Dumb linear power supply question...

[zamproject]

Hi

As tittle say...
I have difficulty interpreting datasheet about a 1u rack with fitted PSU (Studer modular eurocard ) used to supply dynamic processor prototype

secondary say:
+/-15Vdc, 500mA max

is that 500mA for each rail or for both ?!?

I have issue with rail shutdown, my whole setup take 220/rail 440mA total which is critical if I only get 500mA total
But I'm puzzled as this rack is designed and ready to power eg. 3 dual balancing unit that can eat way over 500mA total (6x170mA @+24dBu)

Setup seem to run fine with a VERO smps @2A per rail



Cheers
Zam

 

[gyraf]

yes, your supply total is 30V@ 0.5A, 15VA if I understand your figures right

 

[Bo Deadly]

is that 500mA for each rail or for both ?!?

I have issue with rail shutdown, my whole setup take 220/rail 440mA total which is critical if I only get 500mA total

It's 500mA for each rail and for both. Same difference. The +15 can source 500mA and the -15 can sink 500mA which is the same as saying 30V can source / sink 500mA.

So if each rail is 220mA, rail to rail is still only 220mA. So the whole setup should be easily satisfied by that supply.

But I'm puzzled as this rack is designed and ready to power eg. 3 dual balancing unit that can eat way over 500mA total (6x170mA @+24dBu)

I assume you mean 3 x 170mA = 510mA which should also work fine if the supply is in good shape.

Setup seem to run fine with a VERO smps @2A per rail

Then it sounds like the linear supply is hurting or it was never that good to begin with. A properly implemented SMPS will be clean as a fresh snowfall compared to some old linear thing with it's mains hum.

 

[zamproject]

Tks to both of you, I'll then check for supply issue asap

I assume you mean 3 x 170mA = 510mA

that was just an example, and nope, for this card it's 170/ch, 2ch/card, 3card total, given for severe peak I suppose (+24dBu) that's not a continuous at this level, idle is at 70

 

[zamproject]

Solved...
Both integrated rectifier have junction failure.
I should have scope around bridge and regulator before reusing this rack/psu

Cheers
Zam

 

[Somkereki]

Hi

As tittle say...
I have difficulty interpreting datasheet about a 1u rack with fitted PSU (Studer modular eurocard ) used to supply dynamic processor prototype

secondary say:
+/-15Vdc, 500mA max

is that 500mA for each rail or for both ?!?

I have issue with rail shutdown, my whole setup take 220/rail 440mA total which is critical if I only get 500mA total
But I'm puzzled as this rack is designed and ready to power eg. 3 dual balancing unit that can eat way over 500mA total (6x170mA @+24dBu)

Setup seem to run fine with a VERO smps @2A per rail



Cheers
Zam

If I may recommend, use a linear power supply in an external shielded box, I don't think it fits in the 1 u height. Worth it !

 

[zamproject]

If I may recommend, use a linear power supply in an external shielded box, I don't think it fits in the 1 u height. Worth it !

Not sure about what you say ? the PSU is linear and fit in the 1U rack as it's designed for it.

 

[Somkereki]

Hi ! Then everything is good! I only thought about the separate box because a lot of interference signals can come from the wall outlet. I've seen on my oscilloscope screen more than 1000 Volts, short (a few microseconds) pulses, which are not directly audible, but can disturb the PLL circuit of the digital clock signal, and can also spoil the completely analog sound, because they disturb the phase of the harmonics. Maybe it's just me too careful, but I've been dealing with sound technology for 40 years (mainly in theaters and recording studios... But I've also worked with famous rock bands on stage. (These small details don't matter there.) Good luck with your work!