SMPS500R Auxiliary Voltage

[von Ah]

For those of you familiar with the Connexelectronics SMPS500R, how can the auxiliary output be changed from +/- DC to single DC voltage?

My unit is slightly different than the documentation in that the main outputs are next to the two larger caps and are spade connectors.

Also, should I be concerned about the two Samyoung SMK 63v 4700uF caps and one Lelon 200v 1000uF cap? This is the +/-60vdc model, so should those two caps be at least 80v?

 

[von Ah]

I finally found a nugget of insight from the big Connexelectronics SMPS thread.

Switched Mode Power Supplies (SMPS)

...the aux. output can provide up to 500mA each rail, do not exceed this current otherwise the fuses which protect the aux section will burn. 500mA is more than enough for any preamplifier stage or aux. circuitry. the negative aux. output can be left floating if is not used. does not require any load and is useless to waste power by adding any resistor.

Though this was for the SMPS300R, I will test this out.

I also found that 63v caps might be too low and I might need to replace those.

Switched Mode Power Supplies (SMPS)

... the output voltage of the power supply can be adjusted to values above +-60V which is too close to the working voltage of the 63V caps. then, i should chose the 80V caps instead, for which i had available the 2200uF value. the caps can be increased to 6800uF, but make sure their working voltage to not be exceeded. no other part should be changed unless on the circuit which is supplied by the smps there are other large caps which will count for more than 10mF total capacitance for each rail.

 

[von Ah]

I successfully replaced the 4700uF 63V caps with Rubycon 6800 80V caps.

Main output and auxiliary voltage measured the same as before replacement. Hopefully it performs well under load. The foil layer on the underside is thin and delicate. No reasonable person should be replacing parts on these SMPS, but I thought I needed safety headroom since it will be used at 60vdc. It would be ironic if my desoldering and replacing caps made it less safe than keeping the 63v caps.

I left my meter on the outputs to watch the voltage slowly drop after it was switched off and unplugged from mains AC. After it went down below 10vdc I put the unit back in its box.

 

[0hm5law]

I'm guessing you purchased the 120VAC input version which has two smaller capacitors that are in series which is enough.

I don't think you needed to change the capacitors. The voltage output +-DC is normal for polarity connection I believe.

What amplifier are you matching this with?

 

[von Ah]

Thanks. Yes, I have the 120vac version. It seemed counterintuitive to have 63v caps on a +-60vdc output smps.

I’m using one smps500r per channel for this hybrid amp:
Ultra-high performance, yet rather simple - hybrid and more!

 

[0hm5law]

Cool. Coming along. Hope it all works out. Have fun.

 

[von Ah]

Thanks! It’s operational, but I’m going to spend a lot of time chasing down a hum in the output. 😀