intellijel currently has a 30-watt and an 80-watt supply. The 80-watt unit should be able to handle at least three R/RK modules. Please don't try the 30-watt model.

But modulargrid is showing me 3109mA total. Is that overloading / cutting it a bit fine?



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Re: Do I have enough power?

Post by sko87pro » Sat Feb 15, 2020 6:18 am

The metasonix page for the RK3 says:
As with all our modules, it draws about 2.5 times the operating current during "cold" power-up, and you must insure (sic) your power supply can handle the inrush current.
If you’ve spec’d up a 6U case to 3100ma, I’d say you’re way past being able to support valve circuits on startup. The normal current draw isn’t the same as the inrush at power-on. Also, any module pulling 400ma is definitely on the high side so you’ll get fewer total modules attached to the TPS80w. For comparison, a module like MN Maths takes 60ma and a filter like Rossum Evolution takes 80ma.

In any event, modulargrid is only a guide.

The Intellijel page for the TPS80w allows:
+12V output at 3000 mA, -12V output at 3000 mA, +5V output at 1500 mA
If this was my system, I would limit the modules on the TPS80w to 2700ma (leaving 10% headroom). I think you might power up to 3 rows of normal modules within that limit. And then I’d power your valve modules from their own Trogotronic m/15 supply. There’s little point investing in the rich sound of valves but being unable to power them - or damaging your gear. This approach gives you room for expansion in power terms.

The alternative is to down-size what’s attached to the TPS80w: say 2x metasonix (1000ma startup each) and then allow about 700ma of other modules - maybe 10? That’s probably a smaller system than you imagined on modulargrid.

That’s my view, others may comment...

Refs: ... -busboard/

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Re: Do I have enough power?

Post by adaris » Sat Feb 15, 2020 7:31 am

The Modular Grid specs for the two Metasonix modules the OP has in the rack include the inrush current. After startup the current draw should be around 900 mA less than that (between the two of them) according to the manuals. I think if the OP picks up A WMD Soft Start (available at Schneidersladen, and also there is one for sale on Reverb I think) to delay the inrush current from the RK3 then they should be fine. Caveat: I have no experience with that Intellijel case, just going off of the listed specs. I do have experience with running Metasonix modules off of a uZeus power supply with WMD Soft Starts though.

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Re: Do I have enough power?

Post by bbow73 » Sun Feb 16, 2020 1:11 am

What will happen if your system is under powered?
WTB in euro: Oscilloscope -

Common Wiggler
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Re: Do I have enough power?

Post by dip_registered » Wed Feb 19, 2020 4:06 am

Thanks for your replies! I did not know about the WMD soft start. Going to look into that!

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