I am planning to replace the 8 x 6800uF 63V caps on the amp.
I am wondering if I use 8200uF or even 10000uF ones 63V, will there be any difference?
I am wondering if I use 8200uF or even 10000uF ones 63V, will there be any difference?
You may stress the diodes or transformer from the energy required to charge the new over value capacitors.
And the high current spikes that charge the capacitors can generate EMC problems, so noise on the sound.
This is really important, I've also seen protection relay contacts fused together because the owner decided to upgrade to a much higher cap value.
Download Duncan's PSU Designer II (Here: PSUD2) and see for yourself. Try a heavy load on a small filter cap vs. a large cap, it will be obvious then, the larger the cap is, the larger the charging current spikes will be.
Mike
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ZERO problems since you are well within original capacitor value tolerance or very close.
The above Doom or End of the World comments might apply if you were multiply current capacitance by 10 or 20; since you are not, attribute them to old wive´s fears.
FWIW the feared charging pulse will not be larger but longer, no big deal.
Suggest reading about RC circuits, it will clear your doubts.
It can affect the noise level of the amp, it mostly depends on how the power and signal conductors are physically laid out, and the PSRR of the circuit too. And as JMFahey said above, that small of a change isn't likely to be audible in any way.
Mike
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I don't agree. It is longer only at start. But at steady state the amplitude of charging current has to increase because of a lower cap impedance.
With larger caps they droop less voltage between charging pulses (less ripple), so the rectifier will conduct for less time, at higher currents.
You are assuming it does not discharge with load. To recharge, The impedance will be lower... not a deal breaker though.