Amperage Spec for Bridge Rectifier – Denon DRA-300 Receiver Upgrade

[mteetank]

Hi all,
I am doing some restoring on my Denon DRA-300. The Denon uses two capacitors in its power circuit. One is 50V 6800uF and one is 5600uF. I have two 50V 12000 uF 20% left over from a previous project. The rectifier is a Shindengen S4VB 4 amp 200volt.

Now for my question/ concern. I realize that this is quite an increase in Capacitance so my question is if the 4 amp rectifier will be sufficient for the current surge at start up. There is a 4 amp fuse in the rectifier circuit also.

My options are: 1) Replace the rectifier with a higher amp model 6 or 8 amp. 2). Scrape the larger capacitors and reorder ones closer to the original sizes an retain the original bridge rectifier.

Thoughts and recommendations welcome! Thanks much

 

[SIY]

I'd keep the caps to a similar size. Larger caps mean higher charging current pulses. Stresses rectifiers and radiates more noise.

 

[DVDdoug]

The current will be limited by the transformer (or whatever is feeding it) and you'll probably be OK.

Any capacitor has zero capacitive reactance (a short circuit) the instant it first starts charging it so the instantaneous current is whatever the source can supply. But a bigger capacitor will draw more current for a longer period of time because it takes longer to charge and you are charging it with more energy.

It wouldn't hurt to replace the rectifier (and maybe the fuse) or just make sure the rectifier is available. I probably wouldn't put in a bigger fuse if the old one doesn't blow.

 

[mteetank]

Thanks for the info! I now understand the reasoning to not going too large on the power capacitors. As for the Denon power supply, it does not look to be "robust" so I am increasing in reluctant to add any stress to it.

I will need to think about if worth spending the $20-$30 (parts + shipping) to upgrade this receiver. I did order a new multimeter that will measure capacitance but that will still require removal of the caps to read them. Decisions Decisions......... :>)

Again, thanks for taking the time to offer up your thoughts!