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The bridge rectifier bulk capacitors in many heavy Ampegs I've seen are 5600uF (e.g. C51/54 in BA115HPT, C6/14 in BA115HP, C18/19/21/22 in SVT-3 Pro).
5600uF >80V can be somewhat pricy and less common than for example 6800uF or 4700uF. The heavier load the load, the bigger the bulk capacitor needs to be to smoothen the ripple after the bridge rectifier. In my BA115HPT (220W) one is bulging, so I need to replace it. As with everything in physics, there are always compromises -the bigger the capacitor, the slower the response to changes.
The question is, can I replace them with 6800uF in my BA115HPT? I see the B2 (350W) uses 4x 3300uF (2 and 2 in parallel), which would equal 2x 6600uF.
I guess changing both would be good practice when I up the value?
Can I also use 6800uF in my SVT-3 Pro and BA115HP (my father and I have a lot of Ampegs).
On full blast, the BA115HPT draws 320VA. With 240V@50Hz, the ripple is 1.98V with 5600uF and 1.63V with 6800uF.
Or is the 5600uF grossly overrated, so I can replace them with 4700uF (which smooths ripple much faster, but less effective on heavy loads)? With 4700uF the ripple will be 2.36V. Not sure how sensitive the +/-40V rail is?
The BA115a (only 100W) uses 4700uF 50V (although the rail is 40V - seems like a disaster is waiting to happen).
PS. It will always be used on 240V 50Hz (as frequency will slightly affect the value of the bulk capacitor). Maybe this frequency is so low, all mentioned capacitors (4700/5600/6800) will react fast enough...(?)
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