Thought I’d give an update on this, it’s been a while.
After troubleshooting almost every part of my electric installation, I seem to have found the main culprit: shoddy PCB design. It’s a pity, I really enjoy my other Frequency Central stuff, but I cannot with good faith recommend the Routemaster.
Here’s the underside of the board, on which I have traced out the ground trace. Notice the long and winded trace which connects the +12V regulator section (top left) to the ground connector. Same thing for the IDC headers, no bueno.
The supply ripple decreased from 30mV to 6mV. This raises the next question, what is an acceptable ripple level? 6mV is an improvement, but it’s still three times more than the 2mV my FC microbus gave me. At least it isn’t audible on a DC output anymore…
Wow, that’s nuts. Even if for some reason they didn’t want to use a ground plane (is there a reason?) they could easily have done a much more direct connection on the top side.
I have a question about Power Supply as I’m running out of “juice” with my current one. I’m looking into buying 2 or 3 Excalibus: Excalibus DIY Kit
As each one has 1,25A for each rail I would have a need for 3,75A. From what I’ve gathered from other threads I could hook up 2 or even 3 of those Excalibus in parallel (I’ve learned that that’s important )
If I get this power supply: Power Supply 4A Switching Brick
Which has 4A, 60Watt - this should be well enough for 3 Excalibus, right?
Just want to make sure before I order
That’s a good point, but I have a Frequency Central Routemaster at the moment but it only has 500mA per rail.
And my case is 1m wide and has 5 rows now
So I was looking for something with more connectors and more power output. Because I really want to switch on at least the lower part (3 rows) of my case with one plug / button.
If you have any other alternatives I’m very happy to check those out though!
The correct way of connecting multiple PSUs together is to tie together all grounds and the protective earth. However, you should not connect the positive or negative rails of each supply together. They will have small differences in their supply voltages, which will lead to the PSUs back-driving eachother and damage.
Excalibus is rated for up to 1.25 A on each 12 V rail (plus 350 mA on 5 V if you use that). So up to 2.50 A or 2.85 A each. Leaving out the 5 V that’s 30 W each, or 90 W for three Excalibuses.
That’s maximum output power. Of course you would need more than that on the input.
Befaco says (for each) “Input: 9 – 18v (Recommended 45W)”. So 135 W for three.
Of course that doesn’t tell how much power you need — or even how many modules you have (Eurorack? Kosmo?)
@Dud has — what is it now, 5 cases? 6? With 2 rows (Kosmo) each? It’s got to be a roughly similar if not larger number of modules, and he’s apparently doing fine with Frequency Central. Probably one or two per case so maybe as many as 12 of them, but they’re a lot cheaper.
If you really want one-switch turn on, in principle you could use a switched power strip. Turning on one at a time is kinder to the system, though.
right sorry, should have given more context. It’s Kosmo only, so between 10-15 modules per row.
Two cases, one with 3, one with 2 rows. I was hoping to only have one plug per case going out of the row. But it seems like I’d be better off with one wall wart per row and a FC for every row then.
@Dud are you using the small green FC power with a passive board for hooking all those up or are you using the red Routemaster ones?
averaging 41 mA +12 V and, if you leave out the Safety Valve, 20 mA -12 V (32 mA if you include the Safety Valve). 15 modules in a row would work out to about 600 mA on the + 12 V rail which is at the high end of or a bit beyond the FC spec (~500mA at +/-12V), but it depends which modules of course.
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