(How) Can I upgrade/mod a Soundcraft CPS-150 with a JLM power supply?

I was going to refurb a CPS 150 power supply when I got the great idea that I can probably  upgrade the thing significantly by basically keeping the chassis, and transformer, and replacing all the other guts.  The transformer has 6 "output" wires that connect to the pcb that regulates the current.  2 : +64v for the 48v, 2: +24v, and 2: -24v.  Here is a link that shows it:

http://juggernautmusic.com/wp-content/uploads/2013/10/cps-150-mod.pdf

I did some searches and can't find a single thing about doing something like this, despite there being tons of threads and pages about modding a CPS 150.  There is room in there, heat sinks on the back, standoffs already in place, it seems too good to be true... so it probably is!  I'll email JLM on Monday (US time), but its currently bright and early on Sat morning in JLM land, and I don't want to interupt their saturday morning cartoons. 

If anyone knows how to make this work,  I feel like it could become a very popular mod for this power supply.    Here's a link to JLMs  power supplies.

https://www.jlmaudio.com/shop/power-supply-kits.html?display_tax_prices=1

I think jlm use lm317/337 regulators in their produkts. Thoose chips are rated for 1.5A max.

Cps150 uses lm338/339 with 5A capability.

Everything else is just diodes caps and resistors.

I put some larger main filter caps in my cps150 and way bigger diode bridges.
Tha bass was cleaned up a bit.

Yes, the JLM power supplies max at 1.5A per rail with the 10A bridge rectifier, but the CPS 150 is only rated at 1.25A.  I think they should work fine together.

Update:  Ok, I've learned that the secondaries of the +24v  windings can be connected to make 48-0-48 that can be attached to the JLM supplies.  I guess it seems obvious now, but the fact that the schematic didn't specifically say 0v  caused me to be overly cautious.

Now I guess my final question:  The JLM supply has a pump charge for 48v out, but I still have an unused winding on the transformer that was originally used for 48v.  Would I be able to eek out any (useful) extra juice from the transformer by using that winding, and NOT using the 48v from the JLM supply?

IMO, you should do a better research  how to really upgrading CPS150. If you change the regulators board with JLM version you will downgrade it. I don't say the JLM power is bad at all. For example, just go to Mouser and see difference in price between LM338k you have in CPS150 and LM317 you like to use instead.

moamps said:

IMO, you should do a better research  how to really upgrading CPS150. If you change the regulators board with JLM version you will downgrade it. I don't say the JLM power is bad at all. For example, just go to Mouser and see difference in price between LM338k you have in CPS150 and LM317 you like to use instead.

Click to expand...

I'm obviously no expert here, but I was under the impression that the  difference between those two regulators is that the LM317 puts out a max of 1.5A and the LM338 has a max of 5A.  So the 338 is more robust, and thusly slightly more expensive.

That said, I've done a ton more reading about power supplies in general and about my CPS150, and it seems that the weak spot of the CPS150 is in fact the transformer, and not the other circuitry... so the one part I hoped to keep is actually the one part that probably should be upgraded.  Back to the drawing board!

I've replaced the CPS-150 with this PSU:

https://www.amb.org/audio/sigma22/

Discrete, low noise, low impedance. Big difference.

sexxie

Whats the problem with the original CPS-150 PSU?

dysenterygary said:

it seems that the weak spot of the CPS150 is in fact the transformer

Click to expand...

I'm not familiar with this PSU, but could you elaborate on why is the transformer the weak spot?

Thanks

Whoops said:

I'm not familiar with this PSU, but could you elaborate on why is the transformer the weak spot?

Click to expand...

Mine hums loudly.

living sounds said:

Mine hums loudly.

Click to expand...

Acoustic noise?

That could be probably solved by dipping it in Varnish and baking it.

Worst case scenario replacing the transformer for a another onw, maybe even a Toroidal transformer.

But I'm still not seeing the need to replace the PSU, maybe I'm missing something that's why I asked

I recently zipped together a bunch of LT1086’s heat sinked to large aluminum bars to replace a CPS 450. They worked great under load up to about 4 or 5 amps but I ended up using international supplies just for the ease and convenience.. API uses international style supplies in their large format consoles

Out of interest, what are "international supplies" or "international style supplies"??

http://internationalpower.com/

Walrus said:

Out of interest, what are "international supplies" or "international style supplies"??

Click to expand...

What moamps said.

There are a few knock off brands too