Hi, I am in the process of restoring an amp from the 90's, Its an old Quasi Complementary design by Audio Innovations.
The power supply has 1 x 10'000uf cap. The marking on the PCB also have markings for 2 x 68'000uf beside the 10'000uf but is not populated.
I wonder if they just decided to use 1 large cap instead of 2x smaller caps due to cost. Is there any benefit to using 2x 6800uf instead of the 1x 10'000uf?
Would 2 x caps provide more current when the volume goes up or is it just better for ripple/smoothing or is there no benefit? the old cap is measuring a bit low and is approx 22 years old.
Thanks.
The power supply has 1 x 10'000uf cap. The marking on the PCB also have markings for 2 x 68'000uf beside the 10'000uf but is not populated.
I wonder if they just decided to use 1 large cap instead of 2x smaller caps due to cost. Is there any benefit to using 2x 6800uf instead of the 1x 10'000uf?
Would 2 x caps provide more current when the volume goes up or is it just better for ripple/smoothing or is there no benefit? the old cap is measuring a bit low and is approx 22 years old.
Thanks.
Hi, it could be a question of maximum height of the casing. 2 x 6800 µF are lower than 1 x 10.000 µF. When a 10.000 µF fitted physically and turned out to be cheaper it was decided to use just 1 cap (assumption). Replace the old one anyway and make sure to choose good quality parts. If possible choose a higher voltage rating and keep physical size the same. Also make sure the height of the new caps does not become an issue. Recently I replaced 6 identical caps for new higher rated ones and the odd shape of the casing prevented 3 of them to be used.
It can not really harm to use 2 x 6800 µF and ripple voltage will be lower. What rectifier diodes are used? Check specifications of those too.
It can not really harm to use 2 x 6800 µF and ripple voltage will be lower. What rectifier diodes are used? Check specifications of those too.
Hi Thanks for replying jean-paul, I can fit 2 6800ufs in there, I would hope the little extra capacitance would give me a little more power and dynamics and clean the powerline even better.
I've owned 3 of these amps in the past but this one seems down on power compared to the other 2. (I haven't measured the capacitance or esr yet on the old cap) When I drive the speakers to higher volumes it seems to be struggling, I do have slightly less efficient speakers now but I am very surprised how much difference the output was lower than from before. This has made me question the output transistors fitted = the 2n3055 that someone said might be romanian ? The other 2 amps had ST brand 2n3055's And I thought someone may have put fakes in the unit. see my post (Hi, Can anybody identify this brand of 2N3055 transistor?)
I was worried about the rectifier diodes being enough to cope, they are 4x separate in5404'd in bridge config. I think they should cope with the extra current from the newer caps. I would like to identify those 4 power transistors to read their spec sheet and compare them with ST 2n3055's
I've owned 3 of these amps in the past but this one seems down on power compared to the other 2. (I haven't measured the capacitance or esr yet on the old cap) When I drive the speakers to higher volumes it seems to be struggling, I do have slightly less efficient speakers now but I am very surprised how much difference the output was lower than from before. This has made me question the output transistors fitted = the 2n3055 that someone said might be romanian ? The other 2 amps had ST brand 2n3055's And I thought someone may have put fakes in the unit. see my post (Hi, Can anybody identify this brand of 2N3055 transistor?)
I was worried about the rectifier diodes being enough to cope, they are 4x separate in5404'd in bridge config. I think they should cope with the extra current from the newer caps. I would like to identify those 4 power transistors to read their spec sheet and compare them with ST 2n3055's