Apogee da16x SMPS noise/whining

[lauritz]

I just replaced the electrolytics in the SMPS of my Apogee DA16x converter. All works fine, but after warming up the converter now makes a whining noise (around 4500 Hz) too loud to be ignored, since the converters are in my small control room close by the mixer and workspace. It did'nt do it before, but the biggest cap was starting to bulge and I thought that I would just replace all 3 caps at once. The noise is specifically coming from the inductor (see picture - red laquored thread standing next to the 2 electrolytics ) and i've tried to put some glue on it and some other white elastic goop too, but it does'nt seem to do the job. It was also glued to the neighboring electrolytic before i started messing with it.

Does anybody have a hint as how to get rid of the noise? It's very annoying

all the best
Lauritz

 

[scott2000]

I'm guessing you replaced whatever caps with equivalent specced ones (esr, etc.)? It was quiet before recapping??

 

[dreamix]

Dont have an answer but they do sounds alot even when working fine, some high frequency noise

 

[lauritz]

I'm guessing you replaced whatever caps with equivalent specced ones (esr, etc.)? It was quiet before recapping??

Thanks. I put in some decent quality capacitors, but did not actually check the ESR value...just capacitance, temperature and voltage. So maybe that could be the problem...i'll have another look at the ones i pulled out later today, To see the specifications.

 

[lauritz]

Dont have an answer but they do sounds alot even when working fine, some high frequency noise

They do make some noise, but this is something completely else. I have an AD16x that i also re-capped and that is super quiet compared to the one with this problem