PSU for Transfer Console

[morls]

Hi,

I'm putting together a transfer console, using PCBs from KA-Electronics. Wayne Kirkwood has given me some great advice as my plans have developed, and I'm at the stage now where I need to do some initial testing of the boards. To do this I need to get my power supply up and running, and I'm scratching my head a bit at the moment as to how I can get this together.

The PSU will be in a separate box to the console. Following advice from Wayne, I'm using 2 switching power supplies, one for the audio processing side of things and the other for the relays and switches.

I'm using this supply for the audio: TDK-Lamda CUT355FF
This is the supply for relays/switches: Mean Well LRS-50-24
I'm considering this as the AC Power Entry Module: Astrodyne TDI 084SM.01000.00

What is the recommended/correct way to wire a PSU with 2 switching supplies? Do I need a separate AC power entry module for each, or can they both be wired to the single AC input? If so, what is the recommended/safest way to wire these?

The AC power entry module I've chosen is the medical version, would this be suitable? Here's a grab from the data sheet showing the difference (the version I'm looking at is the 084SM)



Any advice would be very much appreciated.
Cheers
Stephen

 

[warpie]

Why not linear supply?

 

[morls]

I'm following the advice I've been given for the PSU, so don't want to work with other options. Just looking to get these supplies hooked up safely.

 

[JohnRoberts]

I would expect one line cord to be adequate.

JR

 

[morls]

Thanks John,
Would this be the correct wiring?

 

[JohnRoberts]

do the switching supplies not have safety ground connections?

JR

 

[Khron]

do the switching supplies not have safety ground connections?

JR

Not all do. Even ones with earth connection on the mains side, don't necessarily have the output ground hard-wired to earth (only via a Y2 capacitor). I guess, to leave it for the user whether they want the secondary floating or not(?)

 

[morls]

This is the part I'm not sure about. With this setup there are three grounds - AC mains in, CUT35 and LRS-50-24. Is it best to have each grounded separately, or to connect all three to a single ground point? They are all on the AC side.

More info on the CUT35:


And the LRS-50-24 (the data sheet is attached as .pdf):

 

[JohnRoberts]

Not all do. Even ones with earth connection on the mains side, don't necessarily have the output ground hard-wired to earth (only via a Y2 capacitor). I guess, to leave it for the user whether they want the secondary floating or not(?)

That EGC is the safety ground (chassis ground, yadda yadda ground) I was referring to.

The regulated output (low or -) has nothing to do with safety grounding.

JR

 

[JohnRoberts]

This is the part I'm not sure about. With this setup there are three grounds - AC mains in, CUT35 and LRS-50-24. Is it best to have each grounded separately, or to connect all three to a single ground point? They are all on the AC side.

More info on the CUT35:
View attachment 86248

And the LRS-50-24 (the data sheet is attached as .pdf):
View attachment 86250

If the PS are well designed it should not matter much... safety dictates a suitable chassis/EGC ground bond.

JR

 

[Thomas W. Bethel]

I would not use switching type power supplies in any analog gear. I too am building a transfer console and all my supplies are normal "brute force" power supplies. +/- 15VDC for the Main board, +24 VDC for the relays and +12 for the VU meter buffer amps. FWIW.
I would hold up an AM radio, tuned "off station" to the supplies and see how much "hash" they are generating. You might be in for a shock...

 

[pucho812]

any reason why you are using a supply that provides more available current for the +15VDC then the -15VDC?

data sheet shows about half an amp more for there + side instead of the - side.

 

[industrialarts]

I would not use switching type power supplies in any analog gear

IDK - a lot of modern audio gear has switching supplies. Someone correct me if I'm wrong - I stopped working on large format consoles quite a while ago - but I believe SSL uses switching supplies with lots of additional filtering, IIRC

 

[Unit-8]

Hi Morls, here is my solution. I used 3 MeanWell open switching power supplies with 3 different voltages for the relays plus a linear one to power the op amps. If you can, avoid putting them in the same rack case with the other boards.

 

[pucho812]

IDK - a lot of modern audio gear has switching supplies. Someone correct me if I'm wrong - I stopped working on large format consoles quite a while ago - but I believe SSL uses switching supplies with lots of additional filtering, IIRC

The more modern SSL's use SMPSU's as do a lot of other modern console manufactures like trident and tone lux.

 

[waltzingbear]

And Manley

 

[morls]

any reason why you are using a supply that provides more available current for the +15VDC then the -15VDC?

data sheet shows about half an amp more for there + side instead of the - side.

I'm following the suggestions from Wayne Kirkwood's build threads, and both the TDK-Lamda and Meanwell are recommended.

Hi Morls, here is my solution. I used 3 MeanWell open switching power supplies with 3 different voltages for the relays plus a linear one to power the op amps. If you can, avoid putting them in the same rack case with the other boards.

Looks good! I've got mine in a separate case with a 3m cable to connect to the rack case. There's room in this PSU case for extra or larger power supplies if need be, but I'm hoping this basic setup will get the job done.