Need help on power supply caps

There is a circuit board trace from the lug to whatever it connects to, so I don't think adding a few inches of wire would hurt. Besides, you really don't have a choice.

The issue with bigger caps in the power supply is that the in-rush current when you turn it on will be higher, and you risk blowing a fuse or possibly a rectifier. Since your new caps are a little over twice the capacity of the old ones my gut feeling is that it will be OK. The exception would be if the design was poor in the first place and it was operating close to it's limits.

I would go for it.

P.S. You may wish to also check with the manufacturer -- obviously, power supplies are very complex. Here is an interesting read on some of the approaches that can be used:

http://synergy.sager.com/ProductPDFs/PowerTransformer_FilterRatings.pdf#search='rectifier%20ratings%20power%20supply'

If the amp has 35-amp/400V bridge rectifiers, it won't be a problem; if it's less than that (15, 20, 25-A), then see if it's possible to replace them with the 35-A, the largest rating available, if you want to be sure. I agree with Herman, the existing recitfiers should be okay, especially if the amp is rated at 50W or greater.

Believe it or not, most electrolytics work best if run closer to their voltage ratings. I am NOT saying that you should run them up to their voltage limit, but that a lower voltage rating may actually perform better AND fit where the stock caps were. As Ozfly mentioned, 50 or 60 volt caps may actually be a drop in if the caps that you are replacing were of older vintage.

Other than that, i see no problem with running small heavy gauge leads from the caps to the circuit board. In doing so, you may actually be able to improve current flow by routing the leads in a more direct lower resistance path through the use of heavier gauge wiring. Just make sure that the wire itself isn't stressed at the point of connection going into the board or you may end up with a poor connection. This would be due to age and solder fatigue.

Due to the rigidity of the wire pulling on the joint all the time, the board can develop small fissures between the trace and the solder. Conductivity is reduced due to a lack of contact area and sooner or later, such a joint will mature into a break. Sean
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Sean- I would agree especially with BGs you don't have to use the standard 2-3X the working voltage for the rated voltage on the cap. What's your feeling about bypassing the main power supply caps with a small film cap, and any recos on what brands you prefer?

Oldcar63- Did you measure the working voltage on the 4200uf/47volts caps you're replacing? The BG STD4700/50 is a lot less money and would still be a big improvement.